Glucan synthesis inhibitors
Caspofungin is a drug in a new class of agents known as glucan synthesis inhibitors (also called echinocandins). Its major use isin the patient who hasn’t responded to other antifungal therapies, such as amphotericin B or itraconazole.
After being given intravenously, caspofungin is highly protein-bound, with little distribution into RBCs. The drug is slowly me-tabolized and is excreted in urine and stool.
Caspofungin inhibits the synthesis of beta (1,3) D-glucan, an inte-gral component of the fungal cell wall.
Caspofungin is used to treat invasive aspergillosis in the patient who hasn’t responded to, or can’t tolerate, other antifungals. It hasn’t been studied as an initial treatment for invasive aspergillo-sis.
§ Patients taking caspofungin and tacrolimus may need higher doses of tacrolimus because caspofungin decreases the blood tacrolimus level.
§ Inducers of drug clearance, such as phenytoin, carbamazepine, efavirenz, nevirapine, and nelfinavir, may lower caspofungin clear-ance.
§ Concurrent use of caspofungin and cyclosporine may result in elevated liver enzyme levels and decreased caspofungin clear-ance, so use together isn’t recommended. (See Adverse reactionsto caspofungin.)