clarithromycin and dabigatran

Clarithromycin is a potent inhibitor of P-glycoprotein (P-gp), an efflux transporter responsible for intestinal absorption and renal secretion of dabigatran. Inhibition of P-gp increases dabigatran bioavailability and reduces its renal clearance, leading to elevated plasma concentrations.

Increased dabigatran levels can cause significant bleeding, including gastrointestinal bleeding and intracranial haemorrhage. The risk is greatest in patients with renal impairment or those taking higher dabigatran doses.

Avoid co-prescription. If combination is essential, consider reducing the dabigatran dose and monitor closely for signs of bleeding; alternatively, choose an antibiotic that does not inhibit P-gp (e.g., azithromycin or doxycycline). Consult local guidelines for dabigatran dose adjustment in renal impairment.

Interaction is well documented in pharmacokinetic studies and case reports. The summary of product characteristics for dabigatran lists clarithromycin as a P-gp inhibitor that may increase dabigatran exposure. Concomitant use is generally cautioned or contraindicated depending on formulation and renal function.