propranolol hydrochloride

INDICATIONS AND USAGE Hypertension Propranolol Hydrochloride Extended-Release Capsules, USP, are indicated in the management of hypertension. They may be used alone or used in combination with other antihypertensive agents, particularly a thiazide diuretic. Propranolol Hydrochloride Extended-Release Capsules, USP, are not indicated in the management of hypertensive emergencies. Angina Pectoris Due to Coronary Atherosclerosis Propranolol Hydrochloride Extended-Release Capsules, USP, are indicated to decrease angina frequency and increase exercise tolerance in patients with angina pectoris. Migraine Propranolol Hydrochloride Extended-Release Capsules, USP, are indicated for the prophylaxis of common migraine headache. The efficacy of propranolol in the treatment of a migraine attack that has started has not been established, and propranolol is not indicated for such use. Hypertrophic Subaortic Stenosis Propranolol Hydrochloride Extended-Release Capsules, USP, improve NYHA functional class in symptomatic patients with hypertrophic subaortic stenosis.

DOSAGE AND ADMINISTRATION General Propranolol Hydrochloride Extended-Release Capsules, USP, provide propranolol hydrochloride in a sustained-release capsule for administration once daily. If patients are switched from propranolol hydrochloride tablets to Propranolol Hydrochloride Extended-Release Capsules, USP, care should be taken to assure that the desired therapeutic effect is maintained. Propranolol Hydrochloride Extended-Release Capsules, USP, should not be considered a simple mg-for-mg substitute for propranolol hydrochloride tablets. Propranolol Hydrochloride Extended-Release Capsules, USP, have different kinetics and produces lower blood levels. Retitration may be necessary, especially to maintain effectiveness at the end of the 24-hour dosing interval. Hypertension The usual initial dosage is 80 mg Propranolol Hydrochloride Extended-Release Capsules, USP, once daily, whether used alone or added to a diuretic. The dosage may be increased to 120 mg once daily or higher until adequate blood pressure control is achieved. The usual maintenance dosage is 120 to 160 mg once daily. In some instances a dosage of 640 mg may be required. The time needed for full hypertensive response to a given dosage is variable and may range from a few days to several weeks. Angina Pectoris Starting with 80 mg Propranolol Hydrochloride Extended-Release Capsules, USP, once daily, dosage should be gradually increased at three- to seven-day intervals until optimal response is obtained. Although individual patients may respond at any dosage level, the average optimal dosage appears to be 160 mg once daily. In angina pectoris, the value and safety of dosage exceeding 320 mg per day have not been established. If treatment is to be discontinued, reduce dosage gradually over a period of a few weeks (see WARNINGS ). Migraine The initial oral dose is 80 mg Propranolol Hydrochloride Extended-Release Capsules, USP, once daily. The usual effective dose range is 160 to 240 mg once daily. The dosage may be increased gradually to achieve optimal migraine prophylaxis. If a satisfactory response is not obtained within four to six weeks after reaching the maximal dose, Propranolol Hydrochloride Extended-Release Capsules, USP, therapy should be discontinued. It may be advisable to withdraw the drug gradually over a period of several weeks depending on the patient's age, comorbidity, and dose of Propranolol Hydrochloride Extended-Release Capsules, USP. Hypertrophic Subaortic Stenosis The usual dosage is 80 to 160 mg Propranolol Hydrochloride Extended-Release Capsules, USP, once daily.

Mechanism of Action The mechanism of the antihypertensive effect of propranolol has not been established. Among the factors that may be involved in contributing to the antihypertensive action include: 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 appear to be minor and somewhat variable. In angina pectoris, propranolol generally reduces the oxygen requirement of the heart at any given level of effort by blocking the catecholamine-induced increases in the heart rate, systolic blood pressure, and the velocity and extent of myocardial contraction. Propranolol may increase oxygen requirements by increasing left ventricular fiber length, end diastolic pressure, and systolic ejection period. The net physiologic effect of beta-adrenergic blockade is usually advantageous and is manifested during exercise by delayed onset of pain and increased work capacity. Propranolol exerts its antiarrhythmic effects in concentrations associated with beta-adrenergic blockade, and this appears to be its principal antiarrhythmic mechanism of action. In 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. The mechanism of the anti-migraine effect of propranolol has not been established. Beta-adrenergic receptors have been demonstrated in the pial vessels of the brain.

