ACE Inhibitors

Individuals who suffer from hypertension are often prescribed medication by a healthcare professional to help manage their condition. Medications that lower blood pressure are called antihypertensives and come in a variety of classes. ACE inhibitors are one class of antihypertensives.

“ACE” stands for “angiotensin-converting enzyme.” These medications lower blood pressure by encouraging blood vessels to relax and open, which promotes the free flow of blood. In addition to treating high blood pressure, ACE inhibitors treat congestive heart failure.

Since 1981, ACE inhibitors commonly have been prescribed to treat high blood pressure because they tend to be well-tolerated by patients. They’re usually taken just once a day, often in the morning. They may be prescribed along with diuretics or calcium channel blockers, which also are used to treat high blood pressure.

How They Work

ACE inhibitors work in two ways. First, they decrease sodium retention in the kidneys. Secondly, they de-activate an enzyme that usually converts angiotensin I (which is inactive) to angiotensin II (which is active). Normally, angiotensin II raises blood pressure by constricting arteries and promoting the retention of sodium and water. In more basic terms, your blood vessels are more relaxed when the hormone that usually causes them to constrict isn’t produced. This means that blood flowing through the vessels has more space to move and isn't under as much pressure.

For a better visual, imagine a garden hose. It would take longer or require more pressure to pour a gallon of water through a hose with a quarter inch diameter than it would to pour it through a garden hose with a one inch diameter. Less pressure would cause the water to dribble out of the hose. More pressure would cause the water to spray out.


ACE inhibitors can also have a positive impact on your health—and not just your blood pressure. They can slow the progression of atherosclerosis (hardening of the arteries) and have been proven beneficial for those with diabetes, slowing the progression of kidney disease and damage. Diabetes patients should discuss this potential benefit with their physicians.

Side Effects and Risks

Although most people tolerate these medications well, they can cause a number of side effects. These include:

  • fatigue
  • rash
  • decreased ability to taste
  • a dry, hacking cough
  • low blood pressure
  • fainting

Rarely, ACE inhibitors can cause swelling of the lips, tongue, and throat, which can make it difficult to breathe. This is more likely to happen in African-Americans and smokers. Finally, people with impaired kidney function should use caution when taking this type of medication, due to its ability to raise potassium levels. Because ACE inhibitors can cause low blood pressure, kidney failure, high potassium levels, fetal abnormalities and death in infants, they’re not recommended for pregnant women. Common ACE inhibitors include:

  • benazepril (Lotensin)
  • captopril (Capoten)
  • enalapril (Vasotec)
  • fosinopril (Monopril)
  • lisinopril (Prinivil, Zestril)
  • quinapril (Accupril)
  • ramipril (Altace)

Because some over-the-counter pain medications may decrease the effectiveness of ACE inhibitors, you should check with your physician before taking medications such as ibuprofen (Advil, Motrin), naproxen (Aleve), and other nonsteroidal anti-inflammatory drugs (NSAIDS). Taking these medications occasionally or by accident while taking a prescribed ACE inhibitor probably isn’t harmful, but you should avoid using them regularly. Your doctor and pharmacist should each have a complete list of the medications you’re taking.

Taking Your Medication

As with any medication, the fact that an ACE inhibitor is working doesn’t mean you should stop taking it. Although it's tempting to toss your pills once you're feeling better, taking them consistently will help keep your blood pressure in a healthy range. If you're experiencing side effects, call your doctor before you discontinue the medication. Your side effects may diminish over time or your doctor may have special instructions for stopping taking the medication.

ACE inhibitors can be an important tool in maintaining low blood pressure and a healthy heart. They can help prevent damage to your heart, keep your heart working following a heart attack, reduce symptoms of heart disease, and help you live a longer, healthier life.