Parecoxib Rifampicin

NS AIDs RIFAMPICIN Rifampicin L diclofenac, celecoxib, etoricoxib and parecoxib levels Rifampicin T CYP2C9-mediated metabolism of these NSAIDs Monitor analgesic effects consider using alternative NSAIDs... 

Although information is limited, these pharmacokinetic interactions appear to be established. Their clinical relevance remains to be determine, but it seems likely that the efficacy of these NSAIDs will be reduced by rifampicin. Combined use should be well monitored, and the NSAID dosage increased if necessary. See also NSAIDs Parecoxib -i- Miscellane-ous%p.l60. The clinical relevance ofthe increase in rifampicin maximum levels with metamizole is uncertain. 

Enzyme inducers. The effects of the enzyme inducers carbamazepine, dexamethasone, phenytoin and rifampicin have not been studied with parecoxib. Nevertheless, the manufacturer of parecoxib warns that they may increase the metabolism of valdecoxib. ... 

As parecoxib is rapidly metabolised to valdecoxib, the interactions are usually considered to be due to the effects of valdecoxib. The manufacturer of parecoxib cautions the concurrent use with carbamazepine, dexamethasone and rifampicin as their effects on parecoxib have not been studied. Valdecoxib increases the levels of dextromethorphan and omeprazole. Because of these interactions, caution is advised with drugs that are metabolised by the same isoenzymes, nameiy flecainide, metoprolol, propafenone, omeprazoie, diazepam, imipramine and phenytoin. No interaction appears to occur between parecoxib and midazolam. 

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