💊 Drug Table — every Pharm 4 drug

193 drugs across all systems — class, indication, mechanism, adverse effects, and pearls. A red ⚠ BBW line appears only for drugs with a black-box warning. Type in the box to filter by drug, class, or keyword.

Drug	Class	Indication	MOA	Key ADRs	Pearls & Black Box
Ketorolac Stones	NSAID	Renal colic (1st-line)	NSAID — inhibits COX/prostaglandins	GI bleed, renal injury	Max 120 mg/day; avoid if intervention likely/renal impairment ⚠ BBW: GI bleeding, renal, bleeding risk; ≤5 days
Morphine Stones	Opioid	Renal colic pain	Mu-opioid agonist	Sedation, constipation, resp depression	Less favorable in renal impairment
Hydromorphone Stones	Opioid	Renal colic in renal impairment	Mu-opioid agonist (more potent)	Sedation, resp depression	Preferred over morphine when renal function is poor
Tamsulosin Stones	α1-blocker	Medical expulsive therapy; BPH	Selective α1-blocker — relaxes ureter/bladder neck	Orthostatic hypotension, retrograde ejaculation, floppy iris	MET for ureteral stones 5–10 mm; uroselective
Potassium citrate Stones	Urinary alkalinizer	Uric acid / calcium stones	Alkalinizes urine, ↑citrate	GI upset, hyperkalemia	Dissolves uric acid stones; CI in renal insufficiency
Nitrofurantoin UTI/OAB	Urinary antibiotic	Uncomplicated cystitis	Damages bacterial DNA	GI upset, pulmonary/hepatic toxicity (chronic)	100 mg BID ×5 d; avoid CrCl<30 and at term in pregnancy
TMP-SMX UTI/OAB	Sulfonamide/folate antibiotic	Cystitis, pyelo, PJP prophylaxis, MRSA	Sequential folate-synthesis blockade	Rash, hyperkalemia, SJS/TEN, blood dyscrasias	CI: pregnancy, sulfa allergy, G6PD; ↑warfarin/INR ⚠ BBW: SJS/TEN, blood dyscrasias
Ciprofloxacin / Levofloxacin UTI/OAB	Fluoroquinolone	Pyelonephritis, complicated UTI, GU infection	Inhibit DNA gyrase/topoisomerase IV	Tendon, QT, CNS, dysglycemia	CI pregnancy/peds/MG; separate from antacids/iron ⚠ BBW: Tendon rupture, neuropathy, MG exacerbation, CNS
Ceftriaxone UTI/OAB	3rd-gen cephalosporin	Inpatient pyelo, gonorrhea, epididymitis, PID (500 mg IM x1; 1 g if ≥150 kg)	3rd-gen cephalosporin — cell-wall synthesis	Biliary sludge, diarrhea; neonatal Ca precipitation	Does NOT cover chlamydia — pair with doxycycline ± metronidazole for PID; incompatible with Ca-containing IV fluids including lactated Ringer's
Oxybutynin / Solifenacin / Tolterodine UTI/OAB	Antimuscarinic	Overactive bladder (urge)	Antimuscarinic — ↓detrusor contraction	Dry mouth, constipation, blurred vision, urinary retention, cognitive impairment	CI narrow-angle glaucoma, retention; reverse toxicity with physostigmine
Trospium UTI/OAB	Antimuscarinic	OAB in polypharmacy	Antimuscarinic (poor CNS penetration)	Dry mouth, constipation	Preferred antimuscarinic with polypharmacy/cognitive concern
Mirabegron / Vibegron UTI/OAB	β3 agonist	Overactive bladder	β3-adrenergic agonist — relaxes detrusor	Hypertension, headache, nasopharyngitis	Vibegron: no CYP2D6 interactions, OK with BPH tx
Phenazopyridine UTI/OAB	Urinary analgesic	Dysuria symptom relief	Urinary tract analgesic (azo dye)	Orange urine/secretions, methemoglobinemia	Symptomatic only, not a cure; ≤2 days; warn about staining
Lactated Ringer's Fluids	Balanced crystalloid	Large-volume resuscitation	Balanced isotonic crystalloid	Rare	Preferred over saline (less hyperchloremic acidosis)
Normal saline (0.9%) Fluids	Isotonic crystalloid	Resuscitation, dehydration	Isotonic crystalloid	Hyperchloremic metabolic acidosis (large volume)	CI CHF/renal insufficiency with volume overload
3% hypertonic saline Fluids	Hypertonic crystalloid	Symptomatic severe hyponatremia	Raises serum Na, shifts water out of cells	Osmotic demyelination if too fast	Correct slowly; central line preferred
Furosemide (loop) Fluids	Loop diuretic	CHF, edema, HTN	Inhibits Na/K/2Cl in loop of Henle	Hypokalemia/-natremia/-calcemia, ototoxicity, hyperuricemia	Works at CrCl<30; ethacrynic acid safest with sulfa allergy
Metolazone Fluids	Thiazide-like diuretic	Diuretic-resistant edema	Thiazide-like — distal tubule Na reabsorption	Hypokalemia, hyperuricemia, hyperglycemia	Retains efficacy at GFR<20; synergistic with loops
Tolvaptan Fluids	Vasopressin V2 antagonist (vaptan)	Euvolemic/hypervolemic hyponatremia	V2 (vasopressin) receptor antagonist → aquaresis	Thirst, overcorrection	CI liver disease/cirrhosis; avoid strong CYP3A inhibitors ⚠ BBW: Hepatotoxicity; initiate in hospital
Potassium chloride Fluids	Electrolyte	Hypokalemia	K+ replacement	GI irritation, hyperkalemia	Hyperkalemia = stabilize → shift → eliminate: IV calcium if K >7 or ECG changes, then insulin/glucose and β-agonist, then binders or dialysis
BCG (intravesical) Oncology	Immunotherapy (live)	Non-muscle-invasive bladder ca / CIS	Live attenuated M. bovis → immune response	Dysuria, cystitis, flu-like → sepsis	CI: immunosuppression, active TB, UTI, gross hematuria, traumatic cath
Mitomycin C Oncology	Alkylating chemo	Intravesical bladder ca after TURBT	Alkylating — DNA cross-linking	Dysuria, hematuria, ↑Cr, myelosuppression	CI perforated bladder
Cisplatin Oncology	Platinum alkylating	Urothelial, TNBC, many solids	Platinum — DNA cross-linking	Nephrotoxicity, ototoxicity, neuropathy, N/V	Aggressive hydration; combine with gemcitabine for bladder ⚠ BBW: Nephrotoxicity, ototoxicity, myelosuppression
Doxorubicin Oncology	Anthracycline	Breast, leukemia, lymphoma	Anthracycline — topoisomerase II, DNA damage	Cardiotoxicity, red urine, alopecia	CI EF<50%; reverse cardiotoxicity with dexrazoxane ⚠ BBW: Cardiotoxicity, myelosuppression, secondary AML
Bleomycin Oncology	Antitumor antibiotic	Hodgkin, testicular, cervical	DNA strand breaks (free radicals)	Pulmonary fibrosis, skin changes, fever	Cumulative lung toxicity ⚠ BBW: Pulmonary fibrosis
Cyclophosphamide Oncology	Alkylating agent	Breast ca; ANCA vasculitis/GN	Alkylating — DNA cross-link (acrolein metabolite)	Hemorrhagic cystitis, myelosuppression, SIADH, infertility	Prevent cystitis with mesna + hydration; PJP prophylaxis ⚠ BBW: Myelosuppression, bladder toxicity, secondary malignancy
5-FU / Capecitabine Oncology	Antimetabolite (pyrimidine)	Colorectal, breast, GI; topical skin ca	Antimetabolite — thymidylate synthase inhibitor	Mucositis, diarrhea, hand-foot syndrome, myelosuppression	CI DPD deficiency (fatal); reverse OD with uridine triacetate
Paclitaxel / Docetaxel (taxanes) Oncology	Taxane (antimicrotubule)	Breast, others	Stabilize microtubules → arrest mitosis	Neuropathy, neutropenia, hypersensitivity	Premedicate with steroids/antihistamines ⚠ BBW: Neutropenia, anaphylaxis (paclitaxel)
Irinotecan Oncology	Topoisomerase I inhibitor	Metastatic colorectal	Topoisomerase I inhibitor	Early (cholinergic) & delayed severe diarrhea, neutropenia	Delayed diarrhea is dose-limiting ⚠ BBW: Severe diarrhea, myelosuppression
Tamoxifen (SERM) Oncology	SERM	ER+ breast cancer; risk reduction	Estrogen antagonist (breast) / agonist (endometrium, bone)	Hot flashes, VTE, endometrial cancer, cataracts	Avoid strong CYP2D6 inhibitors (fluoxetine/paroxetine) ⚠ BBW: VTE (DVT/PE), stroke, endometrial cancer
Aromatase inhibitors (letrozole/anastrozole) Oncology	Aromatase inhibitor	Postmenopausal ER+ breast ca	Block estrogen synthesis	Arthralgia, bone loss, hot flashes	Give Ca/vit D; CI premenopausal
