Meds and you

Updated 11 February 2013


Fosinopril is an angiotensin-converting enzyme (ACE) inhibitor prescribed for the treatment of high blood pressure.


Fosinopril is the active ingredient of Merck-Fosinopril and Monopril.

Fosinopril is also one of multiple active ingredients found in Monozide (Fosinopril + Hydrochlorothiazide).

General Information

Fosinopril is an angiotensin-converting enzyme (ACE) inhibitor prescribed for the treatment of high blood pressure. It causes blood vessels to relax and widen, thereby reducing high blood pressure.

This medication is not a cure for high blood pressure, but is effective in keeping it under control. For it to be effective you must take it regularly. High blood pressure declines slowly and it may take a few weeks for fosinopril to reach it full effect. Keep taking this medicine during this period, even if you are feeling better or fail to notice any improvement.

Fosinopril can be used on its own or in combination with certain other medication for high blood pressure. It is often effectively combined with diuretics. In black patients fosinopril is significantly less effective if not prescribed together with a diuretic.

The first couple of doses of this medication may cause a sudden drop in blood pressure which may cause dizziness or blackouts when you suddenly get up. It is therefore advised that you should be resting when starting treatment and lie down for 2 hours afterwards.

The use of fosinopril is often associated with a dry and persistent cough. Should you notice an irritating cough while being treated with this drug, it is advised that you contact you doctor.

Fosinopril should be avoided during pregnancy, especially the second and third trimester. Speak to your doctor about the use of this drug if you are planning to get pregnant, as it may cause harm to the unborn baby.

How does fosinopril work?

Fosinopril works by preventing the conversion of angiotensin I, a chemical in your blood, to a more powerful version, angiotensin II. Angiotensin II has a narrowing effect on blood vessels, thereby increasing blood pressure. Angiotensin II furthermore stimulates the production aldosterone, a hormone which promotes salt (sodium) retention in the body, an action which increases blood pressure.

By inhibiting the forming of angiotensin II fosinopril lowers blood pressure and thereby decreases the workload of the heart.

Fast facts

Drug schedule: Schedule 3

Available as: Fosinopril is available as tablets

What does it do? Lowers blood pressure

Overdose risk: Medium

Dependence risk: Low

Is fosinopril available as a generic? Yes

Is fosinopril available on prescription only? Yes

User information

Dietary advice: Fosinopril can be taken with or without food. It is advised to follow a low potassium diet - These include foods such as tomatoes and bananas.

Stopping this medicine: Use fosinopril as prescribed by your doctor, and do not discontinue treatment before speaking to him/her. Suddenly discontinuing the drug may case you blood pressure to increase dangerously. Dosage should be deceased gradually as directed by your doctor.

Prolonged use: No problems are expected. Your doctor may periodically test blood and urine, should the need arise.

Special precautions

Consult your doctor before using this drug if:

  • You have a kidney disease
  • You have a heart condition which your doctor is not aware of
  • You are allergic to ACE-inhibitor drugs
  • You are taking other medication
  • You are pregnant or planning to become pregnant.

Pregnancy: Avoid. Potential risk to the foetus has been reported. Consult your doctor before use, or if you are planning to fall pregnant.

Breastfeeding: Avoid. This medication is passed through breast milk and may affect your baby adversely. Consult your doctor before use.

Porphyria: Avoid. This medication may cause serious adverse effects. Consult your doctor before use.

Infants and children: This medication is not intended for use in children.

Elderly: Dosage may need to be adjusted according to kidney function and other medical conditions.

Driving and hazardous work: Caution is advised as use of this medication may lead to dizziness, light-headedness and/or sedation. Avoid such activities until you know how this medication affects you.

Alcohol: Avoid concomitant use of alcohol with this medication, as it may increase the possibility of dizziness.

Possible side effects

Side effect


Consult your doctor



Only if severe

In all cases







Dry cough









Loss of appetite






Muscle cramps



Swelling of face, lips, tongue or throat



Swelling of arms and legs



Difficulty swallowing



Abdominal pain with/without nausea/vomiting




Drug interactions


Possible allergic reactions


Enhanced blood pressure-lowering effect

Other medication for high blood pressure

Enhanced blood pressure-lowering effect


Increased risk of potassium toxicity


Effect on blood pressure is enhanced.


Increased risk of lithium toxicity

Non-steroidal anti-inflammatory drugs

Effect on blood pressure is impaired.

Potassium supplements

Increased risk of potassium toxicity


May increase blood pressure.

Food interactions

It is advised that you follow a low potassium diet. This includes foods such as tomatoes and bananas.

Disease interactions

Consult your doctor before using this drug if you have a kidney disease, a heart condition which your doctor is not aware of, or if you are allergic to ACE-inhibitor drugs.

Overdose action

A small overdose is no cause for concern. In case of intentional large overdose, seek emergency medical attention. Symptoms of an overdose may include dizziness and/or fainting.

Recommended dosage

High blood pressure: 10-40 mg/day as a single dose or in divided doses.


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