Repeated cholestyramine washouts in a pregnant patient on leflunomide: A case report

Abstract

Introduction: Leflunomide is a disease modifying antirheumatic drug (DMARD) that is commonly used for the treatment of rheumatoid arthritis (RA). It is considered as a category X drug because it is contraindicated during pregnancy (studies in pregnant women have demonstrated a risk to the fetus, and/or human or animal studies have shown fetal abnormalities; risks of the drug outweigh the potential benefits). In women attempting to conceive, it is necessary to ensure that leflunomide levels are undetectable in plasma to prevent the risk of fetal malformations. An 11-day treatment of cholestyramine has been shown to lower leflunomide active metabolite levels to near undetectable levels. Case Report: In this case report, we discuss an RA patient taking leflunomide, who had an unintended pregnancy requiring two treatment courses of cholestyramine for complete washout of leflunomide. A C-section was performed at 39 weeks and 3 days due to concerns about the fetus’ health and was complicated by postpartum hemorrhage. The infant received Apgar scores of 9 and 9 at 1 and 5 minutes. The infant was also found with no birth anomalies and was deemed healthy at a check-up of nine months of age. Conclusion: Although a single 11-day treatment is typically sufficient to safely lower the concentration of leflunomide, it is important to remeasure the leflunomide active metabolite levels after the treatment course of cholestyramine to ensure that levels have reached zero. When leflunomide levels remain significantly elevated, a second treatment course of cholestyramine is required, otherwise the fetus could potentially be exposed to its teratogenic properties.