Propranolol + Hydrochlorothiazide: Inderide (Wyeth-Ayerst)
Propranolol is used most often for the treatment of high blood pressure, angina, and abnormal heart rhythms. It is also used to treat the symptoms of anxiety and to prevent migraine headaches.
Propranolol was the first beta-blocker available in the United States. Beta-blockers are drugs that interfere with nerve signals transmitted by the chemical norepinephrine. They reduce the force and speed of the heartbeat and prevent dilation of certain blood vessels. These actions reduce the work load on the heart, relieve the muscle tremors that often accompany anxiety, and reduce the blood pressure in the brain to prevent migraines.
Propranolol is available as tablets, long-acting capsules, and solution for injection.
The dosage of propranolol must be adjusted for the condition and each individual person. When used orally, common dosages range from 40 to 320 mg per day. Dosages in the lower end of the range are usually prescribed for anxiety or the prevention of migraines. Angina, hypertension, and irregular heart rhythms are generally treated with higher dosages.
Propranolol should not be used by anyone with a known allergy to it. It should also not be used by anyone with certain heart conditions such as congestive heart failure.
People with angina who abruptly stop propranolol may experience heart attacks or more severe angina. When discontinuing the drug, its dosage should be tapered off with the guidance of a physician.
In general, people with bronchial diseases such as bronchial asthma, chronic bronchitis, or emphysema should not use propranolol because the drug may cause severe difficulty in breathing.
Because propranolol affects the body's sugar metabolism, it should be used with caution in people with diabetes or hypoglycemia (low blood sugar). Propranolol may mask certain clinical signs of thyroid disease and interfere with thyroid-function tests. Similarly, propranolol may interfere with tests for glaucoma.
Because of the risk of side effects, propranolol should be used with caution in people with impaired kidney or liver function.
Lethargy and cold hands and feet are common side effects of propranolol. Less common side effects include irregular heartbeat or rhythm, heart failure, low blood pressure, light-headedness, insomnia, weakness, fatigue, mental depression, visual disturbances, hallucinations, nightmares/vivid dreams, disorientation, short-term memory loss, emotional swings, clouded senses, nausea, vomiting, stomach irritation, cramping, diarrhea, constipation, allergic reactions, difficulty breathing, bone-marrow toxicity, hair loss, dry eyes, and impotence.
Propranolol has not been formally studied in pregnant women. In animal studies, it caused spontaneous abortions when administered at ten times the maximum human dose. It is not known whether the drug causes birth defects in humans. Pregnant women are encouraged to discuss the benefits and potential risks of propranolol with their physician before deciding to use the drug.
HIV can be passed from a woman to her child through breast milk. In areas where nutritional alternatives are readily available, breast-feeding is discouraged for HIV-positive women. Propranolol passes into breast milk, but at normal doses, side effects in nursing babies are uncommon.
The oral forms of propranolol are used in children. The usual pediatric dosage range is 2 to 4 mg per kg of body weight per day, in two equally divided doses. Doses above 16 mg per kg per day should not be used in children.
No changes in dosage or administration are required for older adults.
Propranolol may intensify the effects of reserpine, potentially causing severe side effects. Haloperidol used in combination with propranolol may cause low blood pressure and heart attack.
Propranolol may increase blood levels of chlorpromazine, antipyrine, lidocaine, and theophylline. Chlorpromazine and cimetidine may increase propranolol blood levels. Phenytoin, phenobarbitone, indomethacin, and rifampin may reduce blood levels of propranolol.
Aluminum hydroxide antacids and alcohol interfere with the absorption of propranolol into the body.
To maintain the most consistent blood levels of propranolol, it should be taken the same time every day on an empty stomach.
Other beta-blockers include sotalol, timolol, carteolol, and penbutolol. For treatment or prevention of nausea and vomiting, a number of different types of drugs are available. Drugs used include metoclopramide, antihistamines (e.g., dimenhydrinate, meclizine, and promethazine), phenothiazines (e.g., prochlorperazine or thiethylperazine), and serotonin uptake inhibitors (e.g., granisetron or ondansetron). The different types of drugs differ significantly in their side effects, and the choice of therapy is often determined by the side effects for which an individual is at risk.