MajorAntiplatelet agents (low dose) / NSAIDs (analgesic dose)×Non-steroidal anti-inflammatory drugs (NSAIDs)
Updated · Methodology
Mechanism
Diclofenac competitively inhibits platelet cyclooxygenase-1 and blocks aspirin's access for COX-1 acetylation. Co-administration loses aspirin's cardioprotective effect. Additive ulcerogenic effect of two NSAIDs.
Symptoms
Black or tarry stools (melena), vomiting blood or coffee-ground material, epigastric pain. Risk multiplies in older patients and with prior peptic ulcer disease.
Management
If the patient takes aspirin for cardioprotection, give aspirin 30 minutes before or 8 hours after diclofenac. Alternative analgesic without this issue: paracetamol or a selective COX-2 inhibitor (celecoxib).
Check the full regimen, not just this pair
Opens the checker with these two drugs prefilled. Add the rest of the regimen and recompute additive risks.
Summary of a multi-drug list →
Medicine list: everything you take in one place →
Sources
- FDA: Warfarin sodium tablet (Amneal Pharmaceuticals LLC) – Prescribing Information (2017)– ; DailyMed setid 558b7a0d-5490-4c1b-802e-3ab3f1efe760
- AEMPS: Ficha técnica: Diclofenaco (nº registro 62161), sección 4.4 (2025)– AEMPS, CIMA, nº registro 62161, revisión 08/2025, sección 4.4