- by John Reints
- Jan 24 2026
Trimethoprim-Sulfamethoxazole and Warfarin: What You Need to Know About INR Elevation
Trimethoprim-sulfamethoxazole can dangerously raise INR levels in people taking warfarin, increasing bleeding risk. Learn why this interaction happens, who’s most at risk, safer antibiotic alternatives, and what to do if your INR spikes.