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Pregnancy Risk

Contraindicated in Pregnancy

  • Pregnancy must be excluded prior to initiation of therapy with leflunomide.
  • Leflunomide is contraindicated in pregnant women, or women of childbearing potential who are not using reliable contraception.
  • Pregnancy must be avoided during and prior to completion of the drug elimination procedure after leflunomide treatment.


  • Severe liver injury, inculding fatal liver failure, has been reported in some patients treated with leflunomide.
  • Patients with pre-existing acute or chronic liver disease should not receive leflunomide.
  • Patients with elevated serum alanine aminotransferase (ALT) greater than two times the upper limit of normal before initiating treatment should not receive leflunomide.
  • Use caution when leflunomide is given with other potentially hepatotoxic drugs. 
  • Monitoring of ALT levels is recommended at least monthly for  6 months after starting leflunomide and thereafter every 6 to 8 weeeks. If the ALT rises to greater than 3 times the upper limit of normal while the patient is on leflunomide – leflunomide should be stopped while investigating the probable cause of the ALT elevation by close observation and additional tests.
  • If likely that ALT elevations are leflunomide-induced, start cholestryamine washout and monitor liver tests weekly until normalized.
  • If leflunomide-induved liver injury is unlikely because some other probable cause has been found, resumption of leflunomide therapy may be considered.


  • Exclude pregnancy prior to initiation of therapy
  • See product insert for specific instructions on patient counseling and testing

Patient Counseling Information

Package Inserts


Additional Information

Updated January 2018