diclofenac and lisinopril

Diclofenac inhibits prostaglandin synthesis, reducing renal blood flow and glomerular filtration. Lisinopril dilates efferent arterioles via angiotensin II inhibition; combined effects can precipitate acute kidney injury. NSAIDs may also blunt the antihypertensive effect of ACE inhibitors. Both drugs can increase serum potassium.

Reduced antihypertensive efficacy and increased risk of acute kidney injury, particularly in patients with pre-existing renal impairment, volume depletion, or concurrent diuretic use. Hyperkalaemia may also occur. Patients may notice worsening blood pressure control or signs of renal dysfunction such as oedema or fatigue.

Monitor blood pressure and renal function (serum creatinine and potassium) at baseline and within 1 to 2 weeks of starting or changing doses. Consider using a non-NSAID analgesic if possible. If an NSAID is necessary, use the lowest effective dose for the shortest duration. Avoid in patients with chronic kidney disease or dehydration. Adjust lisinopril dose as needed.

Based on well-established pharmacodynamic interactions and documented cases of acute kidney injury. Clinical guidelines advise caution.