Rifampicin Caspofungin

RIFAMPICIN CASPOFUNGIN 1 caspofungin levels, with risk of therapeutic failure Induction of caspofungin metabolism T dose of caspofungin to 70 mg daily... 

Rifampicin modestly reduces the trough levels of caspofungin after 2 weeks of concurrent use, but this is not thought to be due to increased metabolism. One case of caspofungin treatment failure has been reported in a patient taking rifampicin. Other enzyme inducers (carbamazepine, dexamethasone, efavirenz, nevirapine, and phenytoin) also appeared to reduce caspofungin levels. Rifampicin and other unnamed enzyme inducers did not appear to alter anidulafungin clearance. 

Caspofungin is a poor substrate for cytochrome P450 and is not a substrate for P-glycoprotein, therefore these mechanisms are not thought to be involved in the interaction with rifampicin. It is possible that the modest effect of rifampicin on caspofungin is due to induction of tissue uptake transport proteins at steady-state. ... 

The manufacturers recommend that consideration should be given to increasing the dose of caspofungin from 50 to 70 mg daily in patients taking rifampicin. - This dose has been generally well tolerated in clinical studies. . However, bear in mind the case report of possible caspofungin failure, even at this dose. The manufacturers also say that a population pharmacokinetic analysis suggested that the concurrent use of other met-... 

Bebnares J, Colaizzi L, Parada JP, Johnson S. Caspofungin treatment iluie in a patient with invasive candidiasis and concomitant rifampicin treatment. IrtJAntmdcrcb Agents (2005) 26, 264-5. 

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