ibuprofen and perindopril

Ibuprofen inhibits cyclooxygenase, reducing renal prostaglandin synthesis. This causes afferent arteriolar vasoconstriction and decreased renal blood flow, which counteracts the vasodilatory effects of perindopril and reduces its antihypertensive efficacy. Additionally, impaired renal perfusion can lead to reduced glomerular filtration and sodium retention, while the ACE inhibitor may increase potassium levels, so combined use raises the risk of hyperkalaemia.

Concurrent use can reduce the antihypertensive effect of perindopril, potentially leading to uncontrolled blood pressure. More seriously, it increases the risk of acute kidney injury, particularly in patients with pre-existing renal impairment, dehydration, or heart failure. Hyperkalaemia may also occur, especially in those with renal dysfunction or on potassium-sparing agents. The worst plausible outcome is irreversible renal failure.

Avoid concomitant use where possible. If an NSAID is required, use the lowest effective dose for the shortest duration, and consider paracetamol or alternative analgesia. Monitor blood pressure, serum creatinine, and potassium at baseline and within 1 to 2 weeks after starting or stopping the NSAID, then periodically. Ensure adequate hydration, and exercise caution in elderly patients and those with renal impairment. If hypertension worsens or renal function deteriorates, adjust therapy accordingly.

This interaction is well established and documented in drug interaction databases and regulatory warnings. It is based on consistent clinical reports and pharmacological evidence, though the magnitude of effect varies between individuals. Guidelines recommend caution and monitoring when an NSAID is co-prescribed with an ACE inhibitor.