I know it's long, but I just Wikipedia-ed it. Hope it helps!
Ketoconazole (pronounced /ˌkiːtɵˈkoʊnəzɒl/) is a synthetic antifungal drug used to prevent and treat skin and fungal infections, especially in immunocompromised patients such as those with AIDS or those on chemotherapy. Ketoconazole is sold commercially as an anti-dandruff shampoo, topical cream, and oral tablet, under the trademark name Nizoral by Johnson & Johnson in the USA & Australia, and as Sebizole by Douglas Pharmaceuticals in Australia & New Zealand. In Spain products with ketoconazole as main agent include Ketoisdin gel 2% (gel) and Fungarest (topical 30 g cream).
Ketoconazole is very lipophilic, which leads to accumulation in fatty tissues. The less toxic and more effective triazole compounds fluconazole and itraconazole have largely replaced ketoconazole for internal use. Ketoconazole is best absorbed at highly acidic levels, so antacids or other causes of decreased stomach acid levels will lower the drug's absorption when taken orally. Absorption can be increased by taking it with an acidic beverage, such as cola.
Ketoconazole is usually prescribed for topical infections such as athlete's foot, ringworm, candidiasis (yeast infection or thrush), and jock itch. The over-the-counter shampoo version can also be used as a body wash for the treatment of tinea versicolor.
Ketoconazole is used to treat eumycetoma, the fungal form of mycetoma.
The side-effects of ketoconazole are sometimes used to treat non-fungal problems. The decrease in testosterone caused by the drug makes it useful for treating prostate cancer and for preventing post-operative erections following penile surgery. Another use is the suppression of glucocorticoid synthesis, where it is used in the treatment of Cushing's disease. These side effects have also been studied for use in reducing depressive symptoms and drug addiction; however, it has not succeeded in either of these roles.
Ketoconazole can be prescribed as a 200 mg pill, a 2% cream, a 2% gel,a 2% foam,or 2% shampoo for the treatment of dandruff or seborrhoeic dermatitis, or as a 1% over-the-counter shampoo (Perkhotal) & (Nizoral). However, 2% shampoo is sold over-the-counter in many countries as well.
Ketoconazole is also available as a topical mousse marketed under the brand name Ketomousse. In clinical studies, this preparation proved to be a superior mechanism of delivery to the shampoo. Currently it is only available in Europe.
Ketoconazole is also used in combination with other drugs such as zinc pyrithione in rinse-off products.
The anti-dandruff shampoo is designed for people who have a more serious case of dandruff where symptoms include, but are not limited to constant non-stop flaking, and severe itchiness.
It is a pregnancy category C drug because animal testing has shown it to cause teratogenesis in high dosages. Until recently, there were two human test cases on record (both during the treatment of Cushing's syndrome) and no adverse effects were reported, but this is not a broad enough data sample to draw any meaningful conclusions. A subsequent trial in Europe failed to show a risk to infants of mothers receiving ketoconazole.
This medication is also sometimes prescribed by veterinarians for use on pets, often as 200 mg unflavored tablets that may need to be cut to smaller size for correct dosage.
I thought I had a yeast infection and I thought it was razor burn. My physician prescribed me some cream called Ketoconazole Cream 2% and it helped tremendously.