Acetylsalicylic acid × Warfarin

Aspirin irreversibly blocks platelet cyclooxygenase and reduces platelet aggregation. Warfarin blocks vitamin K-dependent clotting factor synthesis. Two different antithrombotic mechanisms add up. Aspirin also damages the gastric mucosa, raising bleeding risk independently of coagulation parameters.

Gum bleeding, epistaxis, black or tarry stools (melena), vomiting blood or coffee-ground material. Severe cases include fatal intracranial haemorrhage. Risk multiplies in patients over 75 and with prior peptic ulcer disease.

The combination is acceptable only for strict indications: after coronary stenting, mechanical heart valves, acute coronary syndrome. Limit triple/dual antithrombotic therapy to 1–6 months based on risk. Aspirin dose: 75–100 mg/day. PPI cover (pantoprazole) is mandatory. Check INR every 2–4 weeks.