Comparison of Tacrolimus Serum Levels During First Month After Lung Transplant in Patients with and without Gastroparesis

Abstract

<h3>Purpose</h3> Gastroparesis is suspected to alter the absorption of immunosuppressive medications in solid organ transplant recipients. Limited data exists in lung transplant recipients (LTRs), who typically have high rate of post-transplant gastroparesis. The objective of this study was to compare the post-transplant route of tacrolimus administration and variation in serum tacrolimus levels in LTRs with and without gastroparesis. <h3>Methods</h3> All recipients who underwent lung transplant in 2019 were included. Objective gastric emptying data was documented. Daily tacrolimus dose, route of administration and serum levels for 30 days post-transplant were evaluated and compared. <h3>Results</h3> There were 123 LTRs in 2019, of which 31 (25%) developed gastroparesis. After matching, baseline characteristics were similar amongst the 2 groups, however, gastroparesis patients were younger (54 ±14 vs 59 ±14 years, p<0.05). Majority (118) of patients started with sublingual tacrolimus postoperatively, of which 82 (69%) were switched to the oral route. Patients with gastroparesis had longer duration of sublingual administration compared to patients with normal gastric emptying (median days 14 vs 7, p<0.05) . Median time to reach 10mg/dl serum level was 9 days in gastroparesis patients vs 7 days in non-gastroparesis group. Overall, there was no significant difference in mean serum tacrolimus levels amongst the 2 groups over 30 days (<b>Figure 1</b>). <h3>Conclusion</h3> Gastroparesis is common after lung transplant and may require longer sublingual administration of tacrolimus. Ultimately, however, gastroparesis patients can be switched safely from sublingual to oral tacrolimus as there is no significant difference in the postoperative trend of serum tacrolimus levels, even when accounting for change in route of tacrolimus administration.