While herpes zoster (HZ) has been linked to JAK inhibitors such as tofacitinib, it is unclear whether concomitant methotrexate (MTX) and/or glucocorticoids increase this risk. In a recent American study, HZ risk has been assessed in tofacitinib-treated rheumatoid arthritis patients with and without concomitant MTX and glucocorticoids. Of 8,030 new tofacitinib patients (mean ± SD age: 60.3 ± 12.6 years), prevalence of HZ was lowest when glucocorticoids were absent (3.4 per 100 patient-years with MTX; 3.7 per 100 patient-years without MTX). Prevalence of HZ increased approximately 2-fold for patients receiving either glucocorticoids (6.0 per 100 patient-years) or both MTX and glucocorticoids (6.5 per 100 patient-years). The adjusted hazard ratio for HZ in tofacitinib users given MTX and glucocorticoids was 1.96 (95% CI 1.33-2.88), but no significant increased risk was found for those treated only with MTX. It was also stated that older age and being female contributed to risk, while zoster vaccination may decrease risk. The study, which can be viewed here, concludes that the HZ incidence of 4% per year was doubled with glucocorticoid exposure, but the risk was not increased with concomitant MTX.

Contributed by Australian Medication Safety Services Associate – Isabella Singh