Last reviewed 2026-04-20 · How we verify

Monopril (FOSINOPRIL)

Monopril works by blocking the conversion of angiotensin I to angiotensin II, a potent vasoconstrictor.

Monopril (Fosinopril) is a small molecule Angiotensin Converting Enzyme Inhibitor (ACE inhibitor) developed by Bristol Myers Squibb. It targets the angiotensin-converting enzyme to treat chronic heart failure and hypertensive disorders. Monopril was FDA approved in 1991 and is now off-patent with multiple generic manufacturers. As an ACE inhibitor, it works by relaxing blood vessels to lower blood pressure and reduce strain on the heart. Its commercial status allows for generic competition.

At a glance

Mechanism of action

Mechanism of Action. In animals and humans, fosinopril sodium is hydrolyzed by esterases to the pharmacologically active form, fosinoprilat, specific competitive inhibitor of angiotensin-converting enzyme (ACE).ACE is peptidyl dipeptidase that catalyzes the conversion of angiotensin to the vasoconstrictor substance, angiotensin II. Angiotensin II also stimulates aldosterone secretion by the adrenal cortex. Inhibition of ACE results in decreased plasma angiotensin II, which leads to decreased vasopressor activity and to decreased aldosterone secretion. The latter decrease may result in small increase of serum potassium.In 647 hypertensive patients treated with fosinopril alone for an average of 29 weeks, mean increases in serum potassium of 0.1 mEq/L were observed. Similar increases were observed among all patients treated with fosinopril, including those receiving concomitant diuretic therapy. Removal of angiotensin II negative feedback on renin secretion leads to increased plasma reni

Approved indications

• Hypertension
• Heart Failure

Boxed warnings

• WARNING: FETAL TOXICITY • When pregnancy is detected, discontinue fosinopril sodium tablets as soon as possible. • Drugs that act directly on the renin-angiotensin system can cause injury and death to the developing fetus. See WARNINGS, Fetal TOXICITY

Common side effects

• Cough
• Dizziness
• Nausea/Vomiting
• Headache
• Diarrhea
• Fatigue
• Musculoskeletal Pain
• Hypotension
• Chest Pain
• Upper Respiratory Infection
• Subjective Cardiac Rhythm Disturbance
• Weakness

Drug interactions

• Diuretics
• Potassium-sparing diuretics, potassium supplements, potassium-containing salt substitutes, other drugs that raise serum potassium levels
• Lithium
• Antacids (aluminum hydroxide, magnesium hydroxide, simethicone)
• Injectable gold (sodium aurothiomalate)
• Non-steroidal anti-inflammatory agents (NSAIDs), including selective COX-2 inhibitors
• mTOR inhibitors (e.g., temsirolimus)
• Dual blockade of the Renin-Angiotensin System (RAS) with angiotensin receptor blockers, ACE inhibitors, or aliskiren

Key clinical trials

• Association of Angiotensin-Converting Enzyme Inhibitors and Angiotensin Receptor Blockers With Post-Stroke Pneumonia: A Real-World Retrospective Cohort Study
• Effect of Sacubitril/Valsartan on Cardiac Function in Hypertensive Patients Stratified by BMI: A Real World Study
• Chronic Angiotensin Converting Enzyme Inhibitors in Intermediate Risk Surgery (PHASE4)
• NT-proBNP Selected Prevention of Cardiac Events in Diabetic Patients (PHASE4)
• ACEI or ARB and COVID-19 Severity and Mortality in US Veterans
• Coronavirus (COVID-19) ACEi/ARB Investigation (PHASE4)
• ACE-Inhibitor Effects on Total Hip and Knee Arthroplasty Patients (NA)
• Is There an Adverse Drug Reaction Between Renin-Angiotensin System Blockade and Inhaled Anesthetics (PHASE4)

Primary sources

Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.

Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:

• Monopril CI brief — competitive landscape report
• Monopril updates RSS · CI watch RSS