Major
Clopidogrel × Esomeprazole
Antiplatelet agents – P2Y12 receptor inhibitors×Drugs for peptic ulcer and GORD. Proton pump inhibitors
Mechanism
Esomeprazole inhibits CYP2C19, the key enzyme that converts clopidogrel to its active metabolite. Active clopidogrel levels fall by about 35%, weakening antiplatelet effect.
Symptoms
The patient feels no symptoms – the weakened antiplatelet effect is silent. The combination raises recurrent myocardial infarction and stent thrombosis risk in patients with prior stenting or acute coronary syndrome.
Management
Replace esomeprazole with pantoprazole (minimal CYP2C19 impact). Among other PPIs, rabeprazole is an alternative. If a PPI is not required, switch to famotidine (H2-blocker) or stop acid suppression.