Question

A 50 yr old patient with renal insufficiency was recently operated for pyelolithotomy. Which drug will you give for post-operative analgesia?

• A. Diclofenac sodium
• B. Naproxen
• C. Indomethacin
• D. Acetaminophen

Hint:

All NSAIDs are contraindicated in renal insufficiency; choose the analgesic that does not act on COX enzymes.

Answer 1

The Correct Option is D

Step 1: Identify the clinical concern.
The patient has renal insufficiency (pre-existing impaired kidney function) and has undergone pyelolithotomy (surgery on the renal pelvis). Post-operative analgesia must avoid further nephrotoxicity.

Step 2: Analyse each option with respect to renal safety.

• Diclofenac sodium (NSAID): Contraindicated in renal insufficiency. NSAIDs inhibit COX enzymes, reducing prostaglandin-mediated afferent arteriolar dilation, thereby reducing GFR and causing further renal damage. Can precipitate acute kidney injury.
• Naproxen (NSAID): Same mechanism as diclofenac. Contraindicated in renal insufficiency for the same reasons.
• Indomethacin (NSAID): One of the most potent NSAIDs, highly nephrotoxic. Absolutely contraindicated in renal insufficiency.
• Acetaminophen (Paracetamol): Analgesic/antipyretic that works via a different mechanism (not COX inhibition). It is the drug of choice for analgesia in patients with renal insufficiency. It does not affect renal prostaglandins and is safe to use at appropriate doses.

Conclusion: Acetaminophen is the safest analgesic in renal insufficiency as it does not compromise renal blood flow or GFR.