Pharmacology Review – GI, GU, Endocrine, CNS & Related Agents

Vocabulary flashcards summarizing key pharmacological terms, drug classes, mechanisms, uses, and cautions from the lecture notes.

Antacids

Basic compounds (aluminum, magnesium, calcium, sodium salts) that neutralize gastric acid; relieve heartburn, PUD; may cause constipation (Al/Ca) or diarrhea (Mg).

Simethicone

Antiflatulent often combined with antacids to reduce gas and bloating.

Rebound Hyperacidity

Return of stomach acid secretion above baseline after discontinuing calcium-containing antacids.

H2 Receptor Antagonists (H2RAs)

Cimetidine, famotidine, nizatidine; block histamine-2 receptors on parietal cells, ↓ acid up to 90%.

Cimetidine

First H2RA; inhibits CYP-450, ↑ drug interactions; higher risk of adverse effects in elderly.

Proton Pump Inhibitors (PPIs)

Omeprazole, pantoprazole, etc.; irreversibly inhibit gastric H⁺/K⁺-ATPase, block all acid secretion.

Clostridium difficile Risk

Long-term, high-dose PPI use linked to C. difficile infection, fractures, hypomagnesemia.

Sucralfate

Cytoprotective agent that binds ulcer base, forms barrier against acid and pepsin.

Misoprostol

Prostaglandin analog that prevents NSAID-induced ulcers by inhibiting gastric acid secretion.

Adsorbents (Antidiarrheals)

Agents like bismuth subsalicylate; coat GI tract and bind toxins; may cause black tongue/stools.

Opiate Antidiarrheals

Loperamide, diphenoxylate; decrease bowel motility and relieve rectal spasms.

Probiotics

Live Lactobacillus cultures that restore normal intestinal flora and suppress pathogens.

Bulk-Forming Laxatives

Psyllium, methylcellulose; absorb water to form viscous gel, promoting peristalsis—safest long-term.

Emollient Laxatives

Stool softeners (docusate) and lubricants (mineral oil) that ease fecal passage by adding water/fat.

Hyperosmotic Laxatives

Lactulose, polyethylene glycol; draw water into colon, causing distention and evacuation.

Saline Laxatives

Magnesium citrate, milk of magnesia; osmotic action draws water into bowel, rapid watery stool.

Stimulant Laxatives

Senna, bisacodyl; stimulate enteric nerves to increase peristalsis; may cause cramping.

Irritable Bowel Syndrome (IBS)

Chronic abdominal pain with diarrhea (IBS-D) or constipation (IBS-C); treated with targeted drugs such as alosetron, rifaximin, lubiprostone.

Alosetron

5-HT₃ antagonist for severe IBS-D in women; carries ischemic colitis black-box warning.

Ondansetron

Serotonin (5-HT₃) antagonist used to prevent chemotherapy-induced nausea/vomiting.

Metoclopramide

Prokinetic dopamine antagonist; ↑ GI motility, antiemetic; risk of tardive dyskinesia with long use.

Scopolamine

Anticholinergic patch preventing motion sickness; contraindicated in narrow-angle glaucoma.

Loop Diuretics

Furosemide, bumetanide; inhibit Na⁺/Cl⁻ resorption in loop of Henle; potent diuresis; risk hypokalemia, ototoxicity.

Thiazide Diuretics

Hydrochlorothiazide; inhibit Na⁺/Cl⁻ resorption in distal tubule; first-line for hypertension.

Potassium-Sparing Diuretics

Spironolactone, amiloride; antagonize aldosterone in distal nephron, retain K⁺, risk hyperkalemia.

Mannitol

Osmotic diuretic; reduces intracranial pressure, prevents renal failure; may cause pulmonary edema.

Crystalloids

IV solutions (NS, LR) containing water and electrolytes, no proteins; quickly distribute into tissues.

Colloids

Protein-containing IV fluids (albumin, dextran) that expand plasma volume by raising oncotic pressure.

Hyperkalemia

Serum K⁺ > 5.5 mEq/L; causes muscle weakness, arrhythmias; treated with patiromer, insulin + glucose, etc.

Hyponatremia

Serum Na⁺ < 135 mEq/L; symptoms include lethargy, seizures; vaptans (conivaptan, tolvaptan) used in euvolemic cases.

Digoxin

Cardiac glycoside; positive inotrope for HF and AF; narrow therapeutic index, toxicity with hypokalemia.

ACE Inhibitors

Lisinopril, enalapril; block conversion of Ang I to Ang II; beneficial in HF, hypertension; dry cough common.

Angiotensin II Receptor Blockers (ARBs)

Losartan, valsartan; block Ang II receptors; used when ACEI not tolerated (no cough).

