امرأة عمرها ٧٠ سنة تأخذ وارفارين منذ سنوات لرجفان أذيني، والـINR مستقر بين ٢ و٣. جاءت للعيادة ومعها قائمة أدوية جديدة من زيارة طوارئ الأسبوع الماضي لالتهاب بولي. أي تغيير في أدويتها يجعل الممرض يتوقع ارتفاع INR؟

A 70-year-old woman has taken warfarin for years for atrial fibrillation with INR stable at 2–3. She brings a list of new medicines from an ED visit last week for a urinary infection. Which change makes the nurse expect the INR to rise?

1. Eating a consistent daily amount of spinach
2. Starting rifampicin for TB
3. Starting daily vitamin K supplements
4. Starting an antibiotic such as ciprofloxacin

Answer: D) Starting an antibiotic such as ciprofloxacin. Many antibiotics (ciprofloxacin, metronidazole, co-trimoxazole) raise INR. Vitamin K and rifampicin lower it, and leafy greens in a consistent amount do not cause swings.