diflucan cost (fluconazole) is a prescription medicine used to treat certain fungal infections of the mouth and throat, such as tinea versicolor (jock itch). You should not use Diflucan if you are allergic to it or similar medicines. It should be used only by the person taking it, at the lowest effective dose. Stop taking this medicine and get emergency medical help if signs of an allergic reaction occur with any of these symptoms: rash skin itching; hives; swelling of face, lips, tongue, or throat (severe); sneezing; trouble breathing or swallowing; face, lips, tongue or diflucan cost throat that are blistered, reddish