interactions: ASA/LMWH/SSRIs/NSAIDs/pentoxifylline (additive GI toxicity and increased risk of bleeding), ACEIs/ARBs/BB/loop/thiazides (decreased diuretic and antihypertensive efficacy via decreased renal prostaglandin production), cholestyramine (decreased absorption of diclofenac), most CYP inducers/inhibitors, cyclosporine/tacrolimus (increased risk of cyclosporine, tacrolimus toxicity, unknown mechanism), pemetrexed (decreased renal clearance and increased toxicity of pemetrexed), sulfonylureas (increased risk of hypoglycemia via inhibition of sulfonylurea metabolism), warfarin (both substrates for CYP2C9, competitive metabolism)