| Indication | Used in cardiovascular disease to treat arrhythmias, angina pectoris, and hypertension. |
| Pharmacodynamics | Nadolol is a nonselective beta-adrenergic receptor antagonist with a long half-life, and is structurally similar to propranolol. Clinical pharmacology studies have demonstrated beta-blocking activity by showing (1) reduction in heart rate and cardiac output at rest and on exercise, (2) reduction of systolic and diastolic blood pressure at rest and on exercise, (3) inhibition of isoproterenol-induced tachycardia, and (4) reduction of reflex orthostatic tachycardia. Nadolol has no intrinsic sympathomimetic activity and, unlike some other beta-adrenergic blocking agents, nadolol has little direct myocardial depressant activity and does not have an anesthetic-like membrane-stabilizing action. |
| Mechanism of action | Like other beta-adrenergic antagonists, nadolol competes with adrenergic neurotransmitters such as catecholamines for binding at sympathetic receptor sites. Like propranolol and timolol, nadolol binds at beta(1)-adrenergic receptors in the heart and vascular smooth muscle, inhibiting the effects of the catecholamines epinephrine and norepinephrine and decreasing heart rate, cardiac output, and systolic and diastolic blood pressure. It also blocks beta-2 adrenergic receptors located in bronchiole smooth muscle, causing vasoconstriction. By binding beta-2 receptors in the juxtaglomerular apparatus, nadolol inhibits the production of renin, thereby inhibiting angiotensin II and aldosterone production. Nadolol therefore inhibits the vasoconstriction and water retention due to angiotensin II and aldosterone, respectively. |
| Absorption | Absorption of nadolol after oral dosing is variable, averaging about 30 percent. |
| Volume of distribution | Not Available |
| Protein binding | 30% |
| Metabolism | Not metabolized by the liver and excreted unchanged primarily by the kidneys. |
| Route of elimination | Unlike many other beta-adrenergic blocking agents, nadolol is not metabolized by the liver and is excreted unchanged, principally by the kidneys. Nadolol is excreted predominantly in the urine. |
| Half life | 14-24 hours |
| Clearance | Not Available |
| Toxicity | Oral, mouse: LD50 = 4500mg/kg. Symptoms of overdose include abdominal irritation, central nervous system depression, coma, extremely slow heartbeat, heart failure, lethargy, low blood pressure, and wheezing. |