Yeast (Candida albicans) is a common type of fungus found on normal human skin, especially the moist surfaces like the mouth, the diaper are and the female vagina. When the amount of yeast increases in proportion to other normal bacteria of the skin due to some conditions like hormonal imbalance, a yeast infection is said to occur, and problematic symptoms like excessive itching arise. Learn more about yeast infection and the different drugs used to treat the disease.
What is Yeast Infection?
The abnormal proliferation of yeast (Candida albicans) in moist surfaces of the skin is technically known as Candidiasis, moniliasis or oidiomycosis. This type of infection usually occurs in superficial areas such as the vagina, the diaper area and the mouth but severely compromised individuals may also suffer from systemic or widespread infection that involves the blood.
Yeast infection may be classified according the area affected:
- Oral candidiasis – also known as thrush, affects the mucous membranes of the mouth of babies
- Oral candidosis or moniliasis – yeast infection that affects the mouth or throat of adults
- Candidal vulvovaginitis – yeast infection that affects the vulva and vagina
- Diaper Candidiasis – affects the moist areas usually covered by the diaper
- Perianal Candidiasis – affects the area around the anus
- Candidal paronychia – inflammation of the nail fold infected by yeast
- Angular cheilitis – also known as angular stomatitis, may be caused by fungal infection at the corners of the mouth, although this condition may also be brought about by other conditions like malnutrition
- Candidal intertrigo – found between intertriginous folds of skin, or areas where there is frequent skin-to-skin contact, such as the axilla and the skin between the breast
- Candidiasis of the skin, scalp,urinary tract, brain membranes, gastrointestinal system respiratory system and almost any other organ or system in the body
- Systemic Candidiasis – a disseminated type of infection, causing disease to the different systems of the body
Treatment for Yeast Infection
Candidiasis is effectively treated by antifungal medications known as antimycotics which may come in different preparations, depending on the areas being treated and the severity of infection. These preparations may be in the form or tablets, capsules, powder or suspensions that may be taken by mouth, intravenous injections, topical creams, vaginal suppositories and more. Common antifungal treatments that are known to work effectively include:
Azole Antifungal Drugs
This class of drugs has a broad-spectrum activity, and can be divided into two groups – the triazoles and the imidazoles. These drugs work by inhibiting cytochrome P450-dependent enzymes involved in the conversion and biosynthesis of ergosterol in the fungal cell membrane, resulting in leakage of the membrane that leads to the destruction and death of the cell.
Triazole antifungals include fluconazole, isavuconazole, itraconazole, voriconazole, pramiconazole, and posaconazole. Popular trade names currently being prescribed are Diflucan and Fluconazole (fluconazole), Sporanox (itraconazole), Vfend (voriconazole) and Noxafil (posaconazole).
Imidazole antifungals include ketoconazole (Nizoral), miconazole (Monistat) and clotrimazole (Gyne-Lotrimin and Mycelex-7).
Care should be taken with long term use of these drugs because of their potential to lead to life-threatening liver toxicity. Other concerns with the use of these drugs are the potential interaction with other drugs such as cyclosporin, certain antihistamines, anticoagulants, anticonvulsants, oral hypoglycemic drugs and other medications that are metabolized via similar pathways in the liver.
Polyene Antifungal Drugs
Amphotericin B (Amphotec), nystatin (Mycostatin), and pimaricin (Natamycin) are antifungal agents that interact with ergosterol in the cell membrane to form channels in the fungal cell membrane, resulting in the leakage of small molecule from the inside of the cell to the outside, ultimately leading to cell death.
Nystatin is the first antimycotic drug to be developed and is still being prescribed today for topical use.
Amphotericin B, discovered in 1956, is considered to be the gold standard of life-threatening types of yeast infections (except those affecting the skin) and must be administered intravenously. Serious side effects include renal toxicity.
Allylamine and Morpholine Antifungal Drugs
These drugs (naftifine, terbinafine) inhibit ergosterol biosynthesis and therefore interfere with cell membrane structure and function. They are marketed as Naftin and Lamisil, respectively. These are used for the treatment of yeast infection of the skin and nails.
Antimetabolite Antifungal Drugs
5-Fluorocytosine (Flucytocin) inhibits the synthesis of both DNA and RNA via the intracytoplasmic conversion of 5-fluorocytosine to 5-fluorouracil. Fluorouracil exerts its antifungal activity through subsequent conversion into several active metabolites which inhibit protein synthesis.
5-fluorocytosine is seldom used alone because of the emergence of drug resistance which is often encountered. It is therefore used in combination with amphotericin B to treat different types of fungal infection.
Other Antifungal Treatments
Griseofulvin (Fulvicin, Grisactin) is an antibiotic derived from Penicillium griseofulvum.It acts by inhibiting mitosis in fungal cells and is active against chronic fungal infections affecting the skin and nails.
Potassium iodide is the salt form of iodide, a naturally occurring substance. It is more commonly known for its use as an expectorant, an agent that thins mucus secretions from the respiratory system. It is also popularly used for thyroid protection. As an antifungal it is used orally to treat chronic cutaneous and lymphocutaneous sporotrichosis, an infection caused by the Sporothrix schenckii, a fungus found in vegetation such as rosebushes or briars, or in mulch-rich dirt.
Gentian violet or crystal violet is a type of dye used in pathological examinations like Gram’s staining method of classifying bacteria. Its medical use is related to its antibacterial, antifungal, and anthelmintic properties. It is commonly used to treat oral thrush.
Disclaimer: The information contained in this article is for educational purposes only and should not be used for diagnosis or to guide treatment without the opinion of a health professional. Any reader who is concerned about his or her health should contact a doctor for advice.
Dixon, Dennis M. and Walsh, Thomas (1996). Antifungal Agents. Medical Microbiology (Chap 76) Galveston, Tx: NCBI. http://www.ncbi.nlm.nih.gov/books/NBK8263/
Drugs.com, accessed 2/2/12