Trastuzumab Oncology	HER2 monoclonal antibody	HER2+ breast cancer	Anti-HER2 monoclonal antibody	Cardiotoxicity, infusion reaction	Monitor LVEF; avoid concurrent anthracyclines ⚠ BBW: Cardiotoxicity, embryo-fetal toxicity
CDK4/6 inhibitors (palbociclib) Oncology	CDK4/6 inhibitor	HR+/HER2− metastatic breast ca	Inhibit CDK4/6 → arrest cell cycle	Neutropenia, diarrhea, fatigue	Monitor CBC; CYP3A4 interactions
Checkpoint inhibitors (pembrolizumab/atezolizumab) Oncology	Immune checkpoint inhibitor	Urothelial ca, TNBC, others	PD-1/PD-L1 blockade → immune activation	Immune-mediated pneumonitis/colitis/hepatitis/endocrinopathy	Manage toxicity with corticosteroids; monitor LFTs/TSH/cortisol ⚠ BBW: Immune-mediated adverse reactions
Silodosin / Alfuzosin Prostate	α1-blocker	BPH LUTS	α1-blocker — relaxes prostate/bladder neck	Orthostasis, retrograde ejaculation, floppy iris	Uroselective; additive hypotension with PDE5i
Finasteride / Dutasteride Prostate	5-α-reductase inhibitor	BPH, androgenetic alopecia	5-α-reductase inhibitor — ↓DHT	↓libido, ED, gynecomastia, depression	Lowers PSA ~50%; teratogenic — women shouldn't handle; 3–6 mo onset
Leuprolide / Goserelin Prostate	GnRH agonist	Advanced prostate cancer (ADT)	GnRH agonist — pituitary downregulation	Hot flashes, ED, osteoporosis, tumor flare	Initial testosterone flare — cover with anti-androgen
Relugolix Prostate	GnRH antagonist	Advanced prostate cancer	Oral GnRH antagonist	Hot flashes, fatigue, MSK pain	No flare, rapid castration/recovery; fewer CV events
Bicalutamide Prostate	Nonsteroidal antiandrogen	Prostate cancer (with ADT)	Nonsteroidal androgen-receptor blocker	Gynecomastia, hot flashes, hepatotoxicity	Monitor LFTs; may ↑warfarin/INR
Enzalutamide Prostate	Androgen-receptor inhibitor	mCRPC / mHSPC	2nd-gen androgen-receptor signaling inhibitor	Fatigue, hot flashes, HTN, rare seizures	Avoid with seizure history; strong CYP3A4 inducer
Sildenafil / Tadalafil / Vardenafil / Avanafil ED	PDE-5 inhibitor	Erectile dysfunction (tadalafil also BPH/PAH)	PDE-5 inhibitor → ↑cGMP → smooth-muscle relaxation	Headache, flushing, nasal congestion, NAION, priapism	CI with nitrates (severe hypotension); require sexual stimulation
Alprostadil ED	Prostaglandin E1	ED (2nd-line), intracavernosal/MUSE	Prostaglandin E1 → ↑cAMP vasodilation	Penile pain, priapism, fibrosis	Only FDA-approved intracavernosal monotherapy; CI sickle cell/Peyronie
Phenylephrine (intracavernosal) ED	α1 agonist	Ischemic priapism	α1 agonist → detumescence	Hypertension, bradycardia	First-line for priapism >4 h; monitor CV status
Fluconazole ED	Azole antifungal	Uncomplicated vulvovaginal candidiasis 150 mg PO x1; candidal balanitis	Azole — inhibits fungal CYP450 (ergosterol)	Headache, hepatotoxicity, QT	Avoid oral route in pregnancy — use a 7-day topical azole; strong CYP inhibitor (statins, warfarin, sulfonylureas)
Doxycycline GU/STI	Tetracycline	Chlamydia, epididymitis, syphilis adjunct	Tetracycline — inhibits 30S ribosome	Photosensitivity, esophagitis, tooth/bone effects	Avoid in pregnancy and children <8 yr; take with food and a full glass of water, stay upright 30 min (pill esophagitis)
Vancomycin GU/STI	Glycopeptide	MRSA (necrotizing infection, systemic)	Inhibits cell-wall (D-Ala-D-Ala)	Nephro/ototoxicity, red-man syndrome	IV for systemic only; not active vs gram-neg/anaerobes
Piperacillin-tazobactam GU/STI	Penicillin + β-lactamase inhibitor	Necrotizing/mixed infection (Fournier)	Penicillin + β-lactamase inhibitor	Rash, diarrhea, seizures (high dose)	Combine with vancomycin for MRSA + debridement
Metronidazole GU/STI	Nitroimidazole	Anaerobes, trichomonas, BV, pancreatitis	Forms toxic radicals damaging DNA	Metallic taste, neuropathy, disulfiram reaction	Avoid alcohol (disulfiram-like reaction) ⚠ BBW: Carcinogenic in rodents — reserve for indications with clear benefit
Leucovorin GU/STI	Folinic acid (rescue)	Methotrexate rescue	Folinic acid — bypasses DHFR block	Rare	Antidote for MTX toxicity/bone-marrow suppression
Combined OCP (ethinyl estradiol + progestin) Contraception	Estrogen-progestin contraceptive	Contraception	Suppress ovulation (↓FSH/LH); thicken mucus	VTE, MI, stroke, melasma, breakthrough bleeding	CI migraine w/ aura, smoker ≥35, VTE hx; ↓ovarian/endometrial cancer
Progestin-only pill (norethindrone) Contraception	Progestin	Contraception (estrogen-contraindicated)	Thickens cervical mucus	Irregular bleeding, cysts	Must take same time daily
Levonorgestrel (IUD / Plan B) Contraception	Progestin	LARC; emergency contraception	Progestin — thins endometrium, thickens mucus; EC suppresses ovulation	Irregular bleeding	Plan B best <24 h, up to 5 days
Etonogestrel implant (Nexplanon) Contraception	Progestin implant	LARC (most effective)	Inhibits ovulation, thickens mucus	Irregular bleeding	Only absolute CI = current/past breast cancer
Medroxyprogesterone (Depo) Contraception	Injectable progestin	Contraception IM/SQ q13 wk	Suppresses LH surge, thins endometrium	Weight gain, ↓bone density, delayed fertility	Bone loss is reversible; the decrement is described with long-term use beyond ~5 yr — no hard 2-yr stop if it remains the best method ⚠ BBW: Bone mineral density loss
Copper IUD (Paragard) Contraception	Non-hormonal (spermicidal)	LARC; emergency contraception	Spermicidal (copper); 10 yr for the 380 mm² device, 3 yr for the 175 mm² device	Heavier menses, dysmenorrhea	Only method OK in current breast cancer; EC within 5 days
Clomiphene WH/Fertility	SERM	Ovulation induction (2nd-line)	Blocks hypothalamic ER → ↑FSH/LH	Hot flashes, multiple gestation, visual changes	Letrozole is 1st-line in PCOS; max ~6 cycles; CI ovarian cysts/liver disease
Letrozole WH/Fertility	Aromatase inhibitor	Ovulation induction (PCOS, off-label)	Aromatase inhibitor → ↑FSH/LH	Fatigue, arthralgia	Preferred in PCOS; CI pregnancy
Gonadotropins (FSH/LH/hCG) WH/Fertility	Gonadotropins	Ovulation induction / IVF	Direct ovarian stimulation; hCG triggers ovulation	OHSS, multiple gestation	Monitor estradiol + follicular ultrasound ⚠ BBW: OHSS, multiple births
Estrogen (HRT) WH/Menopause	Estrogen	Vasomotor symptoms, GU atrophy	Estrogen-receptor agonist	VTE, stroke, endometrial cancer (unopposed)	Add progestin if uterus intact; transdermal = lower VTE ⚠ BBW: CV events & breast cancer
Raloxifene (SERM) WH/Menopause	SERM	Osteoporosis; breast-ca risk reduction	ER agonist (bone) / antagonist (breast, uterus)	VTE, hot flashes	Alternative to progestin in some women ⚠ BBW: VTE, stroke risk
Danazol WH	Weak androgen	Endometriosis	Weak androgen; suppresses FSH/LH	Weight gain, acne, hirsutism	Androgenic side effects limit use
Oxytocin OB	Uterotonic (pituitary hormone)	Labor induction; postpartum hemorrhage	Stimulates uterine contraction	Uterine tachysystole → fetal distress, hyponatremia	IM first-line for PPH prevention; target 2–3 contractions/10 min
Misoprostol / Dinoprostone OB	Prostaglandin	Cervical ripening / induction	Prostaglandin → cervical softening + contractions	Diarrhea, uterine tachysystole	Misoprostol also for medical abortion/PPH
Labetalol / Nifedipine / Methyldopa OB	Antihypertensives	Pregnancy hypertension	β/α-blocker; CCB; central α2-agonist	Bradycardia (labetalol), edema (nifedipine)	Pregnancy-safe alternatives to ACE/ARB
