Background and Importance Tofacitinib is a selective inhibitor of the Janus kinase family indicated for the treatment of various rheumatological pathologies such as rheumatoid arthritis (RA) and psoriatic arthritis. According to the technical data sheet (TDS), most frequently reported adverse effects (AE) during the first 3 months of clinical studies were headache, upper respiratory tract infections and viral respiratory tract infections upper. Pharmacovigilance collects information and analyses and notifies cases of suspected adverse drug reactions to prevent them occurring in the future.

Aim and Objectives Describe the causal relationship in a patient who suffers from erosive balanitis after the administration of tofacitinib, besides the multidisciplinary intervention in its management.

Material and Methods Retrospective and multidisciplinary study, which describes the case of a 66-year-old patient diagnosed with RA since 2007 and who, in 2019, after numerous failures with disease-modifying drugs (DMARDs), began treatment with tofacitinib 5 mg every 12 hours. Data were obtained from Diraya® digital medical record. Safety profile of tofacitinib was reviewed in its TDS and the Naranjo Algorithm was applied to establish the drug-adverse reaction causal relationship.

Results In January 2022, the patient was referred from primary care to the dermatology clinic due to erythema in glans area that had been developing for a month, reporting that he had an outbreak with the same characteristic’s previous year. Following this event, the precautionary suspension of tofacitinib was agreed with rheumatology team. Specialists contact the Hospital Pharmacy Service to confirm whether it is an AE secondary to tofacitinib. After this, the pharmacist performed a review of the TDS and literature confirming that there was no evidence of erosive balanitis as an AE of tofacinib. The suspected AE was reported to the Spanish Pharmacovigilance System and a causal relationship was established between the drug and the AE according to the Naranjo Algorithm, obtaining a score of 1 that established a possible relationship between the drug of interest and the AE. After topical cures for 2- months, treatment with tofacitinib was restarted in May 2022 without reporting new incidents.

Conclusion and Relevance Multidisciplinary participation in the detection, notification and actions, to establish the causal relationship of AE associated with drugs, contributes to improving patient safety.

Conflict of Interest No conflict of interest.