What NSAID and dose is safest for a 75-year-old with kidney risk?

The short version: no NSAID is "safe" for a 75-year-old with kidney risk. The goal is to use the lowest effective dose for the shortest time with close monitoring.

You are asking about treating pericarditis with an NSAID in a 75-year-old man who already has elevated kidney risk. The best available evidence on older adults comes from a 2000 study of Tennessee Medicaid enrollees aged 65 and older. It found that current prescription NSAID use raised the risk of acute kidney failure by 58% overall [18]. For ibuprofen specifically, the risk climbed with dose: below 1200 mg per day there was no increase, but 1200 to 2400 mg raised the odds by 89%, and over 2400 mg more than doubled them [18].

That same study gives naproxen a better-looking profile: the odds ratio was 1.03, meaning essentially no measurable increase in kidney failure risk [18]. But this is observational data from the late 1980s, and naproxen still carries the same mechanism of harm — it reduces the prostaglandins that keep kidney blood flow up in an older person whose kidneys are already struggling.

A 2013 BMJ study of over 487,000 people found that combining an NSAID with a diuretic and a blood pressure medication (ACE inhibitor or ARB) — a "triple whammy" — raised acute kidney injury risk by 31%, and by 82% in the first 30 days [12]. A 2020 Japanese claims study found that 0.3% of all outpatients were prescribed this triple combination, and those patients had nearly twice the rate of chronic kidney disease [11]. Many elderly patients take at least one of these drugs.

The mechanism is not a mystery: NSAIDs block the COX enzymes that produce prostaglandins. In a kidney that already has reduced blood flow, prostaglandins are what keep the kidney perfused. Take them away and the kidney can shut down, sometimes permanently [8, 18]. This is not idiosyncratic or rare — it is a predictable effect in vulnerable people.

No study in this retrieval tested NSAIDs specifically for pericarditis in men over 70 with kidney risk. The dosing data comes from a general elderly population with various diagnoses. For pericarditis specifically, the ICAP trial (mean age about 50) used aspirin or ibuprofen, not naproxen [2]. A 2025 case report used ibuprofen 1800 mg per day for late-onset pericarditis, but the patient was 55 with no kidney risk noted [2].

My call: if an NSAID is unavoidable, naproxen 250–500 mg twice daily with food has the best kidney safety signal in the elderly [18], but it is still a gamble. The safest strategy is to avoid NSAIDs entirely and treat pericarditis with colchicine alone or with a very short course of a COX-2 inhibitor if gastroprotection is paramount. Confidence: moderate — the best data is 25 years old and observational, no trial has tested this exact question.