New Xarelto Safety Warning Issued

October 18, 2018

ISMP reports that some patients have inadvertently taken double doses of rivaroxaban in dosing mixups.

Some patients are mistakenly receiving double doses of the direct oral anticoagulant rivaroxaban (Xarelto), the Institute for Safe Medication Practices (ISMP) warns.

Physicians typically prescribe 15 mg of rivaroxaban twice daily initially for patients with deep vein thrombosis and pulmonary embolism. Then, after three weeks on that dose, the patient is switched to 20 mg once daily for the remainder of treatment, ISMP wrote in its September 2018,

newsletter.

However, ISMP has received reports in which patients are mistakenly taking both doses concurrently.

For example, an elderly patient was given two rivaroxaban scripts at a visit to his clinic: rivaroxaban 15 mg twice daily for 21 days and rivaroxaban 20 mg daily with a start date of 21 days later.

However, both prescriptions were dispensed at the same time by a community pharmacy, and the patient took both scripts for three weeks-until the patient was rushed to the hospital for subdural hematoma.

The hospital noted a few factors that contributed to the event, including insufficient patient education at the time of dispensing. In addition, the labeling of the 20 mg daily prescription did not clearly indicate that the medication should not be taken until the 15 mg twice daily script was completed, ISMP writes in its newsletter.

In addition, there was limited use of the manufacturer’s (Janssen Pharmaceuticals) starter pack, which guides patients to proper dosing for the first 30 days of treatment.

“While it may be convenient for both prescriptions to be issued and dispensed at the same time, the safety of his practice is in question,” ISMP writes. Ideally, the 20 mg dose should not be communicated to the pharmacy until a few days before it is to start, according to ISMP.

“If prescribers must prescribe both dosing regimens at the same time, provide clear directions to the patient and ensure they are understood,” ISMP writes. Prescribers should include instructions that the 20 mg tablets should be taken after the 15 mg supply is exhausted (21 days).

In addition, prescribers should include the statement, “Begin after [date],” in the Xarelto 20 mg instructions.

“Pharmacists should make sure the patient has received these explicit instructions verbally and in writing,” ISMP writes.

Payer systems should also have an automated method to decline payment for prescriptions that may cause an overdose-such as rivaroxaban, according to ISMP.