Angiotensin-converting enzyme (ACE) inhibitors help relax blood vessels. ACE inhibitors prevent an enzyme in your body from producing angiotensin II, a substance in your body that affects your cardiovascular system in numerous ways, including narrowing your blood vessels. This narrowing can cause high blood pressure and force your heart to work harder.

Numerous ACE inhibitors are available. Which one is best for you depends on your health and the condition being treated.

Examples of ACE inhibitors include:

• Benazepril (Lotensin)
• Enalapril (Vasotec)
• Lisinopril (Prinivil, Zestril)

Doctors prescribe ACE inhibitors to prevent, treat or improve symptoms in a variety of conditions, such as:

• High blood pressure
• Coronary artery disease
• Heart failure
• Diabetes
• Certain chronic kidney diseases
• Heart attacks
• Scleroderma
• Migraines

Side effects include dry cough, increased blood-potassium level, rash, dizziness, lightheadedness, changes in taste and reduced appetite over long intervals. In rare cases — but more commonly in blacks and in smokers — ACE inhibitors can cause localized areas of your tissues to swell (angioedema). If it occurs in the throat, that swelling can be life-threatening.

Because ACE inhibitors can cause birth defects, don't take them if you are pregnant or plan to become pregnant.