NAPLEX Practice Question # 79

Which of the following is likely to decrease tacrolimus blood concentration when it is used concomitantly?

(A) Grapefruit juice
(B) Erythromycin
(C) St. John’s wort
(D) Voriconazole
(E) Verapamil

tacrolimus blood concentrations
Cyclosporine (Neoral®) and tacrolimus (Prograf®) are potent immunosuppressive agents that have been shown to be effective in IBD. They are typically used for severe acute IBD as there is little data to support effi cacy in mild disease to off set the potential toxicities of these agents.

Mechanism of action. Both cyclosporine and tacrolimus are calcineurin inhibitors and are potent inhibitors of T-lymphocyte activation.

Dosing and administration.

Before therapy is initiated, patients should be screened for potential drug interactions, normal renal function, cholesterol levels, blood pressure, and electrolyte status to help avoid toxicity.

Cyclosporine is started IV at 2 to 4 mg/kg/day and titrated to levels of 250 to 350 ng/mL.
Tacrolimus is initiated at 0.1 to 0.15 mg/kg/day by month and titrated to trough concentrations of 10 to 15 ng/mL.
Patients who respond are discharged on oral drug. Oral cyclosporine is dosed at twice the IV dose divided b.i.d.
Azathioprine or 6-MP is added as soon as possible and oral systemic steroids are oft en given concomitantly also for 3 to 4 months.
Cyclosporine and tacrolimus are normally stopped at 3 to 4 months. A steroid taper is also started at 3 to 4 months and should be done over 4 to 8 weeks.