Mr. Martini is a 75-year-old man who has arrived in your ED for urinary frequency and dysuria with no systemic symptoms. He is on the following medications:
He is started on trimethoprim-sulfamethoxazole with no advice about monitoring.
Four days later he’s back with an exsanguinating nosebleed, an INR of 7, requiring Prothrombin Complex Concentrate, and transfusion.
- What do you think happened?