TACROLIMUS (FK-506) OVERDOSE - A REPORT OF 5 CASES

Introduction: Tacrolimus (FK 506), a potent anti-T cell agent, has bee n shown to be effective in preventing the rejection of transplanted or gans. Published research on tacrolimus has focused on effects associat ed with therapeutic use. virtually no literature addresses the acute t oxicity or the management of tacrolimus overdose. We report five cases of acute overdose with tacrolimus. Cafe Reports: A 2-year-old female with no prior medical history ingested 10 mg of tacrolimus. She remain ed asymptomatic. A 2-year-old female with a history of multiple viscer al organ transplants ingested 11 mg of her tacrolimus. She was admitte d to the hospital and activated charcoal was administered. Her renal f unction was monitored and no changes were noted in a 24 h period. She was discharged. A 29-year-old male renal transplant patient took 150 m g of tacrolimus. He recovered with only a minimal creatinine elevation . A 23-year-old heart and lung transplant patient ingested 375 mg of t acrolimus. She had no effects from the overdose. A 34-year-old female experienced an acute/chronic overdose of 7-9 mg and remained asymptoma tic. Discussion: Tacrolimus is a neutral macrolide antibiotic that is extracted from the fermentation broth of the soil fungus Streptomyces tsukubaensis. Chronic oral dosing has been associated with numerous si de effects. Although these patients ingested significant doses of tacr olimus, they suffered few toxic manifestations associated with tacroli mus. Conclusion: Little information is available regarding acute tacro limus overdosage. In this small series of patients, tacrolimus did not produce acute physiologic incapacitation.