Beta Blockers in HF

Carvedilol, metoprolol; block sympathetic stimulation, reduce mortality in heart failure.

Phosphodiesterase Inhibitor (Milrinone)

Inodilator increasing cAMP; short-term IV therapy for acute decompensated HF; risk dysrhythmias.

Amiodarone

Class III antidysrhythmic; prolongs repolarization; black-box for pulmonary/hepatic toxicity.

Warfarin Interaction

Many antidysrhythmics (e.g., amiodarone) potentiate warfarin, requiring INR monitoring.

Alpha-1 Blockers (Doxazosin)

Peripheral vasodilators for hypertension; first-dose syncope due to orthostatic hypotension.

Clonidine

Central alpha-2 agonist antihypertensive; abrupt withdrawal causes rebound hypertension.

Nitrates

Nitroglycerin, isosorbide dinitrate; release NO causing venous > arterial dilation; treat angina; risk tolerance.

Calcium Channel Blockers

Amlodipine, diltiazem; inhibit Ca²⁺ entry in vascular smooth muscle; treat HTN, angina, dysrhythmias.

Statins (HMG-CoA Reductase Inhibitors)

Atorvastatin, simvastatin; ↓ LDL synthesis; myopathy/rhabdomyolysis rare but serious adverse effect.

PCSK-9 Inhibitors

Alirocumab, evolocumab; monoclonal antibodies that dramatically lower LDL-C when added to statins.

Niacin

Vitamin B₃; lowers triglycerides, raises HDL; causes flushing mitigated by aspirin pre-dose.

Sulfonylureas

Glipizide, glyburide; stimulate pancreatic insulin release; risk hypoglycemia, weight gain.

Biguanide (Metformin)

↓ hepatic gluconeogenesis, ↑ insulin sensitivity; first-line T2DM; contraindicated if eGFR < 30 mL/min.

DPP-4 Inhibitors

Sitagliptin et al.; prevent incretin breakdown, ↑ insulin, ↓ glucagon; risk pancreatitis.

GLP-1 Agonists

Exenatide, liraglutide; injectable incretin mimetics slowing gastric emptying, promoting weight loss.

SGLT2 Inhibitors

Canagliflozin, empagliflozin; block renal glucose reabsorption; benefits CV, but risk ketoacidosis, genital infections.

Rapid-Acting Insulin

Lispro, aspart; onset ~15 min; give within 15 min of meal to avoid hypoglycemia.

Basal-Bolus Regimen

Long-acting insulin (glargine) for baseline + rapid-acting for meals/corrections—preferred inpatient control.

Phenytoin

Hydantoin antiepileptic; stabilizes neuronal membranes; narrow therapeutic range; causes gingival hyperplasia.

Valproic Acid

Broad-spectrum antiepileptic; hepatotoxicity and pancreatitis black-box warnings.

Levodopa/Carbidopa

Dopamine precursor + dopa-decarboxylase inhibitor to cross BBB and treat Parkinson’s; long-term dyskinesias.

COMT Inhibitors

Entacapone, tolcapone; block levodopa breakdown; tolcapone hepatotoxic (black-box).

Benzodiazepines

Diazepam, lorazepam; enhance GABA; anxiolytic, sedative; risk dependence, CNS depression—avoid with alcohol.

Zolpidem

Non-benzodiazepine hypnotic for insomnia; less REM suppression; risk sleep-walking behaviors.

Amphetamines

CNS stimulants (Adderall) for ADHD/narcolepsy; increase NE/DA release; Schedule II; insomnia, weight loss.

Methylphenidate

Ritalin/Concerta; mild CNS stimulant structurally like amphetamine used in ADHD.

Triptons

Sumatriptan et al.; 5-HT₁B/1D agonists abort migraine via cranial vasoconstriction; contraindicated in CAD.

Alendronate

Oral bisphosphonate; inhibits osteoclasts; sit upright 30 min post-dose to prevent esophagitis.

Raloxifene

SERM acting as estrogen agonist in bone, antagonist in breast/uterus; prevents osteoporosis; risk DVT.

Finasteride

5-Alpha reductase inhibitor for BPH and male baldness; teratogenic—pregnant women avoid handling tablets.

Sildenafil

PDE-5 inhibitor for erectile dysfunction; contraindicated with nitrates due to severe hypotension.

Oxytocin

Posterior pituitary hormone; induces/enhances labor, controls postpartum hemorrhage.

Terbutaline

Beta-agonist tocolytic (rare use) delaying preterm labor; maternal tachycardia limits use.

Clomiphene

Selective estrogen receptor modulator that induces ovulation by ↑ FSH/LH secretion.

Bisacodyl

Stimulant laxative; enteric-coated—must not be taken with milk/antacids which dissolve coating.