escitalopram and aspirin

Pharmacodynamic interaction. Escitalopram, a selective serotonin reuptake inhibitor (SSRI), inhibits the serotonin transporter, reducing serotonin concentration in platelets and impairing platelet aggregation. Aspirin irreversibly inhibits cyclooxygenase (COX-1), decreasing thromboxane A2 production, which also impairs platelet aggregation and damages the gastric mucosa. The combined effects result in additive antiplatelet activity and increased bleeding risk, particularly from the upper gastrointestinal tract.

The combination increases the risk of gastrointestinal bleeding, including gastric and duodenal ulcers, which can be severe or life-threatening. The risk is further elevated in patients with a history of peptic ulcer disease, elderly patients, or those taking other anticoagulants or antiplatelet agents. Clinicians should be alert for signs of occult or overt bleeding, such as melaena, haematemesis, or a fall in haemoglobin.

Before co-prescribing, assess the patient's overall bleeding risk and the necessity of each drug. For patients with existing risk factors, consider gastroprotective therapy (e.g., a proton pump inhibitor) and monitor closely for evidence of bleeding. Advise patients to report any unusual bleeding, easy bruising, or black stools. If pain relief is required, alternatives to aspirin (e.g., paracetamol) may be considered where appropriate, but the antiplatelet benefit of aspirin should not be discontinued without specialist advice.

Well-documented in pharmacovigilance databases and clinical studies, with a recognised increased risk of upper gastrointestinal bleeding when SSRIs are combined with antiplatelet agents such as aspirin. The interaction is included in standard drug interaction references and prescribing guidelines.