Inderal

Brand Name and Generic

Inderal is the brand name for the generic drug propranolol hydrochloride. It is classified as a beta-adrenergic blocking agent, more commonly known as a beta blocker.

Available Dosage Forms

Inderal is available in various forms, including immediate-release tablets, long-acting capsules (Inderal LA), and an oral solution.

Therapeutic Indications

Inderal is indicated for the management of hypertension, angina pectoris, and ventricular and supraventricular tachyarrhythmias. It is also used in the treatment of hypertrophic subaortic stenosis, pheochromocytoma (with an alpha blocker), and as a prophylactic for migraine headaches. It also finds use in the management of situational and generalized anxiety.

Mechanism of Action

Inderal nonspecifically blocks beta-1 and beta-2 adrenergic receptors, decreasing heart rate and myocardial contractility, reducing cardiac output, and suppressing renin release, hence lowering blood pressure. It also stabilizes the neuronal membrane by blocking sodium channels in the brain, which is believed to be effective in preventing migraine headaches.

Pharmacokinetics

After oral administration, propranolol is rapidly absorbed, with peak plasma concentrations occurring about 1-4 hours post-dose. It is extensively distributed throughout the body and highly bound to plasma proteins. Metabolism occurs predominantly in the liver, and less than 1% is excreted unchanged in urine.

Recommended Dosages

The dosage of Inderal varies depending on the condition being treated. For hypertension, the initial dosage may be 80 mg per day in divided doses, increasing at weekly intervals according to response. In migraine prophylaxis, the initial dose is typically 80 mg per day in divided doses, gradually increasing as required.

Administration Guidelines

Inderal should be taken before meals and at bedtime when prescribed in divided doses. The extended-release formulation (Inderal LA) should be taken once a day at the same time each day, usually in the morning, and should not be chewed or crushed.

Drug Interactions

Inderal can interact with a range of drugs, including other blood pressure medications, antiarrhythmic drugs, and certain antidepressants. It may also interact with CYP2D6 inhibitors, such as some SSRIs, and CYP1A2 inhibitors like cimetidine, possibly increasing propranolol levels in the blood.

Side Effects and Adverse Reactions

Common side effects of Inderal include bradycardia, fatigue, dizziness, and gastrointestinal discomfort. More severe reactions may involve hypotension, bronchospasm in asthma patients, and heart failure exacerbation.

Monitoring Parameters

Patient’s heart rate, blood pressure, and clinical symptoms should be closely monitored. Liver function tests and renal function should also be periodically assessed, especially in long-term use.

Special Populations Considerations

Dosage adjustments may be necessary for elderly patients, those with hepatic or renal impairment, and for patients who are smokers due to altered pharmacokinetics in these populations.

Pregnancy and Lactation

Inderal falls under Pregnancy Category C, meaning risk cannot be ruled out. It should only be used if the potential benefit justifies the potential risk to the fetus. Propranolol is excreted in breast milk, so caution is advised when it is administered to a nursing mother.

Overdosage Management

In cases of overdose, symptomatic and supportive treatment should be initiated promptly. Measures may include induction of emesis or gastric lavage, and administration of activated charcoal. Atropine and vasopressors may also be used to improve myocardial contractility and heart rate.

Patient Instructions

Patients should be instructed to take Inderal exactly as prescribed, to not discontinue medication abruptly, and to report any unusual symptoms to their healthcare provider immediately.

Storage and Handling

Inderal should be stored at room temperature, away from light and moisture. Keep the medication out of reach of children.

Disposal of Unused Medication

Unused or expired Inderal should be disposed of properly, preferably through a take-back program. If not available, the medication should be mixed with an unpalatable substance and discarded in the household trash in a sealed container.