TACROLIMUS 02

Tacrolimus in pregnancy and breastfeeding: Drug Safety Class: IMMUNOLOGIC AGENTS / Immunosuppressants References Fetal Fisk Summary Tacrolimus (FK506) is a macrolide immunosuppressant agent produced by Streptomyces tsukubaensis that acts similarly to cyclosporine but is a more potent immunosuppressant (1). It is used for the prophylaxis of organ rejection in patients receiving various allogeneic organ transplants, such as kidney, liver, heart, and pancreas. Reproduction studies have been reported in rats, rabbits, and mice (2,3). In pregnant rabbits, tacrolimus given in oral doses of 0.32 and 1.0 mg/kg (about 0.51 and 1.63.3 times, respectively, the recommended human dose based on body surface area [RHD]) during organogenesis was associated with maternal toxicity and an increased incidence of abortions (2). At the higher dose, an increased incidence of malformations and developmental variations was also observed (type of defects was not specified). Pregnant rats dosed with 3.2 mg/kg (2.34.6 times the RHD) exhibited maternal toxicity and an increase in late resorptions, decreased numbers of live births, and decreased pup weight and viability (2). Oral doses of 1.0 mg/kg (0.71.4 times the RHD) and 3.2 mg/kg given after organogenesis and during lactation were associated with reduced pup weight (2).