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Capoten was the first of a new class of blood pressure medicines called ACE (for angiotensin-converting enzyme) inhibitors. The development of this unique drug almost reads like a medical mystery. It all started with the venom of a poisonous Brazilian snake, the deadly jararaca, whose bite caused severe hemorrhaging. An extract from the venom was found to affect the kidney and ultimately blood pressure regulation. This led to the creation of enzyme blockers such as Capoten and Vasotec which are radically altering the treatment of hypertension and congestive heart failure.

Side Effects and Interactions

Capoten can cause a number of uncomfortable side effects.

Be alert for skin rash, itching, an annoying dry cough, fast or irregular heart beats, chest pain, nausea, diarrhea, vomiting, insomnia, fatigue, dizziness and headache. The skin may be more vulnerable to sunburn. An unusual adverse effect of Capoten may be loss of taste. Fortunately, this sense may return to normal after a few months.

Report any symptoms or suspected side effects without delay. People with kidney problems must be monitored extremely carefully, as Capoten can make kidney function worse. Even normal people should have kidneys checked periodically. A number of compounds can interact with Capoten, especially potassium and potassium-sparing diuretics. It is usually best to avoid potassium supplements, including low-sodium salt substitutes.

Diuretics such as Dyazide, Aldactazide and Moduretic which preserve potassium can also cause dangerous elevations in potassium. Other drugs that can interact with Capoten include aspirin and the arthritis medicine Indocin, the gout medicine Zyloprim, and the depression drug lithium. Check with your doctor and pharmacist to make sure Capoten is safe in combination with any other drugs you take.

Special Precautions

The very first dose of Capoten may cause dizziness, especially for older people. Be especially careful until your body adjusts.  When you first start taking Capoten, be alert for a rare but serious reaction. Some people have experienced swelling of the face, lips, tongue and throat which can make breathing difficult if not impossible. This requires immediate emergency treatment.

Another uncommon but dangerous reaction is a drop in infection-fighting white blood cells. If you develop chills, fever, sore throat and mouth sores contact your physician promptly. Blood tests are required to detect this problem. This risk is greater for patients with certain predisposing conditions such lupus, scleroderma or kidney problems.

Capoten should not be taken by pregnant women in their second or third trimester unless there is no alternative. It may damage the fetus.

Taking the Medicine

The manufacturer recommends that Capoten be taken one hour before meals. Food can interfere with the absorption of this medicine, reducing the amount that gets into the blood stream by up to 40 percent. Do not stop taking Capoten suddenly, as this could lead to complications. If you must discontinue the drug, your physician will instruct you in tapering off gradually.

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About the Author
Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.”.
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