SPECIFIC BETA BLOCKER DRUGS Metabolized in liver excreted via kidneys Prototype

Specific beta blocker drugs metabolized in liver

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SPECIFIC BETA BLOCKER DRUGS: Metabolized in liver, excreted via kidneys Prototype: Propranolol (Inderal) Inderal is the oldest beta blocker Non-Selective: blocks both beta 1 (cardiac) and beta 2 (smooth muscle in bronchi and blood vessels) Used for: HTN, arrhythmias, angina, MI, cardiomyopathies, pheochromocytoma, hyperthyroidism, prevention of migraines
CARDIO SELECTIVE BETA BLOCKERS (MORE EFFECTS ON BETA 1 THAN BETA 2 IN THEORY) The selectivity may be lost at higher drug doses because most organs have both receptor sites Drugs in this category include: Atenolol (tenormin): HTN, angina, MI Esmolol (brevibloc): arrythmias Metoprolol (lopressor): HTN, MI
BETA BLOCKERS THAT EFFECT ALPHA 1 AND BETA 1,2 Some block alpha 1 (cause vasodilation) Some block beta 1 and beta 2 receptors (all non selective effects) Less bradycardia and less tachycardia than other vasodilators Labetalol (Normodyne): used in HTN Hypertensive emergencies
GENERAL INFORMATION (BETA BLOCKERS) Do not stop abruptly : May cause a rebound hypertension May cause or aggravate angina Risk of arrhythmias Taper over 1-2 weeks may cause bradycardia may cause impotence in men
GENERAL INFORMATION (BETA BLOCKERS) Treating adverse effects of beta blockers: atropine for bradycardia digoxin and diuretics for CHF bronchodilators for bronchoconstriction Usually stopped before surgery due to the fact myocardial depressants are increased by general anesthesia Doses may need to be decreased in renal or hepatic disease Beta blockers alone generally not effective in Blacks. A multi- drug regimen is required Asians usually need smaller doses than whites Adverse effects are more common in the elderly and doses may need to be smaller Educate patients well: patient may experience fatigue and dizziness and often quit taking them
CHOLINERGIC DRUGS
CHOLINERGIC DRUGS Parasympathomimetics Cholinomimetics Stimulate the PNS the same way acetylcholine does Effects of drugs last longer than endogenous acetylcholine
EFFECTS OF CHOLINERGIC DRUGS: Decreased HR Vasodilation Increased tone and contractility of GI smooth muscle, relaxation of GI sphincters and increased GI secretions Increased tone and contractility of smooth muscle of the bladder and relaxation of bladder sphincter Increased tone and contractility of bronchial smooth muscle Increased respiratory secretions Pupil constriction
CHOLINERGICS: CONTRAINDICATIONS Urinary obstruction GI obstruction Asthma Peptic Ulcer Disease (PUD) Coronary Artery Disease (CAD) Hyperthyroidism
MUSCARINIC AGONISTS Bethanechol “Parasympathomimetic agent” Selective agonist at muscarinic cholinergic receptors Heart: Bradycardia Smooth muscle: Lung: Constriction of the bronchi Gastrointestinal system: Increased tone and motility Bladder: Contraction of detrusor muscle and relaxation of the trigone and sphincter Exocrine glands: Increased sweating, salivation, bronchial secretions, and secretion of gastric acid 59
MUSCARINIC AGONISTS Bethanechol

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