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
§ Inducers of drug clearance, such as
phenytoin, carbamazepine, efavirenz, nevirapine, and nelfinavir, may lower
§ 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.)