The INR trend shows a progressive rise from 2.4 to 5.8 after TMP-SMX initiation, with new bruising and melena. This indicates a significant drug interaction causing supratherapeutic anticoagulation and possible gastrointestinal bleeding. The nurse must hold warfarin and notify the provider immediately.
Quick answer Hold warfarin and notify the provider immediately.
Why this is correct INR 5.8 with melena and bruising indicates supratherapeutic anticoagulation with active bleeding risk. Warfarin must be held and the provider notified for urgent management.
Memory hook INR >5 with bleeding signs: hold warfarin, notify provider, consider vitamin K.
NCLEX decision rule Never administer warfarin when serious bleeding is suspected.
Why the alternatives are wrong Reducing the dose or waiting to recheck INR delays needed intervention and risks further bleeding.
Sources
1NCSBN 2026 NCLEX-RN Test Plan
2DailyMed Warfarin Search
A 68-year-old client with atrial fibrillation is managed with warfarin. The client reports new easy bruising and dark, tarry stools. The client recently completed a 5-day course of trimethoprim-sulfamethoxazole (TMP-SMX) for a urinary tract infection. The nurse reviews the following data.
TMP-SMX — Trimethoprim-sulfamethoxazole, an antibiotic that inhibits warfarin metabolism, increasing INR and bleeding risk.