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ACE INHIBITORS - a patient's guide


ACE Inhibitors are used to treat high blood pressure, heart conditions and kidney problems. This article profiles their use and side effects.

Brand names:

  • Benazepril - Cibacen
  • Captopril - Capoten
  • Cilazapril - Inhibace
  • Enalapril - Renitec
  • Lisinopril - Prinivil, Zestril
  • Perindopril - Coversyl
  • Quinapril - Accupril
  • Trandolapril - Gopten, Odrik

Use: High blood pressure and heart failure

These type of medicines are known as Angiotensin Converting Enzyme (ACE) Inhibitors, and are used primarily for the treatment of hypertension (high blood pressure) and congestive heart failure. They can also be used for diabetic nephropathy (kidney problems) and after a heart attack if the heart muscle is not working very well.

ACE-Inhibitors work by suppressing the angiotensin-aldosterone system (via ACE) which prevents the formation of angiotensin II (powerful vasoconstrictor). This plays a major role in the regulation of blood pressure and reducing pre/after load on the heart which improves the ability to pump blood around the body for the patient.


  • Patients on diuretics (start on lower dose)
  • Previous allergy to ACE inhibitors
  • Pregnancy or breastfeeding
  • Immunosuppressant therapy (low white blood cell count)
  • Severe congestive heart failure
  • Surgery and general anesthesia
  • Liver impairment
  • Angioedema, kidney problems, aortic stenosis

Side effects:

ACE Inhibitors can cause low blood pressure (increase dosages slowly and have regular checks), kidney impairment (regular blood tests of kidney function are required), skin rash, persistent dry cough, upper respiratory problems, stomach upset, skin rash, photosensitivity, headache, dizziness, fatigue, taste disturbances etc.

It is always best to discuss any perceived side effects with your doctor as various other conditions may cause very similar symptoms.

It is important to have regular blood pressure checks and blood tests of kidney function. More regular, and closer checking and testing may be needed if you are unwell from another condition.

Elderly patients are more prone to side effects and this is especially so during another illness e.g. pneumonia with dehydration or diarrhoea.

Rare side effects include: nephrotic syndrome, chest pain, neutropenia, blood disorders, liver impairment.


There is a risk of hyperkalaemia (high potassium levels) with K+-sparing diuretics (e.g. aldactone), cyclosporin and potassium salts.

An enhanced hypotensive (low blood pressure) effect with alcohol, anaesthetics, antipsychotics, antidepressants, vasodilators, antihypertensives, muscle relaxants, diuretics, hypnotics etc.

Other interactions involve tetracycline antibiotics, NSAIDs (Nonsteroidal anti-inflammatories), antidiabetics, antacids, corticosteroids, lithium and oral contraceptives (the pill).

Patient information:

  • Follow the instructions carefully on the label of this medicine or as directed by your doctor.
  • Take this medicine regularly to control high blood pressure and help improve heart failure.
  • When starting therapy, get up slowly out of bed or standing up if you feel dizzy or light-headed. Discuss symptoms like this with your doctor - the dose may need to be reduced.
  • Food: Take with food if it upsets your stomach and with a glass of water.
  • Alcohol: Avoid excess intake since this can enhance hypotensive effect (dizziness).
  • Missed dose: Take as soon as you remember (do not double dose).
  • Tell your pharmacist that you suffer from heart/blood pressure problems when purchasing over-the-counter (OTC) medicines.
  • Drink plenty or water during exercise and hot weather and take care when driving/ operating machinery (due to dizziness or light-headedness in some people).
  • Monitor your blood pressure regularly to make sure this medicine is working (discuss with doctor).
  • Contact your doctor or seek medical attention if side effects are severe (chest pain, shortness of breath, skin rash or muscle pain) or ongoing (vomiting or diarrhoea).
  • It is best to seek prompt medical advice if you have another illness as well as this can cause side effects in a previously stable patient.

See also:

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