Griseofulvin is not useful in one of the following:(1990)
**Core Concept**
Griseofulvin is an antifungal medication primarily used to treat fungal infections of the skin, hair, and nails. It works by inhibiting the synthesis of fungal cell walls, specifically by binding to the enzyme microtubule polymerization, thereby disrupting fungal cell division.
**Why the Correct Answer is Right**
Griseofulvin is not effective against fungal infections caused by yeasts, such as Candida species. This is because griseofulvin is lipophilic and only penetrates keratinized tissues, whereas yeasts do not infect keratinized tissues. Additionally, griseofulvin is not absorbed orally and requires microsomal P450 enzyme for its activation, which is not present in the gastrointestinal tract.
**Why Each Wrong Option is Incorrect**
**Option A:** Griseofulvin is not useful against dermatophytes.
* This is incorrect because griseofulvin is actually effective against dermatophytes, such as Trichophyton, Microsporum, and Epidermophyton species.
**Option B:** Griseofulvin is not useful against Candida species.
* This is correct because griseofulvin is not effective against fungal infections caused by yeasts, such as Candida species.
**Option C:** Griseofulvin is not useful in the treatment of tinea versicolor.
* This is incorrect because tinea versicolor is caused by Malassezia, a yeast-like fungus, but griseofulvin can be used for the treatment of Malassezia infections.
**Option D:** Griseofulvin is not useful against Aspergillus species.
* This is incorrect because griseofulvin can be used to treat Aspergillus infections.
**Clinical Pearl / High-Yield Fact**
Griseofulvin should be taken with a high-fat meal to enhance its absorption, and it should not be taken with antacids or antifungal medications that can decrease its absorption.
**Correct Answer: B. Griseofulvin is not useful against Candida species.**