Evaluation of prescribing and patient use of target-specific oral anticoagulants in the outpatient setting.

Abstract

Pharmacist-managed anticoagulation programmes have been shown to improve appropriate use of warfarin, but few programmes have included the new target-specific oral anticoagulants (TSOACs) in their protocols. A greater understanding of TSOAC prescribing, monitoring and administration is needed to identify common errors in the current outpatient practice. The objective of this study is to assess the rate of errors related to prescribing, baseline monitoring and patient administration of TSOACs. A retrospective chart review was conducted to identify patients on TSOAC therapy in each of four outpatient practice sites. Data were abstracted to include TSOAC indication, dosage and frequency prescribed, pertinent past medical history, and laboratory monitoring obtained at the time of TSOAC initiation. In addition, patients were contacted by telephone to assess TSOAC adherence, storage, administration and incidence of adverse events. A total of 395 patients were included in the evaluation. Prescribers did not obtain baseline laboratory values within 1week before or after the time of TSOAC initiation for a majority of study patients. At the time of TSOAC initiation, two patients had abnormally elevated alanine aminotransferase, six had elevated total bilirubin, and 43 had low haemoglobin. A majority (61%) of study patients were prescribed an appropriate TSOAC dose based upon their indication and renal function; however, dosing accuracy could not be determined for all patients as baseline serum creatinine was not obtained by prescribers for 148 patients (37%) at the time of prescribing. TSOACs were dosed inappropriately according to baseline serum creatinine in six patients, and two patients receiving treatment for venous thromboembolism were maintained on a high dose of rivaroxaban for an inappropriate duration. A total of 157 (40%) patients were available by phone and agreed to answer questions regarding their current TSOAC use. Twenty-four patients (23%) reported taking rivaroxaban inappropriately without food, and six patients (14%) endorsed inappropriate storage of dabigatran. Ten patients (6%) reported missing at least one TSOAC dose per week, and 25 (16%) described minor bleeding with their TSOAC. Inappropriate prescribing, monitoring and administration of TSOACs occurred frequently in patients not formally enrolled in an anticoagulation monitoring programme. These results indicate a need for more thorough patient education at the time of TSOAC initiation, as well as improved prescriber education regarding recommended TSOAC dosing and monitoring.