Rapid Induction Therapy with Oral Tacrolimus in Elderly Patients with Refractory Ulcerative Colitis Can Easily Lead to Elevated Tacrolimus Concentrations in Blood: A Report of 5 Cases

BACKGROUND Tacrolimus is reportedly effective for the treatment of refractory ulcerative colitis (UC). At our hospital, there has been an increase in the number of patients, including elderly patients, with refractory UC treated with tacrolimus. Here, we review the data from 5 patients with elderly-onset UC treated with tacrolimus as remission induction therapy. CASE REPORT The subjects were 5 patients ≥65 years of age with refractory UC who had received oral tacrolimus as remission induction therapy between 2009 and 2014 (3 men and 2 women; median age at onset, 75 years). At the start of the tacrolimus treatment, the median duration of disease was 3 months, and the type of UC was total colitis in 4 cases, and left-sided colitis in 1 case. The drugs used concomitantly at the start of tacrolimus treatment were mesalazine (5 cases) and an immunomodulator drug (1 case). Standard induction therapy (0.05 mg/kg/day) was used in 2 patients and rapid induction therapy (0.1 mg/kg/day) was used in the remaining 3 patients. One week after the start of treatment, the blood trough concentrations of tacrolimus were over the target level of 15 mg/mL in 4 patients. The clinical activity index values on day 0 and day 14 were 10.6±2.1 and 7.6±3.4, respectively. The ulcerative colitis endoscopic index of severity in the remaining 3 patients, after excluding the 2 patients who required colectomy within 14 days after the start of tacrolimus therapy, was 7.3±1.0 before the start of the tacrolimus treatment, improving to 4.5±0.5 on day 14. Subsequently, 1 of these 3 patients was also judged to need surgery due to symptom exacerbation, while complete remission was maintained in the other 2 patients. CONCLUSIONS In elderly-onset refractory UC patients, tacrolimus appears to be effective as remission induction therapy. However, since tacrolimus concentrations in the blood can rise easily in elderly patients, frequent monitoring of the drug concentrations and dosage adjustments are necessary.