These confirm no contradiction with standard teaching (they're niche applications - Takotsubo, dialysis-related HTN, portal HTN variceal prophylaxis - all consistent with/supportive of textbook uses). Now here's the exam answer.

Beta blockers competitively antagonize catecholamines at β1 (cardiac) and/or β2 (bronchial, vascular, metabolic) adrenoceptors. Their clinical uses span cardiovascular, ophthalmic, neuropsychiatric, endocrine, and other systems.

1. Hypertension All β blockers lower BP in mild-moderate hypertension, mainly by reducing cardiac output and inhibiting renin release (β1-mediated). Especially useful when combined with direct vasodilators (prevents reflex tachycardia) and in patients with coexisting angina or prior MI - Katzung's Basic and Clinical Pharmacology, p. 288.

2. Angina Pectoris Reduce heart rate, contractility, and BP, thereby decreasing myocardial oxygen demand and improving exercise tolerance in effort angina. Combined with nitrates/calcium channel blockers for better control - Katzung's Basic and Clinical Pharmacology.

3. Cardiac Arrhythmias Used for supraventricular tachyarrhythmias (atrial fibrillation/flutter - rate control), and to suppress ventricular ectopy, especially those due to increased sympathetic activity (e.g., post-MI, exercise-induced, thyrotoxic arrhythmias). Sotalol has additional class III antiarrhythmic action - Symptom to Diagnosis, An Evidence-Based Guide.

4. Post-Myocardial Infarction Reduce mortality and reinfarction risk when started early and continued long-term after MI (reduce myocardial oxygen demand, arrhythmia risk).

5. Heart Failure (HFrEF) Carvedilol, metoprolol succinate, and bisoprolol reduce mortality and hospitalization in chronic systolic heart failure by blunting the deleterious effects of chronic sympathetic activation - Braunwald's Heart Disease.

6. Hypertrophic Obstructive Cardiomyopathy Reduce the dynamic outflow obstruction and improve symptoms of dyspnea/angina by decreasing contractility and heart rate - Braunwald's Heart Disease.

7. Dissecting Aortic Aneurysm / Marfan syndrome Reduce the rate of aortic dilatation by lowering the force and rate of ventricular ejection (dP/dt).

8. Glaucoma Topical timolol, betaxolol, and levobunolol reduce intraocular pressure by decreasing aqueous humor production (ciliary body β-receptors), without affecting pupil size or accommodation.

9. Migraine Prophylaxis Propranolol is a first-line agent for chronic migraine prevention - Katzung's Basic and Clinical Pharmacology.

10. Thyrotoxicosis Propranolol rapidly controls adrenergic symptoms - tachycardia, tremor, anxiety, palpitations - and inhibits peripheral T4-to-T3 conversion; also used in thyroid storm.

11. Anxiety / Essential Tremor / Performance Anxiety Propranolol reduces somatic symptoms of anxiety (tachycardia, tremor, sweating) and benign essential tremor.

12. Pheochromocytoma Used as adjunct (after adequate alpha-blockade) to control tachycardia and arrhythmias; never given alone as unopposed alpha-mediated vasoconstriction can precipitate hypertensive crisis.

13. Portal Hypertension / Variceal Bleeding Prophylaxis Non-selective agents (propranolol, nadolol, carvedilol) reduce portal pressure and the risk of first variceal bleed and rebleeding in cirrhotic patients.

14. Migraine, Akathisia, and Alcohol/Opioid Withdrawal Propranolol reduces autonomic hyperactivity symptoms.

15. Perioperative/Anesthesia Esmolol (ultra-short-acting) used for acute intraoperative control of heart rate and BP, and to blunt the pressor response to laryngoscopy/intubation - Barash's Clinical Anesthesia.

16. Others Prophylaxis of upper GI bleeding in cirrhosis, adjunct in infantile hemangioma (propranolol), and stage fright/public speaking anxiety.

Note: These are well-established uses per current pharmacology and cardiology textbooks; recent systematic reviews (2024-2025) continue to support beta-blocker efficacy in related niche indications such as Takotsubo cardiomyopathy, dialysis-associated hypertension, and portal hypertension (PMIDs: 41173513, 38424373, 38285880), consistent with standard teaching.