Objective: To determine the effect of low-dose methotrexate in asthmatic patients on steroid use, asthma symptom scores, pulmonary function, airway reactivity, blood cellular components, and immunoglobulin E levels.
Design: A randomized, double-blind, parallel, placebo-controlled, 13-week clinical trial with follow-up of patients in an open trial of methotrexate at the conclusion of the double-blind study.
Setting: An asthma care outpatient clinic.
Patients: From February 1988 to March 1990, 19 patients with severe, steroid-dependent asthma were enrolled in the study. Two of these patients were excluded from analysis.
Interventions: Patients were administered methotrexate or placebo intramuscularly, to assure complete absorption, once weekly during the 13-week study.
Results: Patients on methotrexate and placebo both significantly decreased their steroid dose by 39.6% (95% CI, 25.1% to 54.1%, P = 0.001) and 40.2% (CI, 17.9% to 67.4%, P = 0.003), respectively. Pulmonary function did not differ significantly between the methotrexate and placebo groups. In addition, airway reactivity and symptom scores were unchanged on methotrexate or placebo. No significant toxicities were seen during the course of the 13-week blinded study, but one patient on methotrexate and prednisone in the follow-up period developed Pneumocystis carinii pneumonia and died. Despite continuing methotrexate for up to 1 year, and increasing methotrexate to 30 mg weekly, no significant benefit of methotrexate on asthma control could be shown.
Conclusion: Our study does not support the use of methotrexate in the treatment of severe asthma.