What are Angiotensin-converting enzyme inhibitors? How do they work?

Angiotensin-converting enzyme (ACE) inhibitors are a class of drugs that are used in the treatment and management of high blood pressure and heart failure. These drugs are vasodilators, they act by decreasing heart rate and systemic vascular resistance by blocking production of angiotensin II (a substance that narrows blood vessels) and improving blood flow.

Mechanism of action of ACE inhibitors

The drugs of this group are also used in combination with diuretics which will affect the renin-angiotensin system.

ACE inhibitors list

Examples of available ACE inhibitors include:

- Enalapril (Vasotec)

- Captopril (Capoten)

- Lisinopril (Prinivil, Zestril)

- Fosinopril (Monopril)

- Benazepril (Lotensin)

- Moexipril (Univasc)

- Perondopril (Aceon)

- Quinapril (Accupril)

- Ramipril (Altace)

- Trandolapril (Mavik)

*Note that all the generic names of ACE inhibitors end in the suffix “pril’”.

ACE inhibitors uses

Angiotensin-converting enzyme inhibitors such as Lisinopril and Enalapril are recommended as first line therapy for treatment of hypertension particularly in -patients with high coronary disease risk or history of diabetes.

ACE inhibitors are also prescribed to treat or improve symptoms of other conditions including:

- Left ventricular dysfunction

- Myocardial infraction

- Heart failure

- Diabetes

- Chronic kidney diseases

ACE inhibitors can also be used in combination with other drugs such as diuretics, depending on the severity of the condition.

All angiotensin-converting enzyme inhibitors are effective in the treatment of hypertension at equivalent doses.

Side effects of ACE inhibitors

The most common side effect of these drugs is cough, this side effect occurs with all angiotensin-converting enzyme inhibitors.

Other side effects of ACE inhibitors include:

- Headache

- Hypotension (low blood pressure)

- Hyperkalemia (High potassium level in the blood)

- Rash

- Fatigue

- Angioedema of face and limbs

- Fever

- Loss of taste

- Hepatotoxicity

Serum creatinine levels must be monitored, especially in patients who are suffering from renal diseases.

Monitoring potassium levels is also important especially in patients using potassium supplements, potassium-sparing diuretics, or aldosterone antagonists because of risk of hyperkalemia.

Who can't use ACE inhibitors?

ACE inhibitors should be used with caution in patients with impaired renal function or autoimmune disease.

Any person who is allergic to these drugs should not use them.

Pregnancy and breastfeeding

Angiotensin-converting enzyme inhibitors are teratogenic agents that leads to fetal morbidity and mortality; hence, they should not be used in during pregnancy especially in the second and third trimesters.

Some ACE inhibitors have been shown to pass into breast milk and may affect the baby, so they should be avoided.