The antifungal medications clotrimazole and tolnaftate, available in several over-the-counter and prescription brands, both can treat athlete's foot and other fungal infections effectively under some circumstances. Sometimes strains of fungi develop resistance. Clotrimazole is used for vaginal and throat infections, while tolnaftate is only indicated for skin infections.
According to the Mayo Clinic, many different drug companies sell clotrimazole for vaginal or topical use over-the-counter under a variety of brand names. Tolnaftate, only sold as a topical preparation, also comes under a variety of brand names.
The Mayo Clinic website states that children up to 2 years of age should not use tolnaftate, but clotrimazole has been tested successfully in this population. Stores sell both clotrimazole and tolnaftate as topical preparations for fungal skin infections and clotrimazole for vaginal infections. According to MedlinePlus, physicians also prescribe clotrimazole lozenges for thrush, a fungal infection of the throat.
The fungi that cause athlete's foot or jock itch can develop resistance to antifungal medications like clotrimazole and tolnaftate, according to a study by Japanese researchers published in the journal "Arzneimittelforschung" in 1991.
Use antifungal medication for the full duration indicated, according to the American Osteopathic College of Dermatology. Ask a doctor for advice if a fungal infection does not clear up in that time.