Candida is a yeast, also classified as a fungus, that is commonly found on the skin, in the digestive tract and on the genitals of humans. In healthy individuals the yeast do not cause any harm; however, in those who have a suppressed immune system due to disease, medication, stress or diet, the yeast can overgrow causing a condition known as candidaisis. Candidiasis, which can range from a mild skin rash to a severe infection of the blood, can be treated with a variety of effective prescription drugs.
Nystatin is an oral anti-fungal medication available by a prescription. Nystatin kills yeast by binding to a specific compound, called ergosterol, found on yeast cell walls. Once bound, it causes the cell the leak, eventually causing its death.
Nystatin is often the first drug prescribed to treat an overgrowth of Candida in the intestines, according to the Environmental Illness Resource. Because nystatin is not absorbed through the intestines, it is not effective in treating Candida infections outside of the digestive tract. However, this also means that nystatin does not induce unwanted side effects.
Amphotericin B is an anti-fungal medication that has a structure very similar to nystatin. Oral amphotericin B is effective in treating intestinal Candida overgrowth and, because it is not absorbed into the blood stream, it does not induce unwanted side effects. Amphotericin B binds to the ergosterol on the cell wall of yeasts damaging it and causing potassium to leak resulting in death of the cell.
Amphotericin B can also be administered intravenously, allowing it to act systemically, meaning throughout the body. Administered this way, amphotericin B can cause a variety of side effects including fever, chills, confusion and anemia (low red blood cell level). However, because 90 percent of the medication is cleared from the blood within 12 hours, as reported by the Fungal Research Trust, the side effects can be managed with medications such as ibuprofen, acetaminophen or low dose opiates.
Fluconazole is a more recent anti-fungal medication, receiving approval from the Food and Drug Administration (FDA) in 1990. Fluconazole is a systemic anti-fungal, meaning that it is absorbed through the intestines after oral administration. It is also one of the safest anti-fungal medications, with a low incidence of side effects that may include nausea and abdominal discomfort.
Fluconazole is not without disadvantages. The cost of this medication is typically high and there is a 3 to 6 percent rate of drug resistance for Candida albicans, the most common yeast in humans according to statistics provided by The Fungal Research Trust. This means that the yeast are developing a resistance to this medication, rendering it useless in some cases.
Terbinafine HCL is the newest anti-fungal medication, approved by the FDA in 1992. Terbinafine is only available as an oral medication or a topical ointment. It is the most common drug prescribed to treat fungal infections of the nails, but is also useful in treating Candida infections. Terbinafine is readily absorbed in the body but is generally well tolerated cause only mild side effects of nausea, abdominal discomfort and skin allergies. There is also a lower incidence of Candida drug resistance to terbinafine than to other anti-fungal drugs such as fluconazole.