Magnesium sulfate OB	Electrolyte/anticonvulsant	Preeclampsia/eclampsia seizure prophylaxis; tocolysis	CNS depressant; smooth-muscle relaxation	Flushing, ↓reflexes, resp depression	Monitor reflexes/RR; antidote = calcium gluconate
Betamethasone OB	Glucocorticoid	Fetal lung maturity (preterm)	Glucocorticoid → surfactant production	Maternal hyperglycemia	Give 24–34 wk when preterm birth anticipated
Rho(D) immune globulin OB	Immune globulin	Prevent Rh alloimmunization	Passive anti-D antibodies destroy fetal Rh+ cells	Injection reaction	300 mcg at 28 wk + within 72 h of delivery/bleeding
Heparin / LMWH OB	Anticoagulant	Anticoagulation in pregnancy	Potentiates antithrombin	Bleeding, HIT (heparin), osteoporosis	Warfarin is teratogenic — use heparin instead
Insulin — rapid (lispro/aspart/glulisine) Diabetes	Insulin (rapid)	Prandial coverage	Activates insulin receptor → glucose uptake	Hypoglycemia, weight gain	Cover meals; onset ~15 min
Insulin — basal (glargine/detemir/degludec) Diabetes	Insulin (long-acting)	Fasting/basal coverage	Insulin receptor agonist	Hypoglycemia	Once daily; covers fasting glucose
Metformin Diabetes	Biguanide	Type 2 DM (1st-line)	↓Hepatic gluconeogenesis; ↑insulin sensitivity	GI upset, B12 deficiency, lactic acidosis	Hold with contrast/renal dysfunction; no hypoglycemia/weight gain ⚠ BBW: Lactic acidosis (rare)
Sulfonylureas (glipizide/glyburide) Diabetes	Sulfonylurea	Type 2 DM	Close K-ATP channel → ↑insulin secretion	Hypoglycemia, weight gain	Glyburide avoided in elderly/renal
GLP-1 agonists (semaglutide) Diabetes	GLP-1 receptor agonist	Type 2 DM, obesity	↑Glucose-dependent insulin, ↓glucagon/appetite	Nausea, pancreatitis	Weight loss + CV/renal benefit; hold before surgery (aspiration) ⚠ BBW: Thyroid C-cell tumors (rodent)
SGLT2 inhibitors (empagliflozin) Diabetes	SGLT2 inhibitor	Type 2 DM, HF, CKD	Block proximal-tubule glucose reabsorption	Genital infection, euglycemic DKA, volume depletion	CV/renal/HF benefit independent of glucose
DPP-4 inhibitors (sitagliptin) Diabetes	DPP-4 inhibitor	Type 2 DM	Inhibit DPP-4 → ↑incretins	Well tolerated; pancreatitis (rare)	Weight-neutral, modest efficacy
Pioglitazone (TZD) Diabetes	Thiazolidinedione	Type 2 DM	PPAR-γ agonist → ↑insulin sensitivity	Edema, weight gain, fractures	CI in HF; monitor edema ⚠ BBW: Heart failure
Acarbose Diabetes	α-glucosidase inhibitor	Type 2 DM (postprandial)	α-glucosidase inhibitor — delays carb absorption	Flatulence, diarrhea	Treat hypoglycemia with glucose, NOT sucrose
Pramlintide Diabetes	Amylin analog	Adjunct to insulin	Amylin analog — slows gastric emptying	Nausea, hypoglycemia	Do not mix with insulin in same syringe ⚠ BBW: Severe insulin-induced hypoglycemia
Glucagon Diabetes	Counter-regulatory hormone	Severe hypoglycemia	↑Hepatic glycogenolysis/gluconeogenesis	Nausea, vomiting	CI pheochromocytoma, insulinoma
Meperidine Pancreatitis	Opioid	(AVOID in pancreatitis)	Mu-opioid agonist	Neurotoxic metabolite (normeperidine), seizures	Use morphine/hydromorphone instead
Ondansetron Pancreatitis	5-HT3 antagonist	Nausea/vomiting	5-HT3 receptor antagonist	Headache, constipation, QT prolongation	Watch QT with other QT drugs
Imipenem-cilastatin / Meropenem Pancreatitis	Carbapenem	Infected pancreatic necrosis	Carbapenem — cell-wall synthesis inhibition	Seizures (imipenem), diarrhea	PCN allergy → cipro + metronidazole
Pancrelipase Pancreatitis	Pancreatic enzymes (PERT)	Chronic pancreatitis / CF (PERT)	Replaces lipase/amylase/protease	Abdominal cramps; fibrosing colonopathy (high dose)	Dose ½ at start, ½ mid-meal; non-coated (Viokace) needs PPI
Vitamin K Pancreatitis	Vitamin	Warfarin reversal, liver coagulopathy	Cofactor for factors II, VII, IX, X	Flushing, hypotension	Max IV rate 1 mg/min ⚠ BBW: Anaphylaxis with IV/IM
Entecavir Hepatitis	Nucleoside analog (HBV)	Chronic hepatitis B	Guanosine nucleoside analog — inhibits HBV polymerase	Headache, fatigue	Empty stomach; preferred for HBV monoinfection ⚠ BBW: HBV/HIV exacerbation; lactic acidosis
Tenofovir (TDF/TAF) Hepatitis	Nucleotide RT inhibitor	Chronic HBV (+ HIV)	Nucleotide analog — inhibits reverse transcriptase	TDF: renal (Fanconi), bone loss; TAF: dyslipidemia	TDF preferred for vertical transmission; TAF safer for kidney/bone ⚠ BBW: Post-treatment HBV exacerbation; lactic acidosis
Sofosbuvir Hepatitis	NS5B polymerase inhibitor	Hepatitis C (pangenotypic combos)	NS5B polymerase inhibitor	Fatigue, headache	Amiodarone → severe bradycardia; avoid eGFR<30 ⚠ BBW: HBV reactivation
Ledipasvir/Velpatasvir (-asvir) Hepatitis	NS5A inhibitor	Hepatitis C	NS5A inhibitor — blocks viral assembly	Fatigue, headache	Absorption ↓ by antacids/PPIs ⚠ BBW: HBV reactivation
Glecaprevir/Voxilaprevir (-previr) Hepatitis	NS3/4A protease inhibitor	Hepatitis C	NS3/4A protease inhibitor	Headache, fatigue	CI in decompensated cirrhosis (Child-Pugh B/C) ⚠ BBW: HBV reactivation
Ribavirin Hepatitis	Nucleoside antiviral	Hepatitis C (adjunct)	Inhibits viral RNA synthesis	Hemolytic anemia	Contraception 6–9 mo after; not effective as monotherapy ⚠ BBW: Hemolytic anemia; teratogenicity
Peginterferon alfa-2a Hepatitis	Interferon (immunomodulator)	Select HBV/HCV	Immune modulator	Flu-like, depression, cytopenias	Injectable; largely replaced by DAAs for HCV ⚠ BBW: Neuropsychiatric, autoimmune, ischemic disorders
Linaclotide / Plecanatide IBS/GI	Guanylate cyclase-C agonist	IBS-C, chronic constipation	Guanylate cyclase-C agonist → ↑intestinal fluid	Diarrhea	CI <2 yr (linaclotide) / <6 yr (plecanatide) ⚠ BBW: Serious dehydration in children
Lubiprostone IBS/GI	Chloride channel activator	IBS-C, chronic constipation	Chloride channel activator → ↑secretion	Nausea, diarrhea	Take with food to reduce nausea
Loperamide IBS/GI	Antimotility opioid agonist	Diarrhea, IBS-D	Peripheral mu-opioid agonist — ↓motility	Constipation, QT/torsades (overdose)	Max 48 h; avoid <3 yr ⚠ BBW: Torsades at high doses
Eluxadoline IBS/GI	Mixed opioid modulator	IBS-D	Mixed mu-agonist / delta-antagonist	Constipation, sphincter of Oddi spasm/pancreatitis	CI without a gallbladder; avoid heavy alcohol
Rifaximin IBS/GI	Nonabsorbable antibiotic	IBS-D; hepatic encephalopathy	Nonabsorbable antibiotic	Well tolerated; C. diff	Minimal systemic absorption
Alosetron IBS/GI	5-HT3 antagonist	Severe IBS-D (women)	5-HT3 antagonist	Constipation, ischemic colitis	Reserved for refractory disease; REMS ⚠ BBW: Ischemic colitis, serious constipation
Dicyclomine / Hyoscyamine IBS/GI	Antispasmodic (antimuscarinic)	IBS abdominal pain/cramping	Antimuscarinic — ↓GI motility	Anticholinergic effects	Reverse toxicity with physostigmine
PEG 3350 (MiraLAX) IBS/GI	Osmotic laxative	Chronic constipation	Osmotic laxative — retains water	Bloating, cramps	Preferred for chronic constipation
Lactulose IBS/GI	Osmotic laxative	Constipation; hepatic encephalopathy	Osmotic; colonic bacteria convert NH3→NH4+	Flatulence, cramps, electrolyte loss	Titrate to 2–3 soft stools/day in encephalopathy
Senna / Bisacodyl IBS/GI	Stimulant laxative	Constipation	Stimulant — ↑peristalsis	Cramping, melanosis coli	Short-term; onset 6–12 h (oral)
Docusate IBS/GI	Stool softener	Constipation prevention	Stool softener (surfactant)	Minimal	Best for prevention (post-MI/postpartum/post-op)
