Angiotensin-converting Enzyme (ACE) Inhibitors


ACE inhibitors belong to the class of medicines called high blood pressure medicines (antihypertensives). They are used to treat high blood pressure (hypertension).

High blood pressure adds to the workload of the heart and arteries. If it continues for a long time, the heart and arteries may not function properly. This can damage the blood vessels of the brain, heart, and kidneys, resulting in a stroke, heart failure, or kidney failure. High blood pressure may also increase the risk of heart attacks. These problems may be less likely to occur if blood pressure is controlled.

Lisinopril, captopril, ramipril, and trandolapril are used in some patients after a heart attack. After a heart attack, some of the heart muscle is damaged and weakened. The heart muscle may continue to weaken as time goes by. This makes it more difficult for the heart to pump blood. Lisinopril use may be started within 24 hours after a heart attack to increase survival rate. Captopril, ramipril, and trandolapril help slow down the further weakening of the heart.

Captopril is also used to treat kidney problems in some diabetic patients who use insulin to control their diabetes. Over time, these kidney problems may get worse. Captopril may help slow down the further worsening of kidney problems.

In addition, some ACE inhibitors are used to treat congestive heart failure or may be used for other conditions as determined by your doctor.

The exact way that these medicines work is not known. They block an enzyme in the body that is necessary to produce a substance that causes blood vessels to tighten. As a result, they relax blood vessels. This lowers blood pressure and increases the supply of blood and oxygen to the heart.

These medicines are available only with your doctor’s prescription, in the following dosage forms:

  • Oral Benazepril       o Tablets (U.S. and Canada)  
  • Captopril       o Tablets (U.S. and Canada)  
  • Cilazapril       o Tablets (Canada)  
  • Enalapril       o Tablets (U.S. and Canada)  
  • Fosinopril       o Tablets (U.S. and Canada)  
  • Lisinopril       o Tablets (U.S. and Canada)  
  • Moexipril       o Tablets (U.S.)  
  • Perindopril       o Tablets (U.S. and Canada)  
  • Quinapril       o Tablets (U.S. and Canada)  
  • Ramipril       o Capsules (U.S. and Canada)  
  • Trandolapril       o Tablets (U.S. and Canada)  
  • Parenteral Enalaprilat       o Injection (U.S. and Canada)

Before Using This Medicine

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For the angiotensin-converting enzyme (ACE) inhibitors, the following should be considered:

Allergies- Tell your doctor if you have ever had any unusual or allergic reaction to benazepril, captopril, cilazapril, enalapril, fosinopril, lisinopril, moexipril, perindopril, quinapril, ramipril, or trandolapril. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy- Use of ACE inhibitors during pregnancy, especially in the second and third trimesters (after the first three months) can cause low blood pressure, severe kidney failure, too much potassium, or even death in the newborn. Therefore, it is important that you check with your doctor immediately if you think that you may be pregnant. Be sure that you have discussed this with your doctor before taking this medicine. In addition, if you are taking:

  • Benazepril- Benazepril has not been shown to cause birth defects in animals when given in doses more than 3 times the highest recommended human dose.  
  • Captopril- Studies in rabbits and rats at doses up to 400 times the recommended human dose have shown that captopril causes an increase in deaths of the fetus and newborn. Also, captopril has caused deformed skulls in the offspring of rabbits given doses 2 to 70 times the recommended human dose.  
  • Enalapril- Studies in rats at doses many times the recommended human dose have shown that use of enalapril causes the fetus to be smaller than normal. Studies in rabbits have shown that enalapril causes an increase in fetal death. Enalapril has not been shown to cause birth defects in rats or rabbits.  
  • Fosinopril- Studies in rats have shown that fosinopril causes the fetus to be smaller than normal. Studies in rabbits have shown that fosinopril causes fetal death, probably due to extremely low blood pressure. In rats, birth defects such as skeletal and facial deformities were seen. However, it is not clear that the deformities were related to fosinopril. Birth defects were not seen in rabbits.  
  • Lisinopril- Studies in mice and rats at doses many times the recommended human dose have shown that use of lisinopril causes a decrease in successful pregnancies, a decrease in the weight of infants, and an increase in infant deaths. It has also caused a decrease in successful pregnancies and abnormal bone growth in rabbits. Lisinopril has not been shown to cause birth defects in mice, rats, or rabbits.  
  • Moexipril- Studies in rats given up to 90 times the recommended human dose, and studies in rabbits given up to 0.7 times the recommended human dose, did not show that moexipril causes birth defects in animals.  
  • Perindopril- Studies in rabbits given up to 50 times the recommended human dose, and monkeys given up to 17 times the recommended human dose, did not show that perindopril causes birth defects in animals.  
  • Quinapril- Studies in rats have shown that quinapril causes lower birth weights and changes in kidney structure of the fetus. However, birth defects were not seen in rabbits given quinapril.  
  • Trandolapril- Studies in rabbits, rats, and monkeys did not show that trandolapril causes any birth defects in animals.


