For systemic mycosis fluconazole is preferred over ketoconazole because of -

Ans. is 'd' i.e., All the above Imidazoles and Triazoles* These are presently the most extensively used antifungal drugs.* Four imidazoles are entirely topical, while ketoconazole is used both orally and topically.* Two triazoles fluconazole and itraconazole have largely replaced ketoconazole for systemic mycosis because of greater efficacy, Longer 11/2, fewer side effects and drug interactions.* The imidazoles and triazoles have broad spectrum antifungal activity covering dermatophytes, Candida, other fungi involved in deep mycosis (except mucor), Nocardia, some gram positive and anaerobic bacteria, e.g.* Staph, aureus, Strep, faecalis, Bac. fragilis and Leishmania.* The mechanism of action of imidazoles and triazoles is the same. They inhibit the fungal cytochrome P450 enzyme Tanosterol 14-demethylase' and thus impair ergosterol synthesis leading to a cascade of membrane abnormalities in the fungus.* The lower host toxicity of triazoles compared to imidazoles has correlated with their lower affinity for mammalian CYP450 enzymes and lesser propensity to inhibit mammalian sterol synthesis.* However, because they are active against certain bacteria as well (which do not have ergosterol), other mechanisms of action also appear to be involved.