Drug interactions with Warfarin

Q: 57-year-old male with a history of atrial fibrillation and stable for the last few years on his medications, including warfarin, is admitted to the ICU with gastrointestinal bleeding (GIB). The patient visited his PCP 2 weeks ago for insomnia and was prescribed an off-label antidepressant for better sleep. Which medicine is probably the culprit? 

 Answer: Trazodone 

 Trazodone is widely used as an anti-insomnia medication off-label, but a few major dangers associated with it are worth considering 

•  Serotonin syndrome 
•  Cardiac arrhythmias due to prolongation of the QT interval 
• Increased risk of bleeding, particularly when used with NSAIDs, warfarin, antiplatelet, and anticoagulant medications 
• Priapism 
• Mania or hypomania 

 #pharmacology 

 References: 

Po AL. Antidepressants and upper gastrointestinal bleeding. BMJ. 1999 Oct 23;319(7217):1081-2. doi: 10.1136/bmj.319.7217.1081. PMID: 10531078; PMCID: PMC1116881.