Rivaroxaban

Regarding rivaroxaban, which one of the following statements is TRUE?

a) It is a new oral direct thrombin inhibitor

b) It is a pro-drug

c) At therapeutic doses, it has a superior effect on venous thromboembolism rate

compared to enoxaparin

d) At therapeutic doses, it produces lower rates of bleeding complications compared to

enoxaparin

e) It has a half-life of two to four hours

Answer: c

Explanation

Rivaroxaban and dabigatran are new anticoagulants that may have an important role

in patient care. They are administered orally, avoiding painful injections and have a

relatively fast onset of action (one to four hours post ingestion). Rivaroxaban is a direct

factor Xa inhibitor and therefore stops the production of thrombin while allowing

existing thrombin to produce haemostasis. Dabigatran is a pro-drug that becomes a

direct thrombin inhibitor and so may stop existing thrombin from contributing

towards clot formation. In therapeutic trials (RECORD trials 1 to 4), rivaroxaban had

a better effect on venous thromboembolism rate than enoxaparin, and had a mildly

raised but not statistically significant rate of bleeding complications. Rivaroxaban’s

half-life is 7 to 9 hours with factor Xa activity not returning to normal for 24 hours,

allowing once-daily dosing. This is important knowledge to have when timing such

activities as surgery or removal of an epidural catheter, as rivaroxaban has no reversal

agent and its effects are difficult to assess through standard laboratory tests.

Reference

RECORD4 Investigators. Rivaroxaban versus enoxaparin for thromboprophylaxis

after total knee arthroplasty (RECORD4): a randomised trial. Lancet 2009; 373(9676):

1673–80.