PAMORAs (methylnaltrexone/naloxegol) IBS/GI	Peripheral mu-opioid antagonist	Opioid-induced constipation	Peripheral mu-antagonist (gut only)	Abdominal pain, diarrhea, GI perforation	Preserve analgesia; CI GI obstruction
PPIs (omeprazole) IBS/GI	Proton pump inhibitor	GERD, PUD, H. pylori	Irreversibly inhibit H/K-ATPase	B12/iron/Mg deficiency, C. diff, fractures (chronic)	Take before meals
Famotidine (H2 blocker) IBS/GI	H2 antagonist	GERD, PUD	Blocks H2 histamine receptor → ↓acid	Well tolerated	Less potent than PPIs
Misoprostol IBS/GI	Prostaglandin E1	NSAID-ulcer prevention	Prostaglandin E1 analog — ↑mucus/bicarb	Diarrhea, cramping	CI pregnancy (abortifacient)
Metoclopramide IBS/GI	D2 antagonist/prokinetic	Gastroparesis, antiemetic	D2 antagonist — prokinetic	Tardive dyskinesia, EPS	Limit to <12 weeks ⚠ BBW: Tardive dyskinesia
Prednisone / Methylprednisolone Renal/Immuno	Glucocorticoid	ANCA vasculitis, GN, AIN, autoimmune	Glucocorticoid — anti-inflammatory/immunosuppressive	Hyperglycemia, HTN, osteoporosis, infection, Cushingoid	Taper to avoid adrenal crisis; Ca/vit D + PJP prophylaxis
Rituximab Renal/Immuno	Anti-CD20 monoclonal	ANCA vasculitis, immune GN	Anti-CD20 → B-cell depletion	Infusion reactions, infection	Screen HBV; premedicate acetaminophen/antihistamine ⚠ BBW: PML, HBV reactivation, mucocutaneous
Azathioprine Renal/Immuno	Purine antimetabolite	Maintenance immunosuppression	Purine antimetabolite	Myelosuppression, hepatotoxicity	Check TPMT; avoid with allopurinol ⚠ BBW: Malignancy (lymphoma)
Mesna Renal/Immuno	Uroprotectant	With cyclophosphamide/ifosfamide	Binds acrolein in bladder	Nausea	Prevents hemorrhagic cystitis
Levothyroxine (T4) Endo/Thyroid	Thyroid hormone	Hypothyroidism	Synthetic T4 → converted to T3	Overtreatment: AFib, bone loss	Empty stomach, away from Ca/iron; nonpregnant: titrate to TSH q6–8 wk. Pregnancy: ↑dose ~30% at confirmation, TSH q4 wk in T1 and q6 wk in T2–T3, target TSH <2.0 ⚠ BBW: Not for obesity or weight loss; large doses cause serious or fatal toxicity, especially with sympathomimetics
Methimazole Endo/Thyroid	Thioamide	Hyperthyroidism (1st-line)	Inhibits thyroid peroxidase	Rash, arthralgia, agranulocytosis, hepatotoxicity	Avoid first-trimester pregnancy (teratogen)
Propylthiouracil (PTU) Endo/Thyroid	Thioamide	Hyperthyroidism (1st tri, storm)	Inhibits peroxidase + peripheral T4→T3	Agranulocytosis, hepatotoxicity	Preferred in first trimester and thyroid storm ⚠ BBW: Severe hepatotoxicity/liver failure
Potassium iodide (SSKI/Lugol) Endo/Thyroid	Iodide	Thyroid storm; pre-op	Blocks hormone release (Wolff-Chaikoff)	Metallic taste, GI upset	Give ≥1 h AFTER the thionamide
Hydrocortisone Endo/Adrenal	Glucocorticoid	Adrenal insufficiency (replacement)	Gluco+mineralocorticoid receptor agonist	Cushingoid, hyperglycemia, adrenal suppression	2/3 AM, 1/3 PM; stress-dose in illness/surgery
Fludrocortisone Endo/Adrenal	Mineralocorticoid	Mineralocorticoid replacement (Addison)	Aldosterone receptor agonist	Edema, HTN, hypokalemia	Add to hydrocortisone for primary AI
Cosyntropin Endo/Adrenal	Synthetic ACTH	Diagnose adrenal insufficiency	Synthetic ACTH → stimulates cortisol	Rare	Cortisol fails to rise if adrenal failure
Somatropin (GH) Endo/Pituitary	Recombinant growth hormone	GH deficiency / short stature	Recombinant human growth hormone	Arthralgia, edema, ↑glucose	Stop at epiphyseal closure; CI active malignancy, PWI obesity
Octreotide / Lanreotide Endo/Pituitary	Somatostatin analog	Acromegaly, carcinoid, variceal bleed	Somatostatin analog → ↓GH	Gallstones, bradycardia, steatorrhea	Depot dosing q4 wk
Cabergoline / Bromocriptine Endo/Pituitary	Dopamine agonist	Hyperprolactinemia, acromegaly	Dopamine agonist → ↓prolactin	Nausea, orthostasis	First-line (medical) for prolactinoma
Desmopressin Endo/Pituitary	Vasopressin (ADH) analog	Central diabetes insipidus	V2 (ADH) receptor agonist → water retention	Hyponatremia	Also enuresis, vWD/hemophilia A
Alendronate / Risedronate / Zoledronic acid Bone	Bisphosphonate	Osteoporosis (1st-line), Paget	Bisphosphonate — inhibit osteoclasts	Esophagitis, ONJ, atypical femur fracture, hypocalcemia	Empty stomach, upright 30 min; avoid severe renal impairment
Denosumab Bone	RANKL monoclonal	Osteoporosis; hypercalcemia of malignancy	RANKL monoclonal → ↓osteoclast activation	Hypocalcemia, ONJ, infection	SQ q6 mo; do NOT stop abruptly (rebound fractures)
Teriparatide / Abaloparatide Bone	PTH analog (anabolic)	Severe osteoporosis (anabolic)	PTH analog → ↑bone formation	Hypercalcemia, orthostasis	Daily SQ; limit ~2 years ⚠ BBW: Osteosarcoma (rodent)
Romosozumab Bone	Sclerostin inhibitor	Osteoporosis (anabolic)	Sclerostin inhibitor	Injection reaction	Avoid if recent MI/stroke ⚠ BBW: Cardiovascular events (MI/stroke)
Calcitonin Bone	Hormone	Osteoporosis, hypercalcemia	Inhibits osteoclasts	Nasal irritation, nausea	Weak; second-line
Ferrous sulfate (oral iron) Anemia	Oral iron	Iron-deficiency anemia	Replaces iron for hemoglobin synthesis	Constipation, GI upset, dark stools	Ferrous form absorbable; vitamin C aids; separate from antacids/Ca
IV iron (ferric carboxymaltose/iron sucrose/dextran) Anemia	Parenteral iron	Iron deficiency (intolerant/CKD)	Parenteral iron repletion	Hypersensitivity/anaphylaxis (dextran)	Iron dextran needs a test dose; newer agents safer
Folic acid Anemia	Vitamin (B9)	Megaloblastic anemia; pregnancy	Cofactor for DNA synthesis	Rare	Prevents neural tube defects; deficiency: phenytoin, alcohol, MTX
Vitamin B12 (cyanocobalamin) Anemia	Vitamin (B12)	Pernicious/B12-deficiency anemia	Cofactor for DNA synthesis/myelin	Rare	Give WITH folate so folate doesn't mask neuro damage
Epoetin / Darbepoetin (ESAs) Anemia	Erythropoiesis-stimulating agent	Anemia of CKD, chemotherapy	Stimulate erythroid progenitors	Hypertension, thrombosis	Target Hgb ~10–11; replete iron first ⚠ BBW: HTN, thrombosis, ↑mortality/tumor progression
Hydroxyurea Anemia	Antimetabolite	Sickle cell disease	↑Fetal hemoglobin; ribonucleotide reductase inhibitor	Myelosuppression	Reduces vaso-occlusive crizes/acute chest ⚠ BBW: Myelosuppression, malignancy
Thiamine (vitamin B1) Nutrition	Water-soluble vitamin	Alcoholic/starvation ketoacidosis, refeeding syndrome, Wernicke prophylaxis	Cofactor for pyruvate dehydrogenase and transketolase in carbohydrate metabolism	Rare; infusion reactions with IV push	Give BEFORE glucose — a glucose load in a thiamine-deficient patient precipitates Wernicke encephalopathy
Vitamin D (ergocalciferol / cholecalciferol / calcitriol) Nutrition	Vitamin D and analogs	Vitamin D deficiency, hypocalcemia, CKD mineral-bone disease	↑Intestinal calcium and phosphate absorption; calcitriol is the active 1,25-form and needs no renal 1-α-hydroxylation	Hypercalcemia, hyperphosphatemia, hypercalciuria	Replete 25-OH vitamin D first in CKD, then add calcitriol or an analog (paricalcitol, doxercalciferol) once the kidney can no longer activate it; pair with calcium in anyone on an aromatase inhibitor or chronic steroids
Calcium carbonate / calcium citrate Nutrition	Oral calcium salt	Hypocalcemia, supplementation, antacid, phosphate binding	Elemental calcium replacement; also binds dietary phosphate in the gut	Constipation, bloating, hypercalcemia, milk-alkali syndrome	Carbonate needs gastric acid — give with food and expect poor absorption on a PPI; citrate absorbs without acid; separate from levothyroxine, iron, and tetracyclines
