Anticoagulation Control of Warfarin in Pharmacist-Led Clinics Versus Physician-Led Clinics: A Prospective Observational Study

Purpose

Warfarin is an affordable drug used for numerous indications, and still a favorable choice for patients with a history of bleeding from direct oral anticoagulants or presence of valvular heart diseases. However, warfarin requires regular international normalized ratio (INR) monitoring for safety and efficacy. Warfarin’s efficacy and safety is correlated with actual time spent within the therapeutic INR. Time in therapeutic range (TTR) is an estimate that measures the percentage of actual time spent within the therapeutic INR. Our aim was to investigate differences in anticoagulation control of warfarin using TTR between pharmacists and other health-care providers.

Methods

This prospective observational study was conducted in an ambulatory-care setting of a tertiary hospital to compare anticoagulation management using TTR between clinics run by pharmacists versus other health-care providers.

Results

A total of 62 patients were enrolled: 33 in the pharmacist-led clinic and 29 in the physician-led clinic. TTR levels were statistically higher among patients in the pharmacist-led clinic than than the physician-led clinic (87.27%±3.82% and 52.48%±5.49%, respectively; p<0.001). For 27 patients followed retrospectively by physicians and prospectively by clinical pharmacists, TTR was statistically higher during clinical pharmacists’ care (91.70%±2.93% versus 61.39%±5.11%, respectively; p<0.001). During the study, approximately 82% of patients reached their target INR in the pharmacist-led clinic compared to 24% in the physician-led clinic.

Conclusion

The findings of our study found that patients followed in the pharmacist-led clinic had higher TTR levels than those followed in the physician-led clinic.

Validated liquid chromatographic determination of 5-fluorouracil in human plasma

A sensitive, reproducible, selective and accurate high performance liquid chromatographic (HPLC) method for the quantitative determination of 5-flurorouracil in plasma has been developed and validated using isocratic elution and UV detection. The method provides a selective quantifications of 5-flurorouracil without any interference of the endogenous uracil. The assay is performed after a double extraction of 5-flurorouracil and thymine (internal standard) from human plasma using ethyl acetate. The drug and the internal standard were eluted from a Genesis C(18) analytical column at ambient temperature with mobile phase consisting of methanol:water (10:90, v/v) adjusted to pH 3.2 with perchloric acid at a flow rate of 1.0 ml/min. The effluent was monitored with an ultraviolet detector at 260 nm. Quantification was achieved by the measurement of the peak-height ratios and the limit of quantification for 5-flurorouracil in plasma was 30 ng/ml. The retention times for 5-flurorouracil, uracil, and thymine were 4.5, 6.0, and 9.0, respectively. The intra-day coefficient of variation (CV) ranged from 1.35 to 4.53% at three different concentrations and the inter-day CVs varied from 1.29 to 4.98%. The relative and absolute recoveries varied from 96 to 101%. Stability tests showed that 5-flurorouracil is stable for at least 72 h in plasma after freezing. The simple method may permit the assessment of 5-flurorouracil plasma concentrations for pharmacokinetic studies in combination with clinical trials.