Drug Interaction Report

MONITOR: Because telbivudine is primarily eliminated by renal excretion, coadministration with drugs that affect renal function may alter the plasma concentrations of telbivudine and/or the coadministered drug.

MANAGEMENT: Caution is advised if telbivudine is prescribed in combination with potentially nephrotoxic drugs (e.g., aminoglycosides; polypeptide, glycopeptide, and polymyxin antibiotics; amphotericin B; adefovir; cidofovir; tenofovir; foscarnet; cisplatin; deferasirox; gallium nitrate; lithium; mesalamine; certain immunosuppressants; intravenous bisphosphonates; intravenous pentamidine; high intravenous dosages of methotrexate; high dosages and/or chronic use of nonsteroidal anti-inflammatory agents). Renal function should be evaluated prior to and during therapy with telbivudine. Adjustment of dosing interval is required in patients with renal insufficiency (creatinine clearance below 50 mL/min) at baseline or during treatment in accordance with the manufacturer's product labeling.

ADJUST DOSING INTERVAL: Consumption of food has led to a 27% decrease in the bioavailability of orally administered tacrolimus.

MANAGEMENT: Tacrolimus should be administered at least one hour before or two hours after meals.

GENERALLY AVOID: Grapefruit juice has been reported to increase tacrolimus trough concentrations. Data are limited, but inhibition of the CYP450 enzyme system appears to be involved.

MANAGEMENT: The clinician may want to recommend that the patient avoid ingesting large amounts of grapefruit juice while taking tacrolimus.