Conversion From Immediate-Release to Prolonged-Release Tacrolimus in Kidney Transplant Patients With Tremor: A Case Series Study.

Background/aim: Tremor is common with tacrolimus treatment and is linked with peak blood drug concentrations. We investigated the effect of switching from immediate-release tacrolimus (IR-TAC) to MeltDose prolonged-release tacrolimus (LCPT) on tremor in kidney transplant recipients experiencing tremor at therapeutic levels of IR-TAC.

Methods: The Activities of Daily Living Subscale (ADL, range 0-48, lower = better) of the Essential Tremor Rating Scale was used to assess the effect of therapy change on speech, occupational impairment and social activities over a 12-month follow-up period.

Results: The study included 18 patients (mean age = 45.6 y, range 26-73; median (IQR) time from transplant = 1.1 y (0.6-1.5), with baseline IR-TAC trough concentrations (C) ranging from 4.2 to 9.4 ng/mL (mean C = 6.7 ± 1.3 ng/mL). After the switch to LCPT, the mean ADL score improved from baseline 11.2 to 8.4 after 7 to 14 days (an 18% improvement, P < .001). This improvement was sustained after 3 months (ADL score = 5.0, 46% improvement vs baseline), 6 months (ADL score = 4.4, 48% improvement vs baseline), and 12 months (ADL score = 3.6, 63% improvement vs baseline); all P < .001. Despite a 40% reduction in LCPT daily doses (mean -1.9 mg/day compared to IR-TAC), the achieved C was constant during the course of the 12-month observation (P = .755). The renal function remained stable after conversion (eGFR 12 months vs baseline = +1.1 mL/min/1.73 m, 95% CI: -5.6 to +7.9).

Conclusion: Conversion to LCPT may alleviate symptom burden and improve daily activities in kidney transplant recipients experiencing tremor within therapeutic IR-TAC concentrations.