Mechanism of action: inhibition of thrombin (activated Factor II), preventing conversion of fibrinogen to fibrin
Usual oral daily dose: 220 mg once per day
Lower daily dose (150 mg) is indicated in:
(1) patients > 75 years of age
(2) creatinine clearance 30-50 mL/min
(3) if amiodarone or verapamil is prescribed concurrently
Contraindications:
(1) creatinine clearance < 30 mL/min
(2) concurrent therapy with quinidine or ketoconazole (inhibitors of the P-glycoprotein efflux membrane transporter, resulting in accumulation)
(3) concurrent therapy with rifampicin (induces the P-glycoprotein efflux membrane transporter, resulting in increased excretion)
Initial dose, started 1-4 hours after surgery: one half of daily dose
Duration of therapy: 10-14 days following knee arthroplasty, 28-35 days following hip arthroplasty
Monitoring: not usually performed
Effects on screening tests: prolongation aPTT and thrombin time
