Role of Ondansetron in Reducing Methotrexate Intolerance in Patients with Inflammatory Arthritis

To determine the frequency of intolerance to Methotrexate (MTX) in patients with inflammatory arthritis by using MTX intolerance severity score, and evaluate the effects of Ondansetron in reducing MTX intolerance.

Interventional study.

Rheumatology clinic, Combined Military Hospital (CMH), Lahore, from 1st November 2021 to 30th April 2022.

Patients with inflammatory arthritis taking methotrexate regularly for >3 months participated in the study. The patients' age, gender, education level, marital status and smoking history were documented. The disease duration and disease activity was also recorded. Dose/duration/route/frequency and timing of MTX were noted. MTX intolerance was calculated with the use of the Methotrexate intolerance severity score (MISS) questionnaire. Those MTX intolerant patients who reported nausea and vomiting were prescribed ondansetron along with MTX and were followed up for the next 3 consecutive months.

Out of 181 patients, 48(26.5%) showed methotrexate intolerance. The predominant symptom was nausea after taking MTX reported in 93.8% of the MTX intolerant patients followed by behavioural symptoms including restlessness and irritability reported among 79% and 77% of intolerant patients respectively. Those methotrexate intolerant patients who mainly had complaints of nausea and vomiting were started on ondansetron on the day of methotrexate and showed a significant reduction in the median of MISS score in the following two consecutive months (p <0.05) while at 3 months the median did not show further reduction as compared to second month (p=0.12).

Ondansetron prescribed along with methotrexate in patients having complaints of nausea and vomiting with MTX, reduces the intolerance significantly.

Rheumatoid arthritis, Methotrexate, Ondansetron, Nausea, Arthritis juvenile.