Angiotensin-converting enzyme inhibitors


How you take a drug can affect how well it works and how safe it ill be for you. Sometimes it can be almost as important as what you take. Timing, what you eat and when you eat, proper dose, and many other factors can mean the difference between feeling better, staying the same, or feeling worse. This drug information page is intended to help you make your treatment work as effectively as possible. It is important to note, however, that this is only a guideline. You should talk to your doctor about how and when to take any prescribed drugs.

The 10th installment of this series features a class of drugs called angiotensin-converting enzyme inhibitors.
Conditions These Drugs Treat

All angiotensin-converting enzyme (ACE) inhibitors are used to treat high blood pressure. In addition, captopril and enalapril are used to treat heart failure, usually only after other medications, such as digitalis, have been tried. ACE inhibitors can be used for other conditions as determined by your doctor.
How to Take

Captopril should be taken on an empty stomach one hour before meals. All other ACE inhibitors can be taken without regard to meals.

ACE inhibitors are potent medicines that treat but do not cure chronic conditions such as high blood pressure. That is why it is important to take the ACE inhibitor regularly and make sure you're taking the right amount. Taking doses at the same time each day will help you remember to take the drag regularly. Continue any diet and exercise program prescribed by your doctor.
Missed Doses

If you miss a dose, take it as soon as you remember. As a rough guideline, estimate the number of hours between when you should have taken your missed dose and when your next dose is scheduled (if you take it twice a day, for instance, the time between doses is 12 hours). If you have passed the halfway point (which is six hours in this example), do not take the missed dose. Instead, continue with your next regularly scheduled dose. Do not take two doses at the same time.
Relief of Symptoms

ACE inhibitors begin to work immediately after the first dose. However, a few weeks may be needed before the full effects occur. The dosage of the ACE inhibitor may need to be adjusted by your doctor when you first begin taking it.
Side Effects and Risks

Fatigue, dizziness, headache, insomnia, nausea, vomiting, and diarrhea are all common side effects. These are all usually mild.

Loss of the taste sense can occur, especially with captopril. Taste usually returns within two to three months, even if you are still on the medication. Sometimes slight weight loss can accompany the loss of taste.

Some people develop a persistent dry cough while taking ACE inhibitors. The cough usually does not go away unless the medication is stopped. If this side effect occurs and is bothersome, you should discuss it with your doctor.

ACE inhibitors can cause dizziness, lightheadedness, or even fainting, usually during the first few days. These effects are due to lowered blood pressure and occur mostly when getting up from a sitting or prone position. Consult your doctor if these symptoms persist, especially if fainting occurs. Sometimes changes in the dosage of the ACE inhibitor or other medications can ease these symptoms.

A mild, sometimes itchy, skin rash can occur and may be accompanied by fever or joint pains. This usually happens within the first four weeks of beginning an ACE inhibitor, especially captopril. Consult your doctor if this occurs since dosage changes or other medications can help clear the rash.

More serious but infrequent reactions that sometimes occur with ACE inhibitors are:

* Fever and chills. Although rare, ACE inhibitors (mostly captopril) can cause a decrease in certain white blood cells, increasing susceptibility to infections. Common symptoms include fever, chills, sore throat, and mouth sores. If these symptoms occur, contact your doctor immediately. The lowered cell count is usually reversible.
* Allergic reaction. This is evidenced by sudden difficulty in swallowing or breathing; hoarseness; flushed or pale complexion; and swelling of the face, mouth, hands, or feet. Stop taking the medication immediately, and call your doctor or seek emergency help if the symptoms are severe.
* Chest (heart-related) pain, rapid or pounding heartbeat. These symptoms tend to occur most often when you first start taking an ACE inhibitor.

If these serious reactions or other new symptoms occur, contact your doctor immediately.
Precautions and Warnings

Do not stop taking an ACE inhibitor on your own.

ACE inhibitors can sometimes cause a reversible decrease in kidney function. Your doctor may periodically check your kidney function by either blood or urine tests while you are on the medication. If you notice your feet or ankles swelling or weight gain, notify your doctor.

Exercising in hot weather, excessive perspiration, vomiting, or diarrhea can lead to loss of fluid (dehydration) and intensify the ability of ACE inhibitors to lower blood pressure. Low blood pressure could lead to severe dizziness or even fainting. Consult your physician if any of these conditions occurs.

ACE inhibitors can occasionally cause the body to retain too much potassium. Rarely, potassium excess in the body can cause confusion, irregular heartbeat, weakness in the legs, nervousness, or tingling in the hands, feet or lips. If any of these occurs, contact your doctor immediately. Also, consult your doctor before using any salt substitutes, since many of these contain potassium.

Diabetic patients who test their urine for acetone should be aware that captopril can cause a false-positive reading.

Animal studies show ACE inhibitors may cause problems during pregnancy. In a few human reports, some babies of mothers taking ACE inhibitors have been born with very low blood pressure. Let your doctor know if you are or intend to become pregnant while on an ACE inhibitor.

Captopril is secreted into breast milk. It is not known if either enalapril or lisinopril gets into breast milk. In general, breast-feeding is not recommended while taking these drugs unless directed by a doctor.

Common Names

captopril (Capoten)

enalapril (Vasotec)

lisinopril (Prinivil, Zestril)

ramipril (Altace)



By Igor Cerny

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