Effects of pharmacist counseling on outpatients receiving warfarin at Songklanagarind Hospital

Abstract

Objective: To assess the effects of pharmacist counseling in warfarinized patients in Songklanagarind Hospital. Material and Methods: Comparison of pre- and post-counseling services from February-September 1999. Both verbal and written reinforcement were used for counseling. Results: Data were collected on 97 patients with mitral stenosis (29.9%), mitral valve replacement (43.3%), and atrial fibrillation (26.8%). The numbers of patients whose International Normalized Ratio (INR) was in the therapeutic range for each indication were not statistically different between before and after receiving counseling (p > 0.05). The number of patients with subtherapeutic INRs was greater in those with mitral valve replacement than in the other groups. Minor bleeding was reported more frequently during the counseling service than the pre-counseling period (41 vs 12, p < 0.05). The most common symptoms of bleeding were ecchymosis and gum bleeding. Thromboembolic events during both periods were comparable, 13 vs 15 in post-and pre-counseling periods, respectively. The most common symptoms indicating thromboembolism were paresthesia and syncope. Patients' knowledge of warfarin therapy had increased after receiving the counseling service (p < 0.05). Patient satisfaction toward the counseling service was rated as good in the following areas: general satisfaction, interpersonal manner of pharmacist providing counseling, communication, and accessibility to the service. Conclusion: Pharmacist counseling through verbal and written reinforcement could improve patients' knowledge of warfarin therapy, and may enable the patients to identify complications related to the therapy, particularly minor bleedings. Pharmacist counseling may not be the only factor that could affect the control of INRs and complications related to warfarin therapy.

Keywords

• warfarin
• outpatients
• pharmacist counseling