Acetylsalicylic acid × Venlafaxine

Venlafaxine inhibits the reuptake of serotonin and noradrenaline. Platelets low in serotonin are worse at stopping bleeding, and the venlafaxine label describes bleeding from bruising and nosebleeds to life-threatening gastrointestinal haemorrhage. Aspirin irreversibly blocks platelet cyclooxygenase and injures the stomach lining, so together the drugs raise the risk of bleeding (Spanish and US venlafaxine labels).

Gum bleeding, epistaxis, bruising without trauma, black or tarry stools. Severe cases: GI bleeding.

The combination can be used with caution: the venlafaxine SmPC asks for caution in patients taking platelet inhibitors, and aspirin is one of them. The US Food and Drug Administration (FDA) requires prescribers to warn patients about the higher bleeding risk when venlafaxine is combined with aspirin (venlafaxine FDA label). Explain the signs of bleeding to the patient in advance: bruising without injury, nosebleeds, black stools, vomiting blood. With black stools, vomiting blood or any other sign of gastric bleeding, the patient stops aspirin and sees a doctor at once (aspirin 100 mg SmPC).