Sertraline × Warfarin

Sertraline (SSRI) blocks serotonin reuptake into platelets, depleting the platelet serotonin pool and impairing primary haemostasis. Even with a stable INR, GI bleeding risk roughly doubles in warfarin-treated patients.

Gum bleeding, epistaxis, bruising without trauma, blood in urine or stool, menorrhagia. Severe cases include gastrointestinal or intracranial haemorrhage. Risk rises in patients over 65 and with prior peptic ulcer disease.

The combination is acceptable. PPI cover with pantoprazole and more frequent INR checks (every 2–4 weeks in the first month) are advisable. Alternative antidepressants with minimal platelet effect: mirtazapine or agomelatine.