Tolbutamide Leflunomide

LEFLUNOMIDE ANTIDIABETIC DRUGS -TOLBUTAMIDE Possible T effect of tolbutamide Uncertain Monitor blood sugar closely. Watch for and warn patients about symptoms of hypoglycaemia - For signs and symptoms of hypoglycaemia, see Clinical Features of Some Adverse Drug Interactions, Hypoglycaemia... 

The serum levels of the active metabolite of leflunomide are reduced by activated charcoal, and colestyramine. The manufacturers advise against the concurrent use of alcohol because of the potential for hepatotoxicity. Methotrexate may also increase leflunomide hepatotoxicity, so in general the combination is not recommended. A case of fatal fulminant hepatic failure has been reported in a patient taking leflunomide and itraconazole. A case of peripheral neuropathy has been reported in a patient taking leflunomide and tegafiir/uraciL The manufacturers predict interactions between leflunomide and phenytoin or tolbutamide, and advise caution with rifampicin as it may increase leflunomide metabolite levels. No clinically relevant interaction occurs with cime-tidine, corticosteroids or NSAIDs. 

The manufacturers advise caution if leflunomide is given with phenytoin or tolbutamide. The reason is that the active metabolite of leflunomide (A771726) has been shown by in vitro studies to be an inhibitor of the cytochrome P450 isoenzyme CYP2C9, which is concerned with the metabolism of these two drugs. If this inhibition were to occur in vivo it could possibly lead to a decrease in their metabolism and an increase in their toxicity. Although so far there appear to be no clinical reports of an interaction, the manufacturers made a similar prediction with warfarin, another CYP2C9 substrate, which has, in isolated cases, been borne out in practice. See Coumarins + Leflunomide , p.423. 

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See also in sourсe #XX -- [ ]

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