Enteral nutrition Nutrition	Nutrition support	Malnutrition or inadequate oral intake with a working gut	Delivers calories, protein, electrolytes, vitamins, and minerals into the GI tract	Aspiration, diarrhea, hyperglycemia, constipation, micronutrient deficiency, refeeding syndrome	Preferred route whenever the gut works; the formula chelates ciprofloxacin and blunts phenytoin absorption — hold feeds around those doses
Parenteral nutrition (TPN) Nutrition	Nutrition support	Intestinal failure or short bowel syndrome when enteral feeding is not feasible	IV dextrose, amino acids, lipid emulsion, electrolytes, vitamins, and trace elements	Catheter-related sepsis, hyperglycemia, electrolyte shifts, hepatic dysfunction, refeeding syndrome	Start low and advance toward goal calories; in underweight patients dose on current weight to avoid refeeding syndrome; follow phosphate, potassium, and magnesium closely as feeding starts
Probiotics (Lactobacillus, Saccharomyces boulardii) Nutrition	Live microbial supplement	Antibiotic-associated and C. difficile diarrhea, acute infectious diarrhea	Restore gut flora, compete with pathogens, and repair intestinal permeability	Bloating, flatulence, hiccups; bacteremia or fungemia in immunocompromized hosts	Continue through the antibiotic course; avoid in the immunosuppressed and in critically ill patients with central access
Albumin / colloids (hetastarch, dextran) Fluids	Colloid volume expander	Large-volume paracentesis, spontaneous bacterial peritonitis, plasmapheresis, hypoalbuminemic diuresis	Colloid stays intravascular and raises plasma oncotic pressure, pulling interstitial fluid into the vessels	Hypersensitivity, bleeding from platelet inhibition and clotting-factor dilution, osmotic nephrosis	Albumin expands volume faster than saline but has shown no mortality benefit; avoid starches and dextrans whenever renal dysfunction is present ⚠ BBW: Hydroxyethyl starch — increased mortality and need for renal replacement therapy in critically ill patients
Mannitol Fluids	Osmotic diuretic	Elevated intracranial pressure; elevated intraocular pressure	Freely filtered and poorly reabsorbed, raising tubular osmolality so water cannot be reabsorbed	Hyponatremia, pulmonary edema, hypovolemia, rebound cerebral edema	Water shifts from cells into the extracellular space first — watch for transient overload; avoid in anuria
Acetazolamide Fluids	Carbonic anhydrase inhibitor	Glaucoma, altitude sickness, metabolic alkalosis from other diuretics	Blocks proximal tubule carbonic anhydrase so bicarbonate is not reabsorbed → osmotic diuresis	Metabolic acidosis, hypokalemia, paresthesias, hypocalcemia	Weak as a diuretic; useful precisely because the acidosis it causes offsets a contraction alkalosis; sulfonamide structure
Hydrochlorothiazide / Chlorthalidone / Indapamide Fluids	Thiazide diuretic	Hypertension, edema, recurrent calcium stones	Block the sodium-chloride cotransporter in the distal convoluted tubule	Hypokalemia, hyponatremia, hypercalcemia, hyperuricemia and gout, hyperglycemia, hyperlipidemia, pancreatitis	Thiazide hyponatremia occurs even without volume depletion because maximal urinary dilution is blocked; thiazides retain calcium while loops waste it; chlorothiazide is the only IV thiazide
Spironolactone / Eplerenone Fluids	Aldosterone antagonist (potassium-sparing)	Cirrhotic ascites, heart failure, hyperaldosteronism; spironolactone off-label for PCOS hirsutism and acne	Competitively block aldosterone at the mineralocorticoid receptor, shutting down ENaC and the Na/K-ATPase pump	Hyperkalemia, metabolic acidosis, gynecomastia and menstrual irregularity (spironolactone)	Preferred diuretic for ascites from liver disease; recheck potassium and creatinine within a week of starting and periodically after; eplerenone is more selective and causes less gynecomastia; avoid in pregnancy
Amiloride / Triamterene Fluids	Epithelial sodium channel blocker	Adjunct to potassium-wasting diuretics; hyperaldosteronism; renal magnesium wasting	Directly block the epithelial sodium channel in the late distal tubule and collecting duct	Hyperkalemia, metabolic acidosis	Weakly natriuretic — used mainly to defend potassium rather than to diurese; amiloride is the diuretic of choice when the kidney is wasting magnesium ⚠ BBW: Hyperkalemia, which can be fatal if uncorrected
Calcium gluconate / Calcium chloride Fluids	IV calcium salt	Symptomatic hypocalcemia; membrane stabilization in hyperkalemia; magnesium toxicity	Restores extracellular ionized calcium and antagonizes the proarrhythmic membrane effects of hyperkalemia	Bradycardia, hypotension, or asystole if infused too fast; tissue necrosis on extravasation	Calcium chloride carries about three times the elemental calcium of gluconate and needs central access; in hyperkalemia it works within 1–2 minutes but lasts only 10–30 minutes — it buys time and does not lower potassium
Potassium binders (sodium polystyrene sulfonate, patiromer, sodium zirconium cyclosilicate) Fluids	Cation exchange resin / binder	Hyperkalemia — definitive lowering of total body potassium	Exchange sodium, calcium, or hydrogen for potassium in the gut lumen so potassium leaves in the stool	Sodium polystyrene: colonic necrosis and perforation; patiromer: hypomagnesemia and GI upset; zirconium cyclosilicate: edema	Patiromer and sodium zirconium cyclosilicate are preferred; reserve sodium polystyrene for life-threatening hyperkalemia when nothing else is available and never give it with sorbitol; separate all of them from other oral drugs by several hours; onset is hours, so this is never the first move in a crashing patient
Sodium bicarbonate Fluids	Alkalinizing agent	Metabolic acidosis of CKD, salicylate toxicity, hyperkalemia with acidosis	Buffers hydrogen ion; alkalinizing the urine ion-traps salicylate and speeds its excretion	Volume overload, hypokalemia, hypocalcemia, metabolic alkalosis	In CKD, oral bicarbonate is titrated to a serum bicarbonate near 22 mEq/L; its potassium-lowering effect is weak and only temporizing
Phosphate binders (sevelamer, lanthanum carbonate, calcium acetate, ferric citrate) Fluids	Phosphate binder	Hyperphosphatemia of chronic kidney disease	Bind dietary phosphate in the gut lumen and block its absorption	Constipation, nausea; calcium-based binders cause hypercalcemia; iron-based binders darken the stool	Must be taken WITH meals or they do nothing; avoid chronic aluminum-based binders; calcium acetate doubles as calcium supplementation but adds to the calcium load
Magnesium (oxide, sulfate) Fluids	Electrolyte	Hypomagnesemia; refractory hypokalemia and hypocalcemia	Cofactor for the Na/K-ATPase; intracellular magnesium normally inhibits ROMK-mediated potassium secretion	Diarrhea limits oral dosing; IV causes flushing, ↓reflexes, and respiratory depression; hypermagnesemia in renal failure	Hypokalemia that will not correct is hypomagnesemia until proven otherwise — replace magnesium first or concurrently; PPIs, loops, thiazides, aminoglycosides, amphotericin B, and cisplatin all waste magnesium; reverse toxicity with IV calcium gluconate
