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Letter: oral low‐dose methotrexate for collagenous colitis

SIRS, We read with interest the recent paper by FernandezBanares et al. detailing evidence-based recommendations for the management of microscopic colitis. Included in this paper was an overview of the conflicting evidence relating to methotrexate treatment of collagenous colitis. We have recently analysed the outcome of a series of patients with collagenous colitis who were treated with oral methotrexate. We retrospectively studied 20 consecutive patients (19 females, median age 66 years) who had been diagnosed with biopsy-proven collagenous colitis in a single gastroenterologist’s practice between 1999 and 2013. Ten patients (all female, median age 62 years) were treated with oral methotrexate at an initial dose of 10 mg/week. Seven of these patients had previously been treated with loperamide, sulfasalazine or both without achieving clinical remission (defined as mean of <3 stools/day and mean <1 watery stool/day), and in the remaining three patients methotrexate was the first treatment commenced. All patients achieved clinical remission at first followup review. The median time to first review was 4 weeks post-methotrexate initiation (range 2–12 weeks). Histological remission of collagenous colitis was confirmed in the two patients who had repeat colonic biopsies while being treated with methotexate. No patients had a symptomatic relapse while continuing methotrexate therapy. No haematologic or hepatic toxicity was observed in any patient while being treated with methotrexate. As outlined by Fernandez-Banares, there are limited published data regarding methotrexate treatment of collagenous colitis. Riddell et al. described a retrospective case series and reported beneficial effects of oral low-dose methotrexate 5–25 mg/week in 16 of 19 (84%) patients with collagenous colitis. The median dose required to achieve clinical remission was 7.5 mg and the dose range was 5– 25 mg. Münch et al. reported the lack of efficacy and tolerability of subcutaneous methotrexate in the treatment of collagenous colitis, albeit in a group of patients who were previously budesonide refractory or intolerant. In this study, all nine of the treated patients failed to achieve clinical remission. Of note, the high dose of methotrexate used in this study (15–25 mg weekly) was associated with treatment limiting side effects which prevented four patients from completing the study, and the final dose of methotrexate (25 mg weekly) used in the remaining five patients is recognised to frequently cause gastrointestinal upset. It is possible that methotrexate-related gastrointestinal upset confounded the clinical assessment of disease response. Our data support the findings by Riddell et al. Within our group of 20 patients, low-dose oral methotrexate treatment achieved clinical remission quickly, and with good tolerability.