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, emotional lability, slightly clouded sensorium, and decreased performance on neuropsychometrics. For immediate release formulations, fatigue, lethargy, and vivid dreams appear dose related. Gastrointestinal: Nausea, vomiting, epigastric distress, abdominal cramping, diarrhea, constipation, mesenteric arterial thrombosis, ischemic colitis. Allergic: Hypersensitivity reactions, including anaphylactic/anaphylactoid reactions; pharyngitis and agranulocytosis; erythematous rash; fever combined with aching and sore throat; laryngospasm; respiratory distress. Respiratory: Bronchospasm. Hematologic: Agranulocytosis, nonthrombocytopenic purpura, thrombocytopenic purpura. Autoimmune: Systemic lupus erythematosus (SLE). Skin and Mucous Membranes: Stevens-Johnson Syndrome, toxic epidermal necrolysis, dry eyes, exfoliative dermatitis, erythema multiforme, urticaria, alopecia, SLE-like reactions, and psoriasiform rashes. Oculomucocutaneous syndrome involving the skin, serous membranes, and conjunctivae reported for a beta-blocker (practolol) have not been associated with propranolol. Genitourinary: Male impotence; Peyronie's disease.

Drug Interactions Caution should be exercised when Propranolol Hydrochloride Extended-Release Capsules, USP, are administered with drugs that have an affect 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 ). Alcohol when used concomitantly with propranolol, may increase plasma levels of propranolol. Cardiovascular Drugs Antiarrhythmics Propafenone has negative inotropic and beta-blocking properties that can be additive to those of propranolol. Quinidine increases the concentration of propranolol and produces greater degrees of clinical beta-blockade and may cause postural hypotension. Amiodarone is an antiarrhythmic agent with negative chronotropic properties that may be additive to those seen with β-blockers such as propranolol. The clearance of lidocaine is reduced with administration of propranolol. Lidocaine toxicity has been reported following co-administration with propranolol. Caution should be exercised when administering Propranolol Hydrochloride Extended-Release Capsules, USP, with drugs that slow A-V nodal conduction, e.g., lidocaine and calcium channel blockers. Digitalis Glycosides Both digitalis glycosides and beta-blockers slow atrioventricular conduction and decrease heart rate. Concomitant use can increase the risk of bradycardia. Calcium Channel Blockers Caution should be exercised when patients receiving a beta-blocker are administered a calcium-channel-blocking drug with negative inotropic and/or chronotropic effects. Both agents may depress myocardial contractility or atrioventricular conduction. There have been reports of significant bradycardia, heart failure, and cardiovascular collapse with concurrent use of verapamil and beta-blockers. Co-administration of propranolol and diltiazem in patients with cardiac disease has been associated with bradycardia, hypotension, high degree heart block, and heart failure. ACE Inhibitors When combined with beta-blockers, ACE inhibitors can cause hypotension, particularly in the setting of acute myocardial infarction. The antihypertensive effects of clonidine may be antagonized by beta-blockers. Propranolol Hydrochloride Extended-Release Capsules, USP, should be administered cautiously to patients withdrawing from clonidine. Alpha Blockers Prazosin has been associated with prolongation of first dose hypotension in the presence of beta-blockers. Postural hypotension has been reported in patients taking both beta-blockers and terazosin or doxazosin. Reserpine Patients receiving catecholamine-depleting drugs, such as reserpine should be closely observed for excessive reduction of resting sympathetic nervous activity, which may result in hypotension, marked bradycardia, vertigo, syncopal attacks, or orthostatic hypotension. Inotropic Agents Patients on long-term therapy with propranolol may experience uncontrolled hypertension if administered epinephrine as a consequence of unopposed alpha-receptor stimulation. Epinephrine is therefore not indicated in the treatment of propranolol overdose (see OVERDOSAGE ). Isoproterenol and Dobutamine Propranolol is a competitive inhibitor of beta-receptor agonists, and its effects can be reversed by administration of such agents, e.g., dobutamine or isoproterenol. Also, propranolol may reduce sensitivity to dobutamine stress echocardiography in patients undergoing evaluation for myocardial ischemia. Non-Cardiovascular Drugs Nonsteroidal Anti-Inflammatory Drugs Nonsteroidal anti-inflammatory drugs (NSAIDs) have been reported to blunt the antihypertensive effect of beta-adrenoreceptor blocking agents. Administration of indomethacin with propranolol may reduce the efficacy of propranolol in reducing blood pressure and heart rate. Antidepressants The hypotensive effects of MAO inhibitors or tricyclic antidepressants may be exacerbated when administered with beta-blockers by interfering with the beta blocking activity of propranolol. Anesthetic Agents Methoxyflurane and trichloroethylene may depress myocardial contractility when administered with propranolol. Warfarin Propranolol when administered with warfarin increases the concentration of warfarin. Prothrombin time, therefore, should be monitored. Neuroleptic Drugs Hypotension and cardiac arrest have been reported with the concomitant use of propranolol and haloperidol. Thyroxine Thyroxine may result in a lower than expected T 3 concentration when used concomitantly with propranolol.