Imidapril

Imidapril is an angiotensin-converting enzyme inhibitor (ACE inhibitor) used in the treatment of hypertension and heart failure. It works by inhibiting the enzyme responsible for the conversion of angiotensin I to angiotensin II, a potent vasoconstrictor. By blocking this conversion, imidapril effectively reduces blood pressure and alleviates the workload on the heart.

Medical Uses

Imidapril is primarily used for the management of hypertension, either alone or in combination with other antihypertensive agents. It is also indicated for the treatment of congestive heart failure, improving symptoms and reducing hospitalizations related to heart failure. Additionally, imidapril may be used in patients with left ventricular dysfunction following myocardial infarction to improve survival rates and reduce the risk of heart failure.

Mechanism of Action

As an ACE inhibitor, imidapril inhibits the angiotensin-converting enzyme, which is responsible for converting angiotensin I to angiotensin II. Angiotensin II is a potent vasoconstrictor that also stimulates the release of aldosterone from the adrenal glands, leading to increased sodium and water retention. By inhibiting the production of angiotensin II, imidapril decreases vasoconstriction and aldosterone-mediated volume expansion, thereby lowering blood pressure and reducing the workload on the heart.

Pharmacokinetics

Imidapril is administered orally and is absorbed from the gastrointestinal tract. It undergoes hydrolysis in the liver to form imidaprilat, the active metabolite, which is responsible for the drug's antihypertensive effects. The onset of action occurs within 1-2 hours after administration, with peak effects observed at 6-8 hours. The duration of action extends beyond 24 hours, allowing for once-daily dosing. Imidapril and its metabolites are primarily excreted through the kidneys.

Adverse Effects

Common adverse effects of imidapril include cough, dizziness, headache, and fatigue. Less frequently, patients may experience hyperkalemia, renal impairment, and angioedema. As with other ACE inhibitors, imidapril is contraindicated in patients with a history of angioedema related to previous ACE inhibitor therapy and in those with hereditary or idiopathic angioedema.

Contraindications

Imidapril is contraindicated in patients with a history of angioedema associated with previous ACE inhibitor therapy, hereditary or idiopathic angioedema, and in patients with bilateral renal artery stenosis or renal artery stenosis in a solitary kidney. It should be used with caution in patients with severe renal impairment and in those undergoing major surgery or during anesthesia with agents that produce hypotension.

Drug Interactions

Imidapril may interact with other medications, including diuretics, potassium supplements, potassium-sparing diuretics, and nonsteroidal anti-inflammatory drugs (NSAIDs), which can increase the risk of hyperkalemia and renal impairment. Concurrent use with lithium can lead to increased lithium concentrations and toxicity. It is also important to monitor blood pressure closely when imidapril is co-administered with other antihypertensive agents to avoid excessive hypotension.

Conclusion

Imidapril is an effective ACE inhibitor for the management of hypertension and heart failure. Its mechanism of action involves the inhibition of angiotensin II production, leading to vasodilation and reduced aldosterone secretion. While generally well-tolerated, it is important to be aware of potential adverse effects and drug interactions. Patients should be monitored closely for signs of angioedema, hyperkalemia, and renal impairment.