Clotrimazole is a broad-spectrum antifungal agent that inhibits the growth of pathogenic yeasts by altering the permeability of cell membranes. The action of clotrimazole is fungistatic at concentrations of drug up to 20 mcg/mL and may be fungicidal in vitro against Candida albicans and other species of the genus Candida at higher concentrations. No single-step or multiple-step resistance to clotrimazole has developed during successive passages of Candida albicans in the laboratory; however, individual organism tolerance has been observed during successive passages in the laboratory. Such in vitro tolerance has resolved once the organism has been removed from the antifungal environment.
After oral administration of a 10 mg clotrimazole troche to healthy volunteers, concentrations sufficient to inhibit most species of Candida persist in saliva for up to three hours following the approximately 30 minutes needed for a troche to dissolve. The long term persistence of drug in saliva appears to be related to the slow release of clotrimazole from the oral mucosa to which the drug is apparently bound. Repetitive dosing at three hour intervals maintains salivary levels above the minimum inhibitory concentrations of most strains of Candida; however, the relationship between in vitro susceptibility of pathogenic fungi to clotrimazole and prophylaxis or cure of infections in humans has not been established.
In another study, the mean serum concentrations were 4.98 ± 3.7 and 3.23 ± 1.4 nanograms/mL of clotrimazole at 30 and 60 minutes, respectively, after administration as a troche.