Overview
DESCRIPTION Propranolol hydrochloride, USP is a synthetic beta-adrenergic receptor blocking agent chemically described as 2-Propanol, 1-[(1-methylethyl)amino]-3-(1-naphthalenyloxy)-, hydrochloride,(±)-. Its structural formula is: Propranolol hydrochloride, USP is a stable, white to off-white, crystalline powder which is readily soluble in water and ethanol.
Mechanism of Action
CLINICAL PHARMACOLOGY General Propranolol is a nonselective beta-adrenergic receptor blocking agent possessing no other autonomic nervous system activity. It specifically competes with beta-adrenergic receptor agonist agents for available receptor sites. When access to beta-receptor sites is blocked by propranolol, the chronotropic, inotropic, and vasodilator responses to beta-adrenergic stimulation are decreased proportionately. At dosages greater than required for beta blockade, propranolol also exerts a quinidine-like or anesthetic-like membrane action, which affects the cardiac action potential. The significance of the membrane action in the treatment of arrhythmias is uncertain. Mechanism of Action The mechanism of the antihypertensive effect of propranolol has not been established.
Indications
- INDICATIONS AND USAGE Hypertension Propranolol hydrochloride tablets are indicated in the management of hypertension. It may be used alone or used in combination with other antihypertensive agents, particularly a thiazide diuretic. Propranolol hydrochloride is not indicated in the management of hypertensive emergencies. Angina Pectoris Due to Coronary Atherosclerosis Propranolol hydrochloride tablets are indicated to decrease angina frequency and increase exercise tolerance in patients with angina pectoris.
Common Doses
- 40 mg
- 120 mg
- 240 mg
- 640 mg
Dosage
DOSAGE AND ADMINISTRATION General Because of the variable bioavailability of propranolol, the dose should be individualized based on response. Hypertension The usual initial dosage is 40 mg propranolol hydrochloride twice daily, whether used alone or added to a diuretic. Dosage may be increased gradually until adequate blood pressure control is achieved. The usual maintenance dosage is 120 mg/day to 240 mg per day. In some instances a dosage of 640 mg a day may be required.
Contraindications
- CONTRAINDICATIONS 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.
Side Effects
- ADVERSE REACTIONS The following adverse events were observed and have been reported in patients using propranolol. 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,...
Interactions
- Drug Interactions Caution should be exercised when propranolol is administered with drugs that have an effect on CYP2D6, 1A2, or 2C19 metabolic pathways. Co-administration of such drugs with propranolol may lead to clinically relevant drug interactions and changes on its efficacy and/or toxicity (see Drug Interactions in PHARMACOKINETICS AND DRUG METABOLISM ). Cardiovascular Drugs Antiarrhythmics Propafenone has negative inotropic and beta-blocking properties that can be additive to those of propranolol.