Fomepizole Fluids	Alcohol dehydrogenase inhibitor	Methanol and ethylene glycol poisoning	Competitively inhibits alcohol dehydrogenase so the parent alcohol is not converted to its toxic acid metabolites	Headache, nausea, dizziness, injection-site reaction	Preferred over an ethanol infusion (no intoxication, no glucose swings, predictable dosing); suspect these ingestions when there is a high anion gap AND a high osmolal gap; hemodialysis for severe cases
Scopolamine IBS/GI	Anticholinergic antiemetic	Motion sickness and nausea	Blocks muscarinic acetylcholine receptors in the vestibular apparatus and CNS	Tachycardia, dry mouth, constipation, urinary retention, blurred vision, confusion	Transdermal patch behind the ear; contraindicated in narrow-angle glaucoma and chronic lung disease; wash hands after handling or you get a unilateral dilated pupil
Meclizine / Dimenhydrinate / Hydroxyzine IBS/GI	H1 antihistamine antiemetic	Motion sickness, vertigo, nausea; hydroxyzine also used in interstitial cystitis	Block H1 receptors at the vestibular nucleus; the ones that cross the blood-brain barrier add antimuscarinic blockade	Drowsiness, confusion, blurred vision, constipation, urinary retention	Contraindicated in closed-angle glaucoma, prostatic hypertrophy, and GI obstruction; poor choices in older adults for the same anticholinergic reasons
Promethazine / Prochlorperazine IBS/GI	Phenothiazine (D2 antagonist)	Nausea and vomiting, including migraine-associated nausea	Block dopamine D2 receptors in the chemoreceptor trigger zone	Sedation, acute dystonia and akathisia, QT prolongation, hypotension	Give promethazine IV only dilute and through a free-flowing line; treat acute dystonia with diphenhydramine or benztropine ⚠ BBW: Promethazine — severe tissue injury including gangrene with IV/perivascular administration, and fatal respiratory depression in children under 2. Prochlorperazine — increased mortality in elderly patients with dementia-related psychosis
Aprepitant IBS/GI	NK-1 receptor antagonist	Chemotherapy-induced nausea and vomiting, especially the delayed phase	Blocks substance P at central neurokinin-1 receptors	Fatigue, constipation, hiccups, hypotension, neutropenia, transaminase elevation	Given as part of a triplet with a 5-HT3 antagonist and dexamethasone; a CYP3A4 substrate and inhibitor that can reduce oral contraceptive efficacy; do not combine with pimozide
Dronabinol / Nabilone IBS/GI	Cannabinoid antiemetic	Refractory chemotherapy nausea and vomiting; dronabinol also as an appetite stimulant	Stimulate CB1 receptors and slow GI motility	Dizziness, euphoria, paranoia, hallucinations, tachycardia, cognitive impairment	Useful for anticipatory nausea; may unmask mania, depression, or psychosis; dronabinol capsules are suspended in sesame oil and the oral solution contains alcohol
Sucralfate IBS/GI	Mucosal surface agent	Duodenal and gastric ulcer; GERD in pregnancy	Binds ulcerated mucosa to form a physical barrier, buffers acid, inhibits pepsin, and adsorbs bile salts	Constipation; aluminum accumulation in renal failure	Needs an acid environment, so give on an empty stomach and separate it from PPIs, levothyroxine, fluoroquinolones, and phenytoin; short duration limits it to niche use
Antacids (calcium carbonate, aluminum/magnesium hydroxide) IBS/GI	Antacid	On-demand relief of mild or intermittent GERD and dyspepsia	Chemically neutralize gastric acid already secreted	Aluminum causes constipation and hypophosphatemia; magnesium causes diarrhea; calcium causes rebound acid and hypercalcemia	Relief in about 5 minutes but lasting only 30–60 minutes, and they do not prevent recurrence; they chelate tetracyclines, fluoroquinolones, iron, and levothyroxine
Bismuth subsalicylate / subcitrate IBS/GI	Antisecretory and antimicrobial agent	Traveler's and infectious diarrhea; component of H. pylori quadruple therapy	Antisecretory and topically antimicrobial; the salicylate moiety reduces intestinal secretion	Black tongue and black stools, tinnitus, salicylate toxicity in overdose or renal failure	Avoid with salicylate allergy or other salicylates and in children with a viral illness (Reye syndrome); the black stool is harmless but easily mistaken for melena
Diphenoxylate-atropine IBS/GI	Antimotility opioid	Noninfectious diarrhea not controlled by loperamide	Peripheral opioid agonist slows intestinal transit; subtherapeutic atropine is added to deter abuse	Flushing, tachycardia, dry mouth, confusion, depression; dependence at high doses	Avoid in bloody diarrhea, fever, or suspected C. difficile — slowing the gut worsens invasive infection ⚠ BBW: Not for children under 6 years; overdose causes severe respiratory depression, coma, and death
Clarithromycin (H. pylori therapy) IBS/GI	Macrolide	H. pylori eradication as part of clarithromycin triple therapy with a PPI and amoxicillin	Binds the 50S ribosomal subunit and blocks bacterial protein synthesis	Metallic taste, GI upset, QT prolongation, hepatotoxicity	Use triple therapy only where local clarithromycin resistance is low and there has been no prior macrolide exposure — otherwise use bismuth quadruple therapy; strong CYP3A4 inhibitor; confirm eradication after treating an ulcer
Sulfasalazine / Mesalamine (5-ASA) IBS/GI	Aminosalicylate	Ulcerative colitis; mild Crohn disease	Topical anti-inflammatory action on colonic mucosa; the exact mechanism is unclear	Nausea, dyspepsia, headache, malaise; sulfasalazine adds rash, oligospermia, hemolysis, and folate malabsorption	Supplement folic acid with sulfasalazine; enema and suppository formulations treat distal and rectal disease directly; sulfasalazine is a sulfonamide
Infliximab / Adalimumab (anti-TNF) IBS/GI	TNF-α inhibitor	Moderate to severe Crohn disease and ulcerative colitis	Monoclonal antibodies that bind and neutralize tumor necrosis factor alpha	Infusion and injection-site reactions, infection, transaminase elevation, antinuclear antibodies, demyelination	Screen for latent tuberculosis and hepatitis B before the first dose; infliximab is IV on a loading schedule, adalimumab is subcutaneous; hold during active infection ⚠ BBW: Serious infections including tuberculosis and invasive fungal disease; malignancy including lymphoma
Liothyronine (T3) / Desiccated thyroid Endo/Thyroid	Thyroid hormone	Hypothyroidism — alternative or adjunct to levothyroxine	Supplies T3 directly; desiccated porcine thyroid supplies both T4 and T3	Palpitations, tachycardia, tremor, anxiety, heat intolerance, bone loss	Avoided in known or suspected cardiac disease and not preferred in pregnancy because T3 peaks and lowers T4; equivalence: 100 mcg levothyroxine = 25 mcg liothyronine = 60–65 mg desiccated thyroid (1 grain) ⚠ BBW: Thyroid hormones must not be used for obesity or weight loss; large doses cause serious or fatal toxicity
Propranolol / Atenolol Endo/Thyroid	Beta-blocker	Symptom control in hyperthyroidism and thyroid storm	Blunt adrenergic symptoms; propranolol additionally blocks peripheral conversion of T4 to T3	Bradycardia, bronchospasm, fatigue, masked hypoglycemia	The fastest relief available while a thionamide takes weeks to work; propranolol is the one to reach for in storm because of the conversion block
