Drug General Information (ID: DDIUMREBF4)
  Drug Name Leflunomide Drug Info Ipilimumab Drug Info
  Drug Type Small molecule Monoclonal antibody
  Therapeutic Class Antiinflammatory Agents Antineoplastics

 Mechanism of Leflunomide-Ipilimumab Interaction (Severity Level: Major)
     Increased risk of hepatotoxicity Click to Show/Hide Mechanism Graph
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      Drug Name Leflunomide Ipilimumab
      Mechanism Hepatotoxicity Hepatotoxicity
      Key Mechanism Factor 1
Factor Name Hepatotoxicity
Factor Description Combination of drugs that can induce hepatotoxicity may increase the risk of liver injury. Symptoms vary depending on the level of exposure and the total extent of liver damage, and may cause few symptoms if the damage is mild, and eventually lead to liver failure in patients with severe damage.
      Mechanism Description
  • Increased risk of hepatotoxicity by the combination of Leflunomide and Ipilimumab 

Recommended Action
      Management Caution is advised if leflunomide or teriflunomide must be used in patients who are currently receiving or have recently received treatment with other hepatotoxic agents (e.g., acetaminophen alcohol androgens and anabolic steroids antituberculous agents azole antifungal agents ACE inhibitors cyclosporine (high dosages) disulfiram endothelin receptor antagonists interferons ketolide and macrolide antibiotics kinase inhibitors minocycline nonsteroidal anti-inflammatory agents nucleoside reverse transcriptase inhibitors proteasome inhibitors retinoids thiazolidinediones tolvaptan vincristine zileuton anticonvulsants such as carbamazepine, hydantoins, felbamate, and valproic acid lipid-lowering medications such as fenofibrate, lomitapide, mipomersen, niacin, and statins herbals and nutritional supplements such as black cohosh, chaparral, comfrey, DHEA, kava, pennyroyal oil, and red yeast rice), and vice versa. Liver enzymes and bilirubin should be measured prior to initiation of leflunomide/teriflunomide therapy and at least monthly for the first six months of treatment and every 6 to 8 weeks thereafter. Patients with preexisting liver disease or elevated baseline liver enzymes (i.e., ALT greater than two times ULN) should not receive leflunomide or teriflunomide. Patients who develop elevated serum ALT greater than three times ULN while receiving these medications should discontinue treatment and be given washout procedures with cholestyramine or activated charcoal to accelerate elimination of leflunomide's active metabolite from plasma, which otherwise may take up to two years. Follow-up monitoring should be conducted at least weekly until the ALT value is within normal range, and washout procedures repeated as necessary. All patients treated with leflunomide or teriflunomide should be advised to seek medical attention if they experience potential signs and symptoms of hepatotoxicity such as fever, rash, itching, anorexia, nausea, vomiting, fatigue, malaise, right upper quadrant pain, dark urine, pale stools, and jaundice.

References
1 Canadian Pharmacists Association.
2 EMEA "EMEA public statement on leflunomide (ARAVA) - severe and serious hepatic reactions.".
3 Product Information. Arava (leflunomide). Hoechst Marion-Roussel Inc, Kansas City, MO.