PURPOSE: For lung transplant recipients (LTR), preservation of graft function and survival depends on immunosuppression regimens that usually include tacrolimus. Driven by lower incidences of nephrotoxicity, neurotoxicity and anaphylaxis, oral dosing of tacrolimus is favored over intravenous administration. Therefore, delivering tacrolimus to patients suffering from conditions that preclude oral dosing including malabsorption, gastroparesis, or being intubated presents challenges. Anecdotally, dosing tacrolimus sublingually has been used as an alternative to intravenous delivery. We aimed to determine the appropriate dose conversion of oral to sublingual tacrolimus that would achieve similar therapeutic blood levels in LTR.
METHODS: Lung transplant recipients ≥ 18 years of age who transitioned from oral to sublingual dosing of tacrolimus, or vice-versa, between 1/1/2005 and 1/1/2010 were identified. We excluded patients whose creatinine clearance fluctuated ≥ 75% or who had changes in medications that interact with tacrolimus during the transition period. Indication for conversion was recorded. The primary outcome was the dose needed to achieve therapeutic blood levels of tacrolimus using oral versus sublingual administration. Comparisons were made with the paired t test.
RESULTS: 34 lung transplant recipients met study criteria. The mean daily dose of sublingual tacrolimus was 1.6mg (SD±1.1) versus 3.4mg (SD±2.0) for oral tacrolimus (p< 0.005). Blood levels of tacrolimus associated with the sublingual and oral doses were similar (9.3ng/mL ±4.1 versus 8.9ng/ml ±4.3; p=0.6). For paired samples, the ratio of sublingual tacrolimus dose to oral dose was 0.52 (SD±0.3). For 18 of 34 patients (53%) converted to sublingual delivery for gastroparesis or beazors, the ratio of sublingual to oral tacrolimus dose was similar to the ratio in patients without gastroparesis or beazors (0.53 ±0.3 versus 0.51 ±0.4; p=0.9). No adverse effects were seen with sublingual tacrolimus.
CONCLUSION: Sublingual tacrolimus dosed at 50% the oral dose is safe and achieves equivalent blood levels in LTR.
CLINICAL IMPLICATIONS: For LTR unable to take tacrolimus orally, sublingual delivery is an attractive alternative to intravenous administration due to superior toxicity profile, viability for use in the outpatient setting, and decreased cost.
DISCLOSURE: Katherine Hanger, No Financial Disclosure Information; No Product/Research Disclosure Information