**4.5 Posaconazole**

Posaconazole is a new triazole, a synthetic structural analogue of itraconazole. It is available as an oral suspension (40 mg/ml), administered at a dose of 200 mg four times daily or 400 mg twice daily. Now also available as delayed release tablets (100 mg) and injection (18mg/ml). In vitro and in vivo studies showed that posaconazole has a broad spectrum against Candida spp., *Cryptococcus neoformans*, Aspergillus spp., and Fusarium spp. etc. and effective against most agents resistant to itraconazole and fluconazloe [87–91].

Evidence on its use in ocular infections is still limited, but initial results are encouraging. Sponsel et al. also describe a case of keratitis by *Fusarium solani* resistant to Amphotericin B and natamycin but successfully treated with topical drop (100 mg/ ml prepared from an oral solution) associated with oral posaconazole 200 mg 4 times daily [89]. However, comparative controlled studies with first-line antifungal agents are still lacking. Altun et al. reported successful treatment with posaconazole in two cases with recalcitrant fugal keratitis that were resistant to conventional antifungal drugs (systemic and topical fluconazole or voriconazole and amphotericin B and topical natamycin were all ineffective) [90]. Posaconazole use resulted in rapid resolution of infection in these cases without significant toxicity. Posaconazole can be useful in cases of fungal keratitis that are resistant to standard antifungal therapy. However,

the use of topical posaconazole as monotherapy needs to be evaluated as well as the optimum effective concentration has to be standardized. Two different concentration of the topical preparation is used in the above studies.
