Hepatotoxicity associated with the use of teriflunomide in a patient with multiple sclerosis: A case report.

Rationale: Teriflunomide is an inhibitor of pyrimidine synthesis available as a first-line treatment for relapsing-remitting multiple sclerosis. Drug-induced liver damage is a relevant problem in clinical practice, representing a frequent cause of treatment discontinuation. This case report describes the occurrence of liver injury, with a 33.7-fold increase in the upper limit of normality of the liver enzyme alanine aminotransferase during treatment with teriflunomide 14 mg.

Patient Concern: A 44-year-old woman receiving teriflunomide 14 mg for the treatment of multiple sclerosis presented symptoms suggestive of liver dysfunction 54 days after starting treatment. The patient had no history of using disease-modifying therapy, neither previous liver disease nor other comorbidities.

Diagnostics: The suggested diagnosis was drug-induced liver injury, classified as hepatocellular. Other possible hepatic and autoimmune etiologies were ruled out.

Interventions: Replacement of teriflunomide treatment with glatiramer acetate and follow-up of the disease.

Outcomes: Signs and symptoms regressed after treatment with teriflunomide 14 mg was discontinued, with normalization of liver enzyme activity in ∼5 months. The causality assessment of the adverse drug reaction was determined by the Naranjo scaling system, resulting in probable, with a final score of 7.

Conclusions: Teriflunomide-induced liver injury in patients with multiple sclerosis is a serious adverse reaction. The report of this case contributes to updating knowledge about the safety aspects of treatment with teriflunomide and planning of monitoring strategies and patient risk management.