conazole on the pharmacokinetics and pharmacodynamics of midazolam was examined in a randomized, cross-over study in 12 volunteers. In the study, subjects ingested placebo or 400 mg fluconazole on Day 1 followed by 200 mg daily from Day 2 to Day 6. In addition, a 7.5 mg dose of midazolam was orally ingested on the first day, 0.05 mg/kg was administered intravenously on the fourth day, and 7.5 mg orally on the sixth day. Fluconazole reduced the clearance of IV midazolam by 51%. On the first day of dosing, fluconazole increased the midazolam AUC and Cmax by 259% and 150%, respectively. On the sixth day of dosing, fluconazole increased the midazolam AUC and Cmax by 259% and 74%, respectively. The psychomotor effects of midazolam were significantly increased after oral administration of midazolam but not significantly affected following intravenous midazolam.
A second randomized, double-dummy, placebo-controlled, cross over study in three phases was performed to determine the effect of route of administration of fluconazole on the interaction between fluconazole and midazolam. In each phase the subjects were given oral fluconazole 400 mg and intravenous saline; oral placebo and intravenous fluconazole 400 mg; and oral placebo and IV saline. An oral dose of 7.5 mg of midazolam was ingested after fluconazole/placebo. The AUC and Cmax of midazolam were significantly higher after oral than IV administration of fluconazole. Oral fluconazole increased the midazolam AUC and Cmax by 272% and 129%, respectively. IV fluconazole increased the midazolam AUC and Cmax by 244% and 79%, respectively. Both oral and IV fluconazole increased the pharmacodynamic effects of midazolam. (See PRECAUTIONS.)
Azithromycin
An open-label, randomized, three-way crossover study in 18 healthy subjects assessed the effect of a single 800 mg oral dose of fluconazole on the pharmacokinetics of a single 1200 mg oral dose of azithromycin as well as the effects of azithromycin on the pharmacokinetics of fluconazole. There was no significant pharmacokinetic interaction between fluconazole and azithromycin.
Microbiology
Mechanism of Action
Fluconazole is a highly selective inhibitor of fungal cytochrome P450 dependent enzyme lanosterol 14-α-demethylase. This enzyme functions to convert lanosterol to ergosterol. The subsequent loss of normal sterols correlates with the accumulation of 14-α-methyl sterols in fungi and may be responsible for the fungistatic activity of fluconazole. Mammalian cell demethylation is much less sensitive to fluconazole inhibition.
Activity In Vitro and In Clinical Infections
Fluconazole has been shown to be active against most strains of the following microorganisms both in vitro and in clinical infections.
Candida albicans
Candida glabrata (Many strains are intermediately susceptible)1
Candida parapsilosis
Candida tropicalis
Cryptococcus neoformans
The following in vitro data are available, but their clinical significance is unknown.
Fluconazole exhibits in vitro minimum inhibitory concentrations (MIC values) of 8 µg/mL or less against most (≥90%) strains of the following microorganisms, however, the safety and effectiveness of fluconazole in treating clinical infections due to these microorganisms have not been established in adequate and well-controlled trials.
Candida dubliniensis
Candida guilliermondii
Candida kefyr
Candida lusitaniae
