NSAIDs have the largest evidence base and among the strongest guideline endorsements of any OA treatment. ACR 2019 and OARSI 2019 both strongly or conditionally recommend them; NICE makes them first or second line. This comparison is specifically about long-term, continuous NSAID use — where risks accumulate over time — and where LDRT, as a non-systemic treatment, offers a different risk-benefit balance.
The Coxib and traditional NSAID Trialists' (CNT) Collaboration meta-analysis (Bhala N et al., Lancet, 2013) pooled individual patient data from 280 trials. Key findings:
Nissen SE et al. (NEJM, 2016): head-to-head RCT of celecoxib vs naproxen vs ibuprofen in 24,081 patients with OA or RA. Renal events: 0.7% celecoxib / 0.9% naproxen / 1.1% ibuprofen over median 34 months. New hypertension: celecoxib 10% / naproxen 19% / ibuprofen 23%.
OARSI 2019 explicitly recommends against NSAIDs of any class in patients with cardiovascular comorbidity, and strongly recommends against COX-2 selective inhibitors at Level 5 in that group. Also recommends against NSAID use in gastrointestinal comorbidity and frailty. This defines where a non-systemic option becomes most relevant: the patient with OA and cardiovascular disease, prior GI bleed, chronic kidney disease, or frailty — a large proportion of older adults with OA.
Topical diclofenac (gel or patch) has approximately 6–10% systemic bioavailability versus oral formulations. The cardiovascular, GI, and renal risks above are primarily attributable to systemic NSAID exposure. NICE NG226 makes topical NSAIDs first line for knee and hand OA — before considering oral agents. ACR strongly recommends topical NSAIDs for knee OA. OARSI Level 1A for knee OA. For patients who need localized relief without systemic NSAID risk, topical diclofenac is the appropriate first pharmacologic step.
Chronic OA requires long-term management and systemic NSAID risks are elevated; patient has cardiovascular disease, renal insufficiency, GI history, or anticoagulation; NSAIDs have provided inadequate relief; the goal is sustained relief without daily systemic medication.
NSAIDs can bridge the 4–12 week period after LDRT while its anti-inflammatory response develops. For patients where systemic NSAID risk is elevated, the goal of LDRT is sustained relief that reduces the need for ongoing systemic medication. Topical NSAIDs can generally be continued alongside or after LDRT without concern about systemic interaction.
Related: All comparisons | Am I a candidate? | LDRT radiation safety
Medically reviewed by: Robert Warren Floyd, M.D., Ph.D. — Resident Physician, Radiation Oncology, The University of Texas MD Anderson Cancer Center. Last reviewed: August 2, 2026. Independent personal project — not affiliated with or endorsed by MD Anderson Cancer Center. Funding & independence disclosure.