Can tacrolimus (TAC) be given in a single dose instead of 2 divided doses? We have a patient who has persistently had trough TAC levels of > 10 ng/mL on a dosage of 0.5 mg 2 times daily. The patient had TAC nephrotoxicity in the early postoperative period when her trough levels went > 30 ng/mL on the starting dose of 0.2 mg/kg/day.
Ashish Sharma, MD
Even before we began our preconditioning/immunosuppression minimization protocol, we had a small number of patients who required conversion from twice-daily to once-daily immunosuppression. In fact, the longest surviving kidney recipient on TAC, who is 15 years out, is on once-daily TAC dosing. You could certainly try to switch your patient on 0.5-mg oral TAC twice daily to 1-mg oral TAC daily, and if that is toxic, you could decrease the dose.
A couple of side issues: Fujisawa does not make a solution of TAC, but many pharmacies, including ours, make an oral suspension when there is a need to administer fractional doses of a milligram, such as with lung transplant recipients who are on chronic itraconazole or clarithromycin therapy. The most extreme situation is in HIV-positive transplant recipients who are on a protease inhibitor; I have a patient on 0.1 mg every 4 days (he was toxic on 0.1 mg every 3 days!).
You are absolutely correct to be using the levels to guide therapy.