Impact of levofloxacin dose adjustments by dispensing pharmacists on adverse reactions and costs in the treatment of elderly patients

Ensuring an appropriate dosage of renally eliminated drugs for patients with renal insufficiency is important for preventing adverse drug reactions. We investigated the effectiveness of interventions by pharmacists in a hospital pharmaceutical department. The comparative study was performed at Gifu Municipal Hospital in Japan from March to August 2011, and included an intervention (142 patients) and a control group (98 patients). Upon receiving a prescription of levofloxacin for patients aged ≥ 75 years, pharmacists evaluated the patients' kidney function and adjusted the appropriate dosage at the time of dispensation. In the intervention and control groups, levofloxacin-induced adverse reactions developed in 6 of 142 (4.2%) and 13 of 98 (13.3%) patients, respectively (p < 0.05). The cost of reducing levofloxacin per patient was ¥191.1 and ¥0 in the intervention and control groups, respectively. The cost per patient for adverse reaction treatments and examinations was ¥15.5 and ¥290.0 in the intervention and control groups, respectively. The intergroup difference in the total cost per patient was ¥465.6. Dose adjustment of levofloxacin at the time of dispensation by the pharmacist for patients aged ≥75 years resulted in a decrease in the incidence of adverse reactions and cost. These findings can be applied not only to hospitals, but also to community pharmacies, because the intervention, which is a manual system, is simply performed when pharmacists are dispensing drugs.