A 58-year-old man with a 10-year history of osteoarthritis presents with severe knee pain. He has been taking ibuprofen 400 mg three times daily for the past 6 months. His past medical history includes hypertension (on amlodipine 5 mg daily) and chronic kidney disease stage 3b (eGFR 38 mL/min/1.73 m²). Today, his blood pressure is 148/92 mmHg, serum creatinine has risen from 1.4 to 1.8 mg/dL over 3 months, and urinalysis shows 1+ proteinuria. Which of the following is the most appropriate next step in NSAID management?

Explanation

## Clinical Context This patient has multiple risk factors for NSAID-induced renal injury: pre-existing CKD stage 3b, hypertension, and prolonged NSAID use. The rising creatinine and new proteinuria indicate NSAID-induced acute kidney injury (AKI) superimposed on chronic kidney disease. ## Why Discontinuation Is Mandatory **Key Point:** NSAIDs are contraindicated in patients with eGFR <30 mL/min, and their use requires extreme caution in stage 3b CKD (eGFR 30–44). This patient's declining renal function over 3 months is a direct consequence of NSAID-induced afferent arteriolar vasoconstriction and reduced glomerular filtration pressure. **High-Yield:** NSAIDs inhibit prostaglandin-mediated renal vasodilation, which is critical for maintaining GFR in patients with renal impairment. In CKD, the kidney becomes "prostaglandin-dependent," making NSAIDs particularly nephrotoxic. ## Why Acetaminophen Is the Safest Alternative - No renal toxicity at therapeutic doses - No prostaglandin inhibition - No fluid retention or hypertension exacerbation - Maximum 3 g/day in CKD (lower than in normal renal function) ## Why Other Options Fail | Option | Reason for Rejection | |--------|---------------------| | Continue ibuprofen + increase amlodipine | Masks the problem; continued NSAID will worsen renal function and hypertension regardless of antihypertensive escalation | | Switch to selective COX-2 inhibitor (celecoxib) | COX-2 inhibitors carry the same renal risk as non-selective NSAIDs in CKD; they do NOT spare the kidney | | Reduce ibuprofen dose | Dose reduction does not eliminate the mechanism of renal injury; any NSAID use in stage 3b CKD with declining function is inappropriate | **Clinical Pearl:** The combination of NSAIDs + ACE inhibitors/ARBs + diuretics ("triple whammy") is especially dangerous; this patient is on amlodipine (not an ACE inhibitor), but the NSAID + hypertension + CKD triad is sufficient to mandate discontinuation. **Mnemonic: NSAID-CKD RED FLAGS** — Renal impairment (eGFR <45), Elevated creatinine trend, Diuretic/antihypertensive use. When all three are present, NSAIDs must be stopped. [cite:KD Tripathi 8e Ch 12]