Common side effects when applied to the skin include burning, itching, and a rash.[1] Common side effects when taken by mouth include vomiting and diarrhea.[1] During pregnancy use in the vagina is safe while other formulations have not been studied in this group.[1] It works by disrupting the cell membrane of the fungal cells.[1]
When given parenterally, its activity is reduced due to presence of plasma.[8]
Oral nystatin is often used as a preventive treatment in people who are at risk for fungal infections, such as AIDS patients with a low CD4+ count and people receiving chemotherapy. It has been investigated for use in patients after liver transplantation, but fluconazole was found to be much more effective for preventing colonization, invasive infection, and death.[9] It is effective in treating oral candidiasis in elderly people who wear dentures.[10]
It is also used in very low birth-weight (less than 1500 g or 3 lb 5oz o) infants to prevent invasive fungal infections, although fluconazole is the preferred treatment. It has been found to reduce the rate of invasive fungal infections and also reduce deaths when used in these babies.[11]
Liposomal nystatin is not commercially available, but investigational use has shown greater in vitro activity than colloidal formulations of amphotericin B, and demonstrated effectiveness against some amphotericin B-resistant forms of fungi.[12] It offers an intriguing possibility for difficult-to-treat systemic infections, such as invasive aspergillosis, or infections that demonstrate resistance to amphotericin B. Cryptococcus is also sensitive to nystatin. Additionally, liposomal nystatin appears to cause fewer cases of and less severe nephrotoxicity than observed with amphotericin B.[12]
Adverse effects
Bitter taste and nausea are more common than most other adverse effects.[7]
The oral suspension form produces a number of adverse effects including but not limited to:[13]
Too high of a dosage can potentially lead to additional side effects such as:[16]
Nephrotoxicity
Hypokalemia
Chills and skin rash
Mechanism of action
Like amphotericin B and natamycin, nystatin is an ionophore.[17] It binds to ergosterol, a major component of the fungal cell membrane. When present in sufficient concentrations, it forms pores in the membrane that lead to K+ leakage, acidification, and death of the fungus.[18] Ergosterol is a sterol unique to fungi, so the drug does not have such catastrophic effects on animals or plants. However, many of the systemic/toxic effects of nystatin in humans are attributable to its binding to mammalian sterols, namely cholesterol. This is the effect that accounts for the nephrotoxicity observed when high serum levels of nystatin are achieved.[16] Despite the molecular similarities and differences of ergosterol and cholesterol, there is currently no consensus as to why nystatin has a higher binding affinity for ergosterol because we don't understand how the nystatin pores are constructed.[19] Researchers have concluded thus far that nystatin pores are formed from 4-12 nystatin molecules, with an unknown number of the necessary sterol interactions.[20]
Nystatin also impacts cell membrane potential and transport by lipid peroxidation.[21]Conjugated double bonds in nystatin's structure steal electron density from ergosterol in fungal cell membranes. Lipid peroxidation alters the hydrophilicity of the interior of channels in the membrane, which is necessary to transport ions and polar molecules. Disruption of membrane transport from nystatin results in rapid cell death. Lipid peroxidation by nystatin also contributes significantly to K+ leakage due to structural modifications of the membrane.[22]
Biosynthesis
Nystatin A1 (often called nystatin) is biosynthesized by a bacterial strain, Streptomyces noursei.[23] The structure of this active compound is characterized as a polyene macrolide with a deoxysugar D-mycosamine, an aminoglycoside.[23] The genomic sequence of nystatin reveals the presence of the polyketide loading module (nysA), six polyketide syntheses modules (nysB, nysC, nysI, nysJ, and nysK) and two thioesterase modules (nysK and nysE).[23] It is evident that the biosynthesis of the macrolide functionality follows the polyketide synthase I pathway.[24]
Following the biosynthesis of the macrolide, the compound undergoes post-synthetic modifications, which are aided by the following enzymes: GDP-mannose dehydratase (nysIII), P450 monooxygenase (nysL and nysN), aminotransferase (nysDII), and glycosyltransferase (nysDI).[23] The biosynthetic pathway is thought to proceed as shown to yield nystatin.
Elizabeth Lee Hazen (left) and Rachel Fuller Brown in 1955.
