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Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice.
Polyene Antifungal [EPC]
Nystatin is a potent polyene antifungal medication used to treat various fungal infections, particularly those caused by Candida species. It is available in multiple forms including oral suspensions, tablets, and topical applications.
Name
Nystatin
Raw Name
NYSTATIN
Category
Polyene Antifungal [EPC]
Drug Count
12
Variant Count
129
Last Verified
February 17, 2026
RxCUI
1053697, 543546, 884308, 1053753, 646456, 312055, 312059, 261178, 584414
UNII
BDF1O1C72E, F446C597KA
About Nystatin
Nystatin is a potent polyene antifungal medication used to treat various fungal infections, particularly those caused by Candida species. It is available in multiple forms including oral suspensions, tablets, and topical applications.
Detailed information about Nystatin
This page is for informational purposes only and does not replace medical advice. Consult a qualified healthcare professional before using any medication containing Nystatin.
Unlike many other antifungal agents, Nystatin is unique because it is virtually non-absorbed from the gastrointestinal tract, skin, or mucous membranes. This property makes it exceptionally useful for treating infections of the mouth (oral thrush), the intestinal tract, and the skin without causing the systemic toxicity often associated with other polyene antifungals like Amphotericin B. Because it does not enter the bloodstream in significant amounts, it is often referred to as a 'topical' agent, even when taken orally as a suspension or tablet for intestinal use.
At the molecular level, Nystatin exerts its antifungal activity by exploiting the differences between fungal and mammalian cell membranes. The primary target of Nystatin is ergosterol, a sterol molecule that is an essential component of the fungal cell membrane, serving a similar role to cholesterol in human cells.
When Nystatin is administered, the polyene molecules bind with high affinity to the ergosterol molecules within the fungal cell wall. This binding triggers the formation of transmembrane pores or channels. These pores disrupt the physical integrity of the membrane, leading to a rapid increase in membrane permeability. Consequently, vital intracellular components—most notably potassium ions (K+), sugars, and proteins—leak out of the fungal cell. This massive efflux of essential nutrients and electrolytes collapses the electrochemical gradient of the cell, leading to fungal cell death (fungicidal effect) or the inhibition of growth (fungistatic effect), depending on the concentration of the drug and the sensitivity of the fungal species.
Because human cell membranes contain cholesterol rather than ergosterol, Nystatin has a much lower affinity for human cells, which accounts for its relatively low toxicity profile when applied locally or taken orally.
Understanding the pharmacokinetics of Nystatin is crucial for its effective clinical application, as its behavior in the body is highly atypical compared to systemic drugs.
Nystatin is indicated for the treatment of various infections caused by Candida albicans and other susceptible Candida species. Its primary FDA-approved indications include:
Off-label, healthcare providers may occasionally use Nystatin as a prophylactic (preventative) measure in patients with severely weakened immune systems to prevent the overgrowth of yeast during antibiotic therapy.
Nystatin is available in a variety of formulations to target specific sites of infection:
> Important: Only your healthcare provider can determine if Nystatin is right for your specific condition. The choice of formulation depends entirely on the location and severity of the fungal infection.
The dosage of Nystatin is measured in 'Units' rather than milligrams, which is standard for many antibiotic and antifungal substances derived from biological sources.
Nystatin is widely used in pediatric populations, particularly for neonatal thrush.
Because Nystatin is not absorbed into the systemic circulation and is excreted in the feces, dosage adjustments are generally not required for patients with kidney disease or renal impairment.
There are no specific dosage adjustments recommended for patients with liver disease, as Nystatin does not undergo hepatic metabolism.
No specific age-related dosage adjustments are required for geriatric patients, though healthcare providers should monitor for the patient's ability to properly administer the oral suspension (swishing) if they have cognitive or physical limitations.
Proper administration is critical to the success of Nystatin therapy:
If you miss a dose of Nystatin, take it as soon as you remember. However, if it is almost time for your next scheduled dose, skip the missed dose and return to your regular dosing schedule. Do not double the dose to catch up.
Because Nystatin is not absorbed systemically, an overdose from topical or oral use is unlikely to cause life-threatening symptoms. However, very large oral doses may cause significant gastrointestinal upset, including nausea, vomiting, and diarrhea. In the event of an accidental ingestion of a large quantity by a child, contact a poison control center or seek emergency medical attention immediately.
> Important: Follow your healthcare provider's dosing instructions precisely. Do not adjust your dose or stop the medication without first consulting your medical professional.
Nystatin is generally very well tolerated because it stays localized to the site of application. However, some patients may experience mild side effects:
While Nystatin is safe for most people, serious reactions can occur.
> Warning: Stop taking Nystatin and call your doctor immediately if you experience any of the following:
Because Nystatin is not absorbed into the bloodstream, it does not typically cause the long-term systemic side effects associated with other drugs (such as kidney damage or bone density loss). The primary risk of long-term use is the potential for the development of Nystatin-resistant fungi, although resistance to Nystatin is much less common than resistance to 'azole' antifungals (like fluconazole). Prolonged topical use may also lead to skin thinning or sensitization to the ingredients in the cream base.
No FDA black box warnings have been issued for Nystatin. It is considered a safe medication when used as directed for localized fungal infections. However, it is explicitly stated in the clinical literature that Nystatin should NOT be used for the treatment of systemic mycoses (fungal infections of the blood or internal organs), as it is ineffective for these conditions.
Report any unusual symptoms or persistent side effects to your healthcare provider to ensure your treatment plan remains safe and effective.
Nystatin is specifically designed for the treatment of localized Candida infections. It is not effective against other types of infections, such as those caused by bacteria or viruses. Using Nystatin for non-fungal infections can lead to a delay in proper treatