A dog on chronic NSAIDs develops vomiting and azotemia; what is the likely mechanism and a safer analgesic alternative?

• A. NSAID-induced nephrotoxicity from reduced renal perfusion; switch to opioids or non-NSAID analgesics and consider GI protection
• B. Liver toxicity; switch to antibiotics
• C. Kidney stone formation
• D. Renal failure due to dehydration

Answer: (A)

NSAIDs can injure the kidneys by blocking protective prostaglandins. Prostaglandins normally keep the afferent arteriole dilated and help maintain renal blood flow and GFR, especially when a patient is dehydrated or volume-overloaded. Inhibition of COX enzymes reduces these prostaglandins, leading to afferent arteriolar constriction, decreased renal perfusion, a drop in GFR, and resulting azotemia. Vomiting is a common systemic sign when NSAID-induced kidney injury occurs, and chronic use raises this risk.

The best management is to stop or avoid NSAIDs and switch to analgesics that don’t impair renal perfusion. Opioids are a good option for pain control in this situation. Other non-NSAID analgesics (such as certain anticonvulsants or gabapentinoids where appropriate) can also be considered, depending on the case and veterinarian’s guidance. If there is any chance NSAIDs will be used again in the future, planning for GI protection (for example, gastroprotectants) is prudent, but the priority here is renal-safe analgesia and addressing the underlying dehydration and renal function.