Insulin — regular and NPH (human insulins) Diabetes	Human insulin	Prandial coverage (regular) and basal coverage (NPH); regular IV for DKA and hyperkalemia	Insulin receptor agonist; NPH is complexed with protamine for intermediate duration	Hypoglycemia, weight gain; NPH has a pronounced mid-dose peak	Only regular insulin can be given IV; NPH's peak forces meals to fit the insulin rather than the reverse; both are safe in renal and hepatic impairment and cost far less than analogs; U-500 regular is five times concentrated
Meglitinides (repaglinide / nateglinide) Diabetes	Insulin secretagogue	Type 2 diabetes, particularly postprandial hyperglycemia	Close the beta-cell K-ATP channel at a site distinct from sulfonylureas → insulin release	Hypoglycemia, weight gain	Short-acting and taken with each meal — skip the dose if the meal is skipped, which makes them useful for irregular eaters and for renal impairment
Liraglutide / Dulaglutide Diabetes	GLP-1 receptor agonist	Type 2 diabetes; liraglutide also approved for weight management	Glucose-dependent insulin release, ↓glucagon, slowed gastric emptying, ↓appetite	Nausea, vomiting, diarrhea, pancreatitis, gallstones, injection-site reaction	Liraglutide, dulaglutide, and semaglutide reduce cardiovascular events; avoid exenatide when eGFR is low and lixisenatide in advanced CKD; no hypoglycemia as monotherapy ⚠ BBW: Thyroid C-cell tumors in rodents — avoid with personal or family history of medullary thyroid carcinoma or MEN2
Ulipristal acetate Contraception	Selective progesterone receptor modulator	Emergency contraception up to 120 hours after intercourse	Blocks and delays the LH surge, postponing ovulation	Headache, nausea, abdominal pain, irregular bleeding	More effective than levonorgestrel later in the 5-day window and at higher body weight; prescription only; wait 5 days before starting or restarting hormonal contraception or it loses effect
Contraceptive patch (norelgestromin) / vaginal ring (etonogestrel) Contraception	Combined hormonal contraceptive	Contraception without daily dosing	Same estrogen-progestin ovulation suppression as the pill, absorbed transdermally or across vaginal mucosa	VTE, MI, stroke, application-site reaction, breakthrough bleeding, vaginal discharge	Carry every estrogen contraindication the pill does; the patch is changed weekly for 3 weeks then a week off, the ring stays in 3 weeks then a week out — both remove the daily-adherence failure mode
Drospirenone-containing COC Contraception	Combined OC with antimineralocorticoid progestin	Contraception; acne; premenstrual dysphoric disorder; hirsutism of PCOS	Drospirenone is a spironolactone analog — antiandrogenic and antimineralocorticoid on top of ovulation suppression	Hyperkalemia, breakthrough bleeding, and possibly higher VTE risk than levonorgestrel-containing pills	Choose it for acne, hirsutism, or PMDD; avoid with renal or adrenal insufficiency or other potassium-raising drugs; levonorgestrel pills carry the lowest VTE risk of the class
Conjugated equine estrogens WH/Menopause	Estrogen	Vasomotor symptoms; IV for acute heavy uterine bleeding; vaginal cream for genitourinary syndrome of menopause	Estrogen receptor agonist replacing declining endogenous estrogen	VTE, stroke, MI, gallbladder disease, melasma, endometrial hyperplasia and cancer if unopposed	Add a progestogen whenever the uterus is intact; use the lowest effective dose and reassess periodically; never prescribe it to prevent cardiovascular disease or dementia; compounded bioidentical preparations and hormone pellets are not FDA approved ⚠ BBW: Endometrial cancer, cardiovascular disorders, breast cancer, and probable dementia
Micronized progesterone (Prometrium) WH/Menopause	Progesterone	Endometrial protection alongside systemic estrogen; inducing a withdrawal bleed	Progesterone receptor agonist opposing estrogen-driven endometrial proliferation	Somnolence, breast tenderness, mood changes, bleeding changes	Chemically distinct from synthetic progestins; suspended in peanut oil, so it is contraindicated in peanut allergy; dose at bedtime because of sedation ⚠ BBW: With estrogen — cardiovascular disorders, breast cancer, and probable dementia
Ospemifene WH/Menopause	SERM	Dyspareunia and vaginal dryness of genitourinary syndrome of menopause	Estrogen receptor agonist at vaginal epithelium, with agonist activity at the endometrium	Hot flashes and night sweats, vaginal discharge, muscle spasms, uterine bleeding, hyperhidrosis	Oral option when vaginal estrogen is declined; may worsen hot flashes; any vaginal bleeding demands endometrial evaluation ⚠ BBW: Endometrial cancer and cardiovascular disorders
Prasterone (Intrarosa) WH/Menopause	Vaginal DHEA	Dyspareunia from vulvovaginal atrophy	Intravaginal dehydroepiandrosterone converted locally to estrogens and androgens in vaginal tissue	Vaginal discharge, abnormal Pap smear	Nightly vaginal insert with minimal systemic exposure; has not been studied in patients with breast cancer
Fezolinetant WH/Menopause	Neurokinin-3 receptor antagonist	Moderate to severe vasomotor symptoms — nonhormonal	Blocks neurokinin-3 signaling on hypothalamic KNDy neurons, resetting thermoregulation	Headache, abdominal pain, insomnia, transaminase elevation	The option when estrogen is contraindicated or refused, including after an estrogen-dependent cancer; check liver enzymes before starting and monitor on therapy; elinzanetant is a newer agent in the same class ⚠ BBW: Hepatotoxicity — rare but serious liver injury
Paroxetine 7.5 mg / Venlafaxine WH/Menopause	SSRI / SNRI for vasomotor symptoms	Hot flashes and night sweats of menopause	Serotonergic and noradrenergic modulation of hypothalamic thermoregulation	Nausea, headache, fatigue, sexual dysfunction, hyponatremia, serotonin syndrome	Low-dose paroxetine is the only FDA-approved nonhormonal SSRI for vasomotor symptoms; never pair paroxetine or fluoxetine with tamoxifen because CYP2D6 inhibition blocks tamoxifen activation — venlafaxine, escitalopram, and citalopram are the safe choices there ⚠ BBW: Suicidal thoughts and behaviors in children, adolescents, and young adults
Tranexamic acid WH	Antifibrinolytic	Acute and chronic heavy menstrual bleeding	Blocks lysine binding sites on plasminogen so plasmin cannot dissolve the clot	GI upset, headache, back pain, arthralgia, thromboembolism	Nonhormonal and taken only on heavy bleeding days; avoid with a thromboembolic history and use caution with combined hormonal contraception; acquired color vision impairment is a contraindication
Elagolix WH	Oral GnRH antagonist	Moderate to severe endometriosis pain, with or without dyspareunia	Competitively blocks the pituitary GnRH receptor for dose-dependent estrogen suppression with no initial flare	Hot flashes, night sweats, amenorrhea, insomnia, mood change, bone mineral density loss, transaminase elevation	Unlike a GnRH agonist there is no testosterone or estrogen flare; treatment duration is capped by bone loss and is shorter at the higher dyspareunia dose; contraindicated in pregnancy, known osteoporosis, and severe hepatic impairment; start within 7 days of menses onset
