ANTIFUNGAL THERAPY: PAST, PRESENT, AND FUTURE
ANDREW HANZLICEK, DVM, MS, DACVIM MiraVista Diagnostics, Indianapolis, Indiana
In this VETgirl webinar entitled “Antifungal Therapy – Past, Present & Future,” Dr. Andrew Hanzlicek, DACVIM, provides a clinical review of antifungal treatment recommendations for common invasive fungal infections like blastomycosis, histoplasmosis, coccidioidiomycosis and more! Thanks to generous sponsorship from MiraVista Veterinary Diagnostics, you can view it HERE until April 21st FREE!
KEY HIGHLIGHTS
1 INTRODUCTION Invasive fungal infections (IFIs) are growing in importance in veterinary and human medicine. This is due to expanding endemic geographic ranges, emerging antifungal resistance, and increasing immunosuppressed populations. Invasive fungal infections are caused by enzootic dimorphic fungi (Blastomyces, Histoplasma, Coccidioides) , yeast (Cryptococcus and Candida) or molds. Aspergillus is a common pathogenic mold and opportunistic molds commonly fall into one of a few categories – hyalohyphomycosis, phaeohyphomycosis, zygomycosis, and eumycotic mycetoma. Amphotericin B is used for life- threatening IFIs and azoles are used for mild-to-moderate disease or following (step-down) amphotericin B therapy. These include first- generation drugs – itraconazole and fluconazole and second-generation drugs – posaconazole, voriconazole, and isavuconazole. Fluconazole and itraconazole are used most often in veterinary medicine and voriconazole and posaconazole are reserved for invasive molds or as salvage therapy when itraconazole or fluconazole treatment has failed. No data is available for isavuconazole in veterinary species.
Photo courtesy of Dr. Andrew Hanzlicek, MS, DACVIM
for fungal cell membrane integrity. Azoles cause lesser inhibition of mammalian metabolic CYP-450 enzymes, but enough to cause many potential drug-drug interactions (DDIs). Concurrent administration of an azole can significantly decrease metabolism, and thus increase blood concentrations of amitriptyline, amlodipine, benzodiazepines, cisapride, corticosteroids, cyclosporine, ivermectin, and macrolide antibiotics. Most azoles are metabolized by the liver and toxicity is more likely with decreased hepatic function. The primary adverse-effect of azoles is hepatoxicity and liver enzymes should be monitored during treatment. (continued)
When choosing an antifungal drug there are at least 5 important considerations: 1. Antifungal spectrum organism sensitivity to drug 2. Tissue penetration location of infection 3. Safety profile drug adverse-effects 4. Formulation route of administration 5. Cost of drug : affordability 2 AZOLE PHARMACOKINETICS AND ADVERSE-EFFECTS Azoles work by inhibiting a fungal CYP-450 enzyme, inhibiting the production of ergosterol, which is vital
12
vetgirlontherun.com
Made with FlippingBook - Online Brochure Maker