RESUMO
STUDY OBJECTIVE: To evaluate clinical and safety outcomes among transplant recipients whose tacrolimus was converted from the brand-name formulation to a generic formulation. DESIGN: Retrospective analysis. DATA SOURCE: Clinical databases and electronic records from a large, integrated health care system in California. PATIENTS: A total of 234 clinically stable, adult transplant recipients (renal, liver, and heart) whose tacrolimus was converted from the brand-name formulation to a generic formulation between October 1, 2010, and December 31, 2010, according to a physician-approved protocol. MEASUREMENTS AND MAIN RESULTS: For each patient, pre- and postconversion tacrolimus trough concentrations and serum creatinine concentrations were analyzed. Data were also collected on the percentage of patients who required dosage titration, drug cost savings, and rates of reversion to brand-name tacrolimus, biopsy-proved acute allograft rejections, and mortality. No significant differences were noted in mean ± SD pre- and postconversion tacrolimus trough levels (6.74 ± 1.61 vs 6.96 ± 2.31 ng/ml, p=0.137) or serum creatinine concentrations (1.33 ± 0.48 vs 1.36 ± 0.82 mg/dl, p=0.302). The mean ± SD percent change in tacrolimus trough concentration was 5.63 ± 32.95%. Thirty-six patients (15.4%) required dosage titration. Six patients (2.6%) reverted back to brand-name tacrolimus. No deaths or acute rejections occurred. Use of the generic product saved each patient an average of $45/month in drug acquisition cost and $26/prescription copayment. CONCLUSION: Clinical experience as well as research data show that use of generic tacrolimus results in trough concentrations that are comparable to the brand-name drug. Given the lack of adverse events reported and the cost savings recognized, conversion from brand-name tacrolimus to generic tacrolimus should be encouraged. Since dosage titration may be required, close therapeutic drug monitoring is recommended.