Ravuconazole belongs to a group of ‘‘second generation’’ triazoles; developed to overcome limitations, drug resistance, and drug interactions of the earlier triazoles. Formerly BMS-207147 and ER-30346, it was discovered by Eisai Co. Ltd. in Japan, developed by Bristol-Myers Squibb, and is now held again by Eisai. It is structurally related to fluconazole and voriconazole but, like isavuconazole, has a long half-life.
Ergosterol biosynthesis inhibitor. Antifungal.
The primary mode of action of ravuconazole is by inhibition of cytochrome P450 14a-demethylase, an enzyme in the sterol biosynthesis pathway. It is most potent against Candida spp. but has a broader spectrum of activity than fluconazole and itraconazole. It also has activity against Cryptococcus neoformans, Aspergillus fumigatus, dermatophytes, and dematiaceous fungi with limited activity against Sporothrix schenckii, Pseudallescheria boydii, Scedosporium apiospermum, Fusarium spp., and Zygomycetes. It is currently undergoing phase II clinical trials.
In animal models, the oral bioavailability of ravuconazole ranged from 48% to 74%. The presence of food enhanced absorption, with a 2- to 4-fold increase in bioavailability when administered with a high-fat meal. Ravuconazole had a long serum elimination half-life ranging from 3.9 to 202 hours. Protein binding was high at 95.8% to 98%.
As with the other azoles, ravuconazole inhibits the P450-dependent enzyme lanosterol 14-a demethylase, resulting in depletion of ergosterol and the accumulation of 14-a demethylated precursors. This interferes with the function of ergosterol in fungal membranes and breaks down the integrity of the membranes.
For doses o2.5 mg/kg/day in human volunteers, there has been
minimal hepatotoxicity and nephrotoxicity. Headache and abdominal
pain were most frequently reported, followed by diarrhea, pruritus, and
rash. No side-effects have been
noted in rats and dogs treated with ravuconazole for a week.
There are still ongoing clinical trials assessing the tolerability of this
drug in both the oral and parenteral formulations.
Ravuconazole may have a lower potential for drug interactions as it is a
less-potent inhibitor of CYP3A4 than voriconazole; however, no
information is available about interaction with other liver cytochrome
enzymes such as CYP2C9 or 2C19. One
clinical trial of ravuconazole in subjects with oral candidiasis and HIV
found that rifampicin reduced ravuconazole levels by over 50%.