  • Benazepril, captopril, enalapril enalaprilat, and fosinopril-These medicines pass into breast milk.  
  • Cilazapril, lisinopril, moexipril, perindopril, quinapril, ramipril, and trandolapril-It is not known whether these medicines pass into breast milk. However, these medicines have not been reported to cause problems in nursing babies.

Children- Children may be especially sensitive to the blood pressure-lowering effect of ACE inhibitors. This may increase the chance of side effects or other problems during treatment. Therefore, it is especially important that you discuss with the child’s doctor the good that this medicine may do as well as the risks of using it.

Older adults- This medicine has been tested in a limited number of patients 65 years of age or older and has not been shown to cause different side effects or problems in older people than it does in younger adults.

Other medicines- Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking or receiving ACE inhibitors it is especially important that your health care professional know if you are taking any of the following:

  • Alcohol or  
  • Diuretics (water pills)-Effects on blood pressure may be increased. In addition, some diuretics make the increase in potassium in the blood caused by ACE inhibitors even greater  
  • Potassium-containing medicines or supplements or  
  • Salt substitutes or  
  • Low-salt milk-Use of these substances with ACE inhibitors may result in an unusually high potassium level in the blood, which can lead to heart rhythm and other problems

Other medical problems- The presence of other medical problems may affect the use of the ACE inhibitors. Make sure you tell your doctor if you have any other medical problems, especially:

  • Diabetes mellitus (sugar diabetes)-Increased risk of potassium levels in the body becoming too high, or increased effect of insulin on control of blood sugar  
  • Heart or blood vessel disease or  
  • Low sodium diet-Lowering blood pressure may make problems resulting from these conditions worse  
  • kidney disease or  
  • Liver disease- ACE inhibitors’ effects may be increased because of slower removal of medicine from the body  
  • Kidney transplant- Increased risk of kidney disease caused by ACE inhibitors  
  • Systemic lupus erythematosus (SLE)- Increased risk of blood problems caused by ACE inhibitors  
  • Previous reaction to any ACE inhibitor or previous occurrence involving hoarseness; swelling of face, mouth, hands, or feet; or sudden trouble in breathing-Reaction is more likely to occur again

Proper Use of This Medicine

To help you remember to take your medicine, try to get into the habit of taking it at the same time each day.

For patients taking captopril or moexipril :

  • These medicines are best taken on an empty stomach 1 hour before meals, unless you are otherwise directed by your doctor.

For patients taking ramiprilcapsules: If you have trouble swallowing capsules, you may open the ramipril capsule and mix the medicine with applesauce, water or apple juice. Mix only one dose at a time just before taking it. You may mix a dose ahead of time and save it for no more than 24 hours at room temperature or 18 hours in the refrigerator. If you are unsure about these instructions, ask your doctor or pharmacist.

For patients taking this medicine for high blood pressure :

  • In addition to the use of the medicine your doctor has prescribed, treatment for your high blood pressure may include weight control and care in the types of foods you eat, especially foods high in sodium. Your doctor will tell you which of these are most important for you. You should check with your doctor before changing your diet.  
  • Many patients who have high blood pressure will not notice any signs of the problem. In fact, many may feel normal. It is very important that you take your medicine exactly as directed and that you keep your appointments with your doctor even if you feel well.  
  • Remember that this medicine will not cure your high blood pressure but it does help control it. Therefore, you must continue to take it as directed if you expect to lower your blood pressure and keep it down. You may have to take high blood pressure medicine for the rest of your life . If high blood pressure is not treated, it can cause serious problems such as heart failure, blood vessel disease, stroke, or kidney disease.