Like many other antifungals and antibiotics, nystatin has bacterial origin. It was isolated from Streptomyces noursei in 1950 by Elizabeth Lee Hazen and Rachel Fuller Brown, who were doing research for the Division of Laboratories and Research of the New York State Department of Health. Hazen found a promising micro-organism in the soil of a friend's dairy farm. She named it Streptomyces noursei, after Jessie Nourse, the wife of the farm's owner.[26] Hazen and Brown named nystatin after the New York State Health Department in 1954.[27] The two discoverers patented the drug, and then donated the $13 million in profits to a foundation to fund similar research.[28]
Other uses
Penicillium-infected tangerine: The spot absent of growth had nystatin applied to it before the fungus covered the fruit.
In certain cases, a nystatin derivative has been used to prevent the spread of mold on objects such as works of art. For example, it was applied to wood panel paintings damaged as a result of the Arno River Flood of 1966 in Florence, Italy.[29]
Nystatin is also used as a tool by scientists performing "perforated" patch-clamp electrophysiological recordings of cells. When loaded in the recording pipette, it allows for measurement of electrical currents without washing out the intracellular contents, because it forms pores in the cell membrane that are permeable to only monovalentions,[30] preferably cations such as sodium, potassium, lithium, and cesium.[31]
This is a depiction of what a fusion event may look like when seen on a current measurement. There is a sudden jump in the current, followed by a slower recover as the current returns to its baseline measurement from before the fusion event. This fusion event would interrupt the stability of a nystatin pore.
Another electrophysiological measurement that can be made is fusion event duration in a nystatin-ergosterol based system. Fusions are measured while the voltage is held constant, and is characterized by a spike in the current that then returns to the baseline current as the nystatin channels close. When present in smaller concentrations, nystatin momentarily forms pores that allows a vesicle fusion to occur more easily; that fusion then interrupts the pore stability and the nystatin and ergosterol disperse from each other.[32] Conversely, researchers have found that the half-life of these nystatin pores increase with an increased dosage level of nystatin to the membrane systems. This indicates a lower energy of both the lipid membrane and the ionophores when there is a higher concentration of nystatin.[33]
Formulations
An oral suspension form is used for the prophylaxis or treatment of oropharyngeal thrush, a superficial candidal infection of the mouth and pharynx.
A tablet form is preferred for candidal infections in the intestines.
Nystatin is available as a topical cream and can be used for superficial candidal infections of the skin.
Additionally, a liposomal formulation of nystatin was investigated in the 1980s and into the early 21st century. The liposomal form was intended to resolve problems arising from the poor solubility of the parent molecule and the associated systemic toxicity of the free drug.
Nystatin pastilles have been shown to be more effective in treating oral candidiasis than nystatin suspensions.[10]
Due to its toxicity profile when high levels in the serum are obtained, no injectable formulations of this drug are currently on the US market. However, injectable formulations have been investigated in the past.[12]
^World Health Organization (2019). World Health Organization model list of essential medicines: 21st list 2019. Geneva: World Health Organization. hdl:10665/325771. WHO/MVP/EMP/IAU/2019.06.
^"Nystatin (Oral route)". Micromedex Detailed Drug Information. PubMed Health, U.S. National Library of Medicine. Archived from the original on 21 December 2013. Retrieved 1 April 2014.
^Stark G (July 1991). "The effect of ionizing radiation on lipid membranes". Biochimica et Biophysica Acta (BBA) - Reviews on Biomembranes. 1071 (2): 103–122. doi:10.1016/0304-4157(91)90020-w. PMID1854791.
^ abcdFjaervik E, Zotchev SB (June 2005). "Biosynthesis of the polyene macrolide antibiotic nystatin in Streptomyces noursei". Applied Microbiology and Biotechnology. 67 (4): 436–443. doi:10.1007/s00253-004-1802-4. PMID15700127. S2CID19291518.
^Dewick PM (2009). Medicinal Natural Products: A Biosynthetic Approach (3rd ed.). UK: John Wiley & Sons Ltd. ISBN978-0-471-97478-9.
^Elsner Z, Leszczyńska-Bakal H, Pawlak E, Smazyński T (1976). "Gel with nystatin for treatment of lung mycosis". Polish Journal of Pharmacology and Pharmacy. 28 (4): 349–352. PMID981024.
^Espinel-Ingroff A (2003). Medical mycology in the United States: a historical analysis (1894-1996). Springer. p. 62.
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