DOI: 10.1097/txd.0000000000001987 ISSN: 2373-8731

Impact of Azole Antifungals on the Conversion Ratio of Immediate-release Tacrolimus to LCP-Tacrolimus Tablets in Non–kidney Solid Organ Transplant Recipients

Stefani Lucarelli, Alicia Lichvar, Thu Le, Janice Kerr, Jade Kozuch, Shirley M. Tsunoda, Ashley Feist

Background.

There are limited data on the impact of azole antifungal use on the appropriate dose conversion strategy from immediate-release tacrolimus (IR-Tac) to once-daily extended-release tacrolimus (LCP-Tacro tablets [LCPT]). The purpose of this study was to determine whether the initial IR-Tac–to-LCPT conversion ratio is affected by azole antifungal use.

Methods.

This single-center, retrospective cohort study included adult non–kidney transplant recipients who were converted from IR-Tac to LCPT between 2015 and 2022. Patients were grouped by azole antifungal use. The primary outcome was the IR-Tac–to-LCPT conversion ratio for those at goal tacrolimus trough, stratified by azole antifungal use. Secondary outcomes included conversion indications, acute kidney injury, neurological adverse effects, and rejection.

Results.

A total of 113 transplant recipients were included (liver 23 [20.4%], heart 70 [61.9%], lung 9 [8.0%], and multiorgan 11 [9.8%]). Twenty-two patients (19.5%) were on azole antifungals. A larger proportion of lung transplant recipients were on azole therapy compared with non–lung allograft recipients (27.3% versus 3.3%, P  = 0.004). Conversion ratios were significantly higher for patients on azoles at 7 d ( P  = 0.031), 30 d ( P  = 0.038), and 90 d ( P  = 0.001). Azole use was associated with lower LCPT doses at 7 d. There was no difference in patients at goal concentration or in the incidence of acute kidney injury between cohorts. Neurologic adverse effects related to IR-Tac prompted conversion in 55 patients, with 79.3% reporting improvement on LCPT.

Conclusions.

LCPT may be safely used in non–kidney transplant recipients regardless of azole antifungal use. Patients converting from IR-Tac to LCPT taking azole antifungals may warrant a higher dose conversion ratio, closer to 1, to achieve comparable tacrolimus trough concentrations.

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