Missed dose-
If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

To store this medicine:

  • Keep out of the reach of children.  
  • Store away from heat and direct light.  
  • Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.  
  • Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

Precautions While Using This Medicine

It is important that your doctor check your progress at regular visits to make sure that this medicine is working properly and to check for unwanted effects.

For patients taking this medicine for high blood pressure :

  • Do not take other medicines unless they have been discussed with your doctor. This especially includes over-the-counter (nonprescription) medicines for appetite control, asthma, colds, cough, hay fever, or sinus problems, since they may tend to increase your blood pressure.

Dizziness or light-headedness may occur after the first dose of this medicine, especially if you have been taking a diuretic (water pill). Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are dizzy.

Check with your doctor right away if you become sick while taking this medicine, especially with severe or continuing nausea and vomiting or diarrhea. These conditions may cause you to lose too much water and lead to low blood pressure.

Notify your doctor immediately if you are or become pregnant while taking this medicine.

Check with your doctor if you have any signs of infection such as chills, fever, or sore throat, because these may be signs of neutropenia.

Check with your doctor right away if you have symptoms of jaundice (yellow skin or eyes) because these may be signs of a serious liver condition.

Dizziness, light-headedness, or fainting also may occur if you exercise or if the weather is hot. Heavy sweating can cause loss of too much water and low blood pressure. Use extra care during exercise or hot weather.

Avoid alcoholic beverages until you have discussed their use with your doctor. Alcohol may make the low blood pressure effect worse and/or increase the possibility of dizziness or fainting.

Check with your doctor if you experience any welts or swelling around your face, throat or tongue. Swelling in the mouth or throat area may cause breathing to become very difficult and could result in death.

Check with your doctor if you have strong stomach pain. This could be a symptom of a condition called intestinal angioedema. Your doctor may have to use a CT scan or an ultrasound to diagnose this condition.

Before having any kind of surgery (including dental surgery) or emergency treatment, tell the medical doctor or dentist in charge that you are taking this medicine.

For patients taking captopril or fosinopril:

  • Before you have any medical tests, tell the doctor in charge that you are taking this medicine. The results of some tests may be affected by this medicine.

Side Effects of This Medicine

  • Side Effects of This Medicine     Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.     Check with your doctor immediately if any of the following side effects occur:       o Rare           + Fever and chills;  hoarseness;  swelling of face, mouth, hands, or feet;  trouble in swallowing or breathing (sudden);  stomach pain, itching of skin, or yellow eyes or skin     Check with your doctor as soon as possible if any of the following side effects occur:       o Less common           + Dizziness, light-headedness, or fainting;  skin rash, with or without itching, fever, or joint pain       o Rare           + Abdominal pain, abdominal distention, fever, nausea, or vomiting ;  chest pain       o Signs and symptoms of too much potassium in the body           + Confusion;  irregular heartbeat;  nervousness;  numbness or tingling in hands, feet, or lips;  shortness of breath or difficulty breathing;  weakness or heaviness of legs

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

  • More common       o Cough (dry, persistent);  headache  
  • Less common       o Diarrhea;  loss of taste;  nausea;  unusual tiredness

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.

Additional Information

Once a medicine has been approved for marketing for a certain use, experience may show that it is also useful for other medical problems. Although these uses are not included in product labeling, ACE inhibitors are used in certain patients with the following medical conditions:

  • Hypertension in scleroderma (high blood pressure in patients with hardening and thickening of the skin)  
  • Renal crisis in scleroderma (kidney problems in patients with hardening and thickening of the skin)

Other than the above information, there is no additional information relating to proper use, precautions, or side effects for these uses.

Brand Names

Some commonly used brand names are:

In the U.S.-

  • Accupril  
  • Aceon  
  • Altace  
  • Capoten  
  • Lotensin  
  • Mavik  
  • Monopril  
  • Prinivil  
  • Univasc  
  • Vasotec  
  • Zestril

Johns Hopkins patient information

Copyright 1996-2014 Cerner Multum, Inc. Version: 16.02.
Revision date: June 20, 2011
Last revised: by Tatiana Kuznetsova, D.M.D.

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