A group of drugs used to treat heart failure and high blood pressure
Angiotensin converting enzyme (ACE) inhibitor drugs are commonly used in the treatment of chronic heart failure, in which the efficiency of the heart in pumping blood around the body is reduced. ACE inhibitors are also used to treat high blood pressure (see Hypertension), and may also be used to treat diabetic kidney disease. In this disorder, the small blood vessels in the filtering units of the kidneys are damaged and, as a result of this, protein leaks into the urine.
How do they work?
ACE inhibitors prevent the normal formation in the body of angiotensin II, a hormone that causes constriction (narrowing) of blood vessels. By reducing the amount of angiotensin II present in the blood, ACE inhibitors allow blood vessels to dilate (widen). This widening of blood vessels throughout the body reduces blood pressure, which makes it easier for the heart to pump blood and therefore alleviates heart failure.
The mechanism by which ACE inhibitor drugs are effective in relieving diabetic kidney disease is not entirely understood. ACE inhibitors are not given to people with certain other types of kidney damage because they may make the condition worse.
How are they used?
You will probably need to take these drugs for several months at least, and sometimes years. Before you are given an ACE inhibitor to treat heart failure or high blood pressure, you may have a blood test to check that your kidney function is normal. Your doctor is likely to prescribe a low oral dose of the drug initially. The dose is gradually increased over several weeks until an effective level is reached. You may be advised to take the first dose at bedtime because it may cause your blood pressure to fall rapidly, making you feel light-headed. If you are elderly or taking another drug for high blood pressure, such as a diuretic, your doctor may suggest that you try a small dose while still in the doctor’s surgery so that you can be monitored in case you have a sudden drop in blood pressure.
What are the side effects?
Light-headedness can occur if there is a temporary fall in blood pressure and not enough blood reaches the brain. If lightheadedness persists, you should consult your doctor. He or she may wish to adjust your dose. You should not drive or undertake hazardous tasks until you know how you are affected by the drug.
Other common side effects that ACE inhibitors may cause include a persistent dry cough, muscle cramps, diarrhoea, and occasionally the skin condition urticaria. A rare but serious side effect is kidney damage.
If you are taking an ACE inhibitor drug, do not take a nonsteroidal anti-inflammatory drug without first consulting your doctor because the combination may increase the risk of kidney damage.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
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