Griseofulvin is not useful in one of the following :
**Core Concept**
Griseofulvin is an antifungal medication used to treat fungal infections of the skin, hair, and nails. It works by inhibiting fungal cell division and mitosis, ultimately leading to the death of fungal cells.
**Why the Correct Answer is Right**
Griseofulvin is not effective against yeast infections, as it only targets fungi with a cell wall made of chitin. It is particularly useful in treating dermatophyte infections such as ringworm, tinea corporis, and onychomycosis. Griseofulvin binds to keratin in the fungal cell wall, disrupting its structure and preventing fungal growth.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect as griseofulvin is effective against dermatophytes, which include fungi such as Trichophyton, Microsporum, and Epidermophyton.
* **Option B:** This option is incorrect as griseofulvin is used to treat fungal infections of the skin, hair, and nails, including tinea capitis and onychomycosis.
* **Option C:** This option is incorrect as griseofulvin is not used to treat candidiasis, a yeast infection caused by Candida species.
**Clinical Pearl / High-Yield Fact**
Griseofulvin should not be taken with antacids or bile acid sequestrants, as these can reduce its absorption. Additionally, griseofulvin is contraindicated in patients with porphyria, as it can exacerbate the condition.
**Correct Answer:** C.