Search. Learn. Save

Platform for Pharmaceutical Products for Healthcare Professionals
Search By
☰ Generic Formulas

Generic Formulas X

Imidapril

Imidapril: A Comprehensive Guide to the ACE Inhibitor for Hypertension and Heart Health

Introduction

Imidapril is a medication primarily used to manage high blood pressure (hypertension) and heart failure. It belongs to a class of drugs known as angiotensin-converting enzyme (ACE) inhibitors, which work by relaxing blood vessels, thereby reducing the workload on the heart. With cardiovascular disease continuing to be a leading cause of morbidity and mortality globally, understanding the role and benefits of medications like imidapril is essential for both healthcare professionals and patients.

Imidapril

Imidapril is a long-acting ACE inhibitor that is administered orally in its prodrug form—imidapril hydrochloride. Once ingested, it is metabolized in the liver into its active form, imidaprilat, which exerts the therapeutic effects.

Chemical and Pharmacokinetic Profile

  • Chemical class: Dicarboxylate-containing ACE inhibitor

  • Bioavailability: Approximately 42%

  • Time to peak concentration: 6–8 hours after dosing

  • Half-life: Around 2 hours for imidapril and 7–9 hours for imidaprilat

  • Elimination: Primarily renal

Imidapril is usually taken once daily due to its long duration of action, making it a convenient option for many patients.

Mechanism of Action

Imidapril works by inhibiting the enzyme angiotensin-converting enzyme (ACE), which is responsible for converting angiotensin I to angiotensin II—a potent vasoconstrictor. Angiotensin II also stimulates the secretion of aldosterone, which promotes sodium and water retention, leading to increased blood pressure.

By blocking this pathway, imidapril:

  • Decreases the formation of angiotensin II

  • Reduces aldosterone secretion

  • Relaxes arterial smooth muscle

  • Promotes diuresis and natriuresis

  • Ultimately lowers blood pressure and reduces cardiac workload

Indications

1. Hypertension (High Blood Pressure)

Imidapril is primarily indicated for the treatment of essential hypertension, either as monotherapy or in combination with other antihypertensive agents, such as calcium channel blockers or diuretics.

2. Congestive Heart Failure (CHF)

Imidapril is used as an adjunctive treatment in patients with symptomatic heart failure, particularly when diuretics and beta-blockers alone are insufficient.

3. Diabetic Nephropathy and Proteinuria

Though not always a first-line choice, imidapril and other ACE inhibitors are sometimes used in patients with proteinuric kidney disease, especially those with diabetic nephropathy, as they reduce intraglomerular pressure and protein excretion.

Dosage and Administration

The dosage of imidapril varies depending on the condition being treated and patient-specific factors such as age, renal function, and concurrent medications.

Usual Dosing

  • Hypertension:

    • Starting dose: 5 mg once daily

    • Maintenance dose: 5–10 mg once daily

    • Maximum dose: 10–20 mg per day

  • Heart failure:

    • Lower starting doses (e.g., 2.5 mg daily) are often used due to the risk of hypotension.

Special Populations

  • Elderly: May require dose adjustment due to decreased renal clearance.

  • Renal impairment: Dose must be reduced; regular monitoring of renal function is essential.

  • Hepatic impairment: Caution is advised due to the hepatic metabolism of the prodrug.

Imidapril should be taken at the same time each day, with or without food.

Side Effects

As with other ACE inhibitors, imidapril is generally well-tolerated, but it can cause a range of adverse effects.

Common Side Effects

  • Dry cough (due to increased bradykinin levels)

  • Fatigue

  • Headache

  • Dizziness or lightheadedness (especially after the first dose)

Serious but Rare Side Effects

  • Angioedema: Swelling of the face, tongue, or throat, potentially life-threatening.

  • Hyperkalemia: Elevated potassium levels, particularly in patients on potassium-sparing diuretics or supplements.

  • Renal impairment: Especially in those with pre-existing kidney disease or dehydration.

  • Severe hypotension: Especially after the first dose in volume-depleted individuals.

Contraindications and Cautions

Contraindications

  • History of angioedema associated with previous ACE inhibitor use

  • Pregnancy: Can cause fetal toxicity; contraindicated in the second and third trimesters

  • Bilateral renal artery stenosis

  • Severe renal impairment without specialist supervision

Cautions

  • Close monitoring is needed in patients with renal dysfunction, electrolyte imbalances, or those on diuretics.

  • Monitor blood pressure, renal function, and potassium levels regularly during treatment.

Drug Interactions

Imidapril can interact with several medications, leading to enhanced toxicity or reduced efficacy.

Major Interactions

  • Potassium-sparing diuretics (e.g., spironolactone): Increased risk of hyperkalemia

  • NSAIDs: May reduce the antihypertensive effect and worsen kidney function

  • Lithium: Increased risk of lithium toxicity

  • Diuretics: May increase the risk of first-dose hypotension

Clinical Efficacy

Multiple clinical trials and real-world data support the efficacy of imidapril in lowering blood pressure and improving cardiovascular outcomes.

Key Findings

  • Significant reduction in systolic and diastolic blood pressure

  • Improvements in left ventricular function in patients with heart failure

  • Reduction in albuminuria in diabetic and non-diabetic patients with kidney disease

  • Comparable efficacy to other ACE inhibitors like enalapril and ramipril

A 12-week randomized trial comparing imidapril with ramipril showed that both agents achieved similar blood pressure control, but imidapril was better tolerated in terms of cough incidence.

Imidapril vs. Other ACE Inhibitors

Imidapril shares many pharmacological properties with other ACE inhibitors but has some unique aspects.

Feature Imidapril Enalapril Ramipril
Dosing frequency Once daily Once or twice daily Once daily
Cough incidence Lower Moderate Moderate
Time to peak effect 6–8 hrs 4–6 hrs 3–6 hrs
Active metabolite Imidaprilat Enalaprilat Ramiprilat

Although not as widely used as enalapril or ramipril, imidapril remains a strong option, especially in patients experiencing side effects with other ACE inhibitors.

Use in Special Conditions

Heart Failure

Imidapril helps reduce preload and afterload, improving symptoms and exercise tolerance in heart failure patients.

Chronic Kidney Disease (CKD)

Like other ACE inhibitors, imidapril may help delay progression of CKD by reducing glomerular hypertension and proteinuria.

Diabetes Mellitus

Imidapril offers both blood pressure control and renal protection, making it particularly beneficial for diabetic patients with microalbuminuria.

Patient Tips

  • Take the medication exactly as prescribed.

  • Report any signs of swelling, difficulty breathing, or persistent dry cough to your doctor.

  • Avoid salt substitutes high in potassium.

  • Stay hydrated and monitor blood pressure regularly.

  • Inform your healthcare provider about any over-the-counter medications or supplements you're using.

Conclusion

Imidapril is a potent and well-tolerated ACE inhibitor with proven benefits in managing hypertension, heart failure, and kidney disease. Though less commonly prescribed than other ACE inhibitors, it offers advantages in dosing convenience and a lower risk of certain side effects like dry cough. As with all medications, the choice of therapy should be individualized, taking into account patient-specific factors, comorbid conditions, and tolerability. Imidapril represents a valuable tool in the therapeutic arsenal against cardiovascular and renal diseases, promoting better outcomes and quality of life for many patients worldwide.