Development of ximelagatran (Exanta), an oral direct thrombin inhibitor, has been stopped in the United States. The drug, which held promise as a replacement for warfarin in many patients, also will be withdrawn from the market in Europe and South America.

The withdrawal was prompted by new reports of serious liver injury noted in the EXTEND clinical trial. This trial studied the use of the drug for venous thromboembolism prophylaxis in orthopedic surgery patients for up to 35 days postoperatively. Reversible elevations in liver function tests (LFTs) had been noted in short-term trials, prompting AstraZeneca to recommend regular LFT monitoring during treatment.

Signs and symptoms of liver injury began in the weeks following the end of 35 days of treatment in the long-term trial. The results suggested that recommended monitoring of liver function during therapy might not be enough to eliminate the risk of liver injury.

Dr. Garrett is a clinical pharmacist practitioner at Cornerstone Health Care in High Point, NC.