Medications and Drugs

GENERIC NAME: propranolol

BRAND NAMES: Inderal, Inderal LA

DRUG CLASS AND MECHANISM: Propranolol is a beta- adrenergic blocking agent. Propranolol blocks the action of the sympathetic nervous system, a portion of the involuntary nervous system. The sympathetic nervous system stimulates the pace of the heart beat. By blocking the action of these nerves, propranolol reduces the heart rate and is useful in treating abnormally rapid heart rhythms. Propranolol also reduces the force of heart muscle contraction and lowers blood pressure. By reducing the heart rate and the force of muscle contraction, propranolol reduces heart muscle oxygen demand. Since angina occurs when oxygen demand of the heart exceeds supply, propranolol is helpful in treating angina.

PRESCRIPTION: yes

GENERIC AVAILABLE: yes

PREPARATIONS: Tablets: 10 mg, 20 mg, 40 mg, 60 mg, 80 mg. Capsules (long-acting): 60 mg, 80 mg, 120 mg, 160 mg.

STORAGE: Tablets and capsules should be stored at room temperature in a tightly closed container.

PRESCRIBED FOR: Propranolol is prescribed for patients with high blood pressure (hypertension). It is also used to treat chest pain (angina pectoris) related to coronary artery disease. Propranolol is also useful in slowing and regulating certain types of abnormally rapid heart rates (tachycardias). Other uses for propranolol include the prevention of migraine headaches and the treatment of certain types of tremors (familial or hereditary essential tremors). Propranolol is commonly used in persons with thyrotoxicosis (high blood levels of thyroid hormone) to slow down rapid heart rate and tremor.

DOSING: Should be taken before meals or at bedtime.

DRUG INTERACTIONS: Propranolol can aggravate breathing difficulties in patients with asthma, chronic bronchitis, or emphysema. In patients with existing slow heart rates (bradycardias) and heart blocks (defects in the electrical conduction of the heart), propranolol can cause dangerously slow heart rates, and even shock. Propranolol reduces the force of heart muscle contraction and can aggravate symptoms of heart failure. Calcium channel blockers, digoxin (Lanoxin), and haloperidol (Haldol) can cause lowering of blood pressure and heart rate to dangerous levels when administered together with propranolol. In patients with coronary artery disease, abruptly stopping propranolol can suddenly worsen angina, and occasionally precipitate heart attacks. If it is necessary to discontinue propranolol, its dosage can be reduced gradually over several weeks. Propranolol can mask the early warning symptoms of low blood sugar (hypoglycemia), and should be used with caution in patients receiving treatment for diabetes. Safe use in children has not been established. It is not habit forming.

Many medicines interact with propranolol. Alcohol and aluminum containing antacids reduce the absorption of propranolol. Phenytoin (Dilantin), phenobarbital, and rifampin reduce the blood levels of propranolol. Cimetidine (Tagamet) and chlorpromazine increase the blood levels of propranolol. Propranolol increases the blood levels of certain medicines such as theophylline and lidocaine.

PREGNANCY: Safe use during pregnancy has not been established.

SIDE EFFECTS: Propranolol is generally well tolerated, and side effects are mild and transient. Rare side effects include abdominal cramps, diarrhea, constipation, fatigue, insomnia, nausea, depression, dreaming, memory loss, fever, impotence, lightheadedness, slow heart rate, low blood pressure, numbness, tingling, cold extremities, sore throat, and shortness of breath or wheezing.

Reference: FDA Prescribing Information

Last Editorial Review: 4/20/2001

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