Ibuprofen / Naproxen WH	NSAID	Dysmenorrhea; adjunct for heavy menstrual bleeding	Inhibit COX so endometrial prostaglandin production falls, reducing uterine cramping and blood loss	GI ulceration and bleeding, renal dysfunction, edema, hypertension, tinnitus	Start at the first sign of menses and dose on a schedule rather than as needed; take with food; contraindicated with aspirin-exacerbated respiratory disease ⚠ BBW: Cardiovascular thrombotic events; GI bleeding, ulceration, and perforation
Acyclovir / Valacyclovir / Famciclovir GU/STI	Nucleoside antiviral	Genital herpes — first episode, episodic recurrence, and chronic suppression	Viral thymidine kinase phosphorylates them, then they inhibit HSV DNA polymerase	Nausea, headache; acyclovir causes crystalluria and nephrotoxicity at high IV doses	They shorten and suppress outbreaks but do not eradicate latent virus or eliminate transmission; valacyclovir is the better-absorbed prodrug; start therapy as early as possible, and begin suppression at 36 weeks of pregnancy to reduce lesions and cesarean delivery at term
Benzathine penicillin G GU/STI	Long-acting penicillin	Syphilis at every stage	Inhibits bacterial cell wall cross-linking	Injection-site pain, hypersensitivity, Jarisch-Herxheimer reaction	2.4 million units IM once for primary, secondary, or early latent disease and weekly for three doses in late latent or unknown duration; the only recommended treatment in pregnancy, so a penicillin-allergic pregnant patient must be desensitized; the Jarisch-Herxheimer fever within 24 hours is spirochete lysis, not allergy; follow RPR titers ⚠ BBW: For deep IM injection only — inadvertent IV administration has caused cardiorespiratory arrest and death
Azithromycin GU/STI	Macrolide	Chlamydia — alternative regimen and the preferred agent in pregnancy	Binds the 50S ribosomal subunit and inhibits bacterial protein synthesis	Nausea, diarrhea, abdominal pain, QT prolongation	1 g PO once, which is useful when adherence is doubtful; doxycycline is preferred in nonpregnant patients; treat partners and avoid intercourse until the treatment interval is complete
Tinidazole GU/STI	Nitroimidazole	Trichomoniasis (alternative), bacterial vaginosis, giardiasis	Reduced inside anaerobes to radicals that damage microbial DNA	Metallic taste, nausea, disulfiram-like reaction with alcohol, peripheral neuropathy	Longer half-life allows a single 2 g dose with a better GI profile than metronidazole, but it is not used in pregnancy or lactation; treat all partners and retest women about 3 months later ⚠ BBW: Carcinogenicity demonstrated in rodents
Clindamycin (vaginal) GU/STI	Lincosamide	Bacterial vaginosis	Binds the 50S ribosomal subunit and inhibits bacterial protein synthesis	Vaginal irritation and candidiasis; C. difficile colitis with systemic exposure	First-line alternative when metronidazole is not tolerated; the cream weakens latex condoms and diaphragms; do not routinely treat male partners for bacterial vaginosis
Topical azoles (miconazole, clotrimazole, terconazole) GU/STI	Azole antifungal	Vulvovaginal candidiasis	Inhibit fungal ergosterol synthesis and disrupt the cell membrane	Local burning and irritation	The treatment of choice in pregnancy — a 7-day topical course rather than oral fluconazole; miconazole and clotrimazole are over the counter, terconazole is prescription; several products weaken latex condoms and diaphragms
Imiquimod GU/STI	Topical immune response modifier	External anogenital warts; actinic keratosis	Toll-like receptor 7 agonist driving local interferon and cytokine release against HPV-infected cells	Erythema, erosion, pain, pruritus, local irritation	Patient-applied overnight and washed off in the morning over weeks; weakens condoms and diaphragms; clinician-applied alternatives include trichloroacetic acid and podophyllin, and podophyllin is contraindicated in pregnancy and in diabetes or poor circulation
Fulvestrant Oncology	Selective estrogen receptor degrader (SERD)	Advanced or metastatic hormone receptor-positive breast cancer	Binds the estrogen receptor and targets it for degradation — a pure antagonist with no agonist activity anywhere	Injection-site pain, hot flashes, transaminase elevation, neutropenia, anemia, VTE	Given as two 5-mL IM injections, one in each buttock, slowly; used alone or with a CDK4/6 inhibitor; caution with anticoagulation or a bleeding disorder; contraception through therapy and for a year after
Exemestane Oncology	Steroidal aromatase inactivator	Postmenopausal hormone receptor-positive breast cancer after 2–3 years of tamoxifen; advanced disease progressing on tamoxifen	Irreversibly inactivates aromatase, unlike the reversible nonsteroidal inhibitors	Hot flashes, arthralgia and joint stiffness, osteoporosis and fracture, hyperhidrosis, transaminase elevation	Not for premenopausal women unless the ovaries are suppressed; never give with an estrogen-containing product; check a baseline vitamin D level, supplement calcium and vitamin D, and monitor bone density
Testosterone (cypionate, enanthate, undecanoate, gel, patch) ED	Androgen	Symptomatic testosterone deficiency confirmed on two morning total testosterone measurements	Androgen receptor agonist acting on hormone response elements → lean body mass, libido, mood, bone density	Polycythemia, acne, edema, worsened sleep apnea, oligospermia, gynecomastia, male pattern baldness, prostate stimulation	Measure PSA before starting in men over 40 and evaluate any elevation first; monitor hematocrit and stop or reduce if it climbs; check a total testosterone about 4 weeks after starting and then periodically; injections give supraphysiologic peaks and troughs while gels and patches run steadier; suppresses spermatogenesis, so refer men who want fertility ⚠ BBW: Topical gels — secondary exposure causing virilization in women and children
Papaverine / Phentolamine ED	Intracavernosal vasodilators	Erectile dysfunction when PDE5 inhibitors fail or are contraindicated	Papaverine is a nonspecific phosphodiesterase inhibitor and phentolamine an α-blocker — both relax cavernosal smooth muscle	Priapism, penile pain, corporal fibrosis, hypotension	Used together, often with alprostadil, as bimix or trimix; alprostadil alone remains first-line because it causes less fibrosis and priapism; the first dose is titrated in the office; contraindicated in sickle cell disease
Pentosan polysulfate sodium UTI/OAB	Semisynthetic heparin-like polysaccharide	Interstitial cystitis / bladder pain syndrome	Thought to rebuild the glycosaminoglycan layer lining the bladder urothelium	Dyspepsia, nausea, anorexia, alopecia; pigmentary maculopathy with prolonged use	100 mg orally three times daily and the only oral drug approved for this indication, though randomized trials show benefit no better than placebo; get baseline and periodic retinal exams
OnabotulinumtoxinA (intravesical) UTI/OAB	Neurotoxin	Refractory overactive bladder, neurogenic detrusor overactivity, interstitial cystitis	Blocks release of acetylcholine and other neurotransmitters from urothelium and nerve fibers, damping afferent and efferent signaling	Urinary retention requiring self-catheterization, UTI, hematuria	Reserved for failure of antimuscarinics and beta-3 agonists; only offer it to a patient willing and able to self-catheterize; effect wears off in months ⚠ BBW: Distant spread of toxin effect — swallowing and breathing difficulties can be life threatening