The mechanism of the antihypertensive effect of propranolol has not been established. Factors that may contribute to the antihypertensive action include:
1) decreased cardiac output, inhibition of renin release by the kidneys, and diminution of tonic sympathetic nerve outflow from vasomotor centers in the brain. Although total peripheral resistance may increase initially, it readjusts to or below the pretreatment level with chronic use of propranolol. Effects of propranolol on plasma volume appears to be minor and somewhat variable. See package insert for complete information.

Hypertension: Inderal is indicated in the management of hypertension. It may be used alone or used in combination with other antihypertensive agents, particularly a thiazide diuretic. Inderal is not indicated in the management of hypertensive emergencies. Angina Pectoris Due to Coronary Atherosclerosis: Inderal is indicated to decrease angina frequency and increase exercise tolerance in patients with angina pectoris. Atrial Fibrillation: Inderal is indicated to control ventricular rate in patients with atrial fibrillation and a rapid ventricular response. See package insert for complete information.

Because of the variable bioavailability of propranolol, the dose should be individualized based on response. See package insert for complete information.

Cardiovascular: Bradycardia; congestive heart failure; intensification of AV block; hypotension; paresthesia of hands; thrombocytopenic purpura; arterial insufficiency, usually of the Raynaud type. Central Nervous System: Light-headedness, mental depression manifested by insomnia, lassitude, weakness, fatigue; catatonia; visual disturbances; hallucinations; vivid dreams; an acute reversible syndrome characterized by disorientation for time and place, short-term memory loss, emotional lability, slightly clouded sensorium, and decreased performance on neuropsychometrics. For immediate-release formulations, fatigue, lethargy, and vivid dreams appear dose-related. See package insert for complete information.

Propranolol is contraindicated in
1) cardiogenic shock;
2) sinus bradycardia and greater than first degree block;
3) bronchial asthma; and
4) in patients with known hypersensitivity to propranolol hydrochloride.

Propranolol should be used with caution in patients with impaired hepatic or renal function. Inderal is not indicated for the treatment of hypertensive emergencies. Beta-adrenergic receptor blockade can cause reduction of intraocular pressure. Patients should be told that Inderal may interfere with the glaucoma screening test. Withdrawal may lead to a return of increased intraocular pressure. While taking beta blockers, patients with a history of severe anaphylactic reaction to a variety of allergens may be more reactive to repeated challenge, either accidental, diagnostic, or therapeutic. Such patients may be unresponsive to the usual doses of epinephrine used to treat allergic reaction.