Diflucan is from a therapeutic class of drugs known as azole antifungals. Diflucan is used to treat serious fungal or yeast infections, such as vaginal infections and oropharyngeal candidiasis, or thrush of the mouth and throat. Diflucan is brand name drug that works by killing the fungus or yeast, or preventing its growth. Diflucan (fluconazole) is an antifungal medication which works by killing sensitive fungi by interfering with the formation of the fungal cell membrane. Diflucan is used to treat infections caused by a fungus which invades any part of the body such as mouth, throat, esophagus, lungs, genital area, the blood, and bladder. Diflucan is also used to prevent fungal infections especially in people who have a weak immune system caused by diseases such as AIDS or cancer treatment and bone marrow transplant. However, this medication may also be used for other conditions as determined by the doctor. Do not use this medication if you are allergic to any ingredient in it. Diflucan may cause some side effects including needed and unwanted. Some of them include; fever, diarrhea, dark urine, dizziness, cough, loss of appetite, chills or fast heartbeat.