Sertraline × Warfarin

Sertraline, like other selective serotonin reuptake inhibitors (SSRIs), alters platelet function and raises bleeding risk on its own, from bruising and nosebleeds to life-threatening haemorrhage (US sertraline label, FDA). With warfarin these risks add up (US sertraline label). Sertraline 200 mg a day also produced a small but statistically significant increase in prothrombin time, which in rare cases can change the international normalised ratio (INR) (sertraline SmPC).

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 with monitoring. Check prothrombin time (international normalised ratio, INR) carefully when sertraline is started or stopped (sertraline SmPC). The US Food and Drug Administration (FDA) also advises careful INR monitoring in patients on warfarin (US sertraline label) and close monitoring for signs of bleeding (US warfarin label). Take particular care in patients with a history of bleeding disorders (sertraline SmPC). Warn the patient about the higher bleeding risk and ask them to mention any over-the-counter medicines that add to it, such as aspirin and non-steroidal anti-inflammatory drugs (US sertraline label).