Moderate
Apixaban × tacrolimus
Direct oral anticoagulants (factor Xa inhibitors)×Calcineurin inhibitor (immunosuppressant)
Mechanism
Tacrolimus is a weak CYP3A4 inhibitor and P-glycoprotein substrate. P-glycoprotein competition may slightly raise apixaban levels; clinical effect is minimal.
Symptoms
Gum bleeding, epistaxis, bruising without trauma, black or tarry stools, haematuria. Higher risk in older patients, prior peptic ulcer disease, and chronic kidney disease.
Management
No dose adjustment needed. In post-transplant patients with chronic kidney disease, watch for any bleeding signs and check creatinine clearance every 4 weeks — if it falls below 50 mL/min, reduce apixaban to 2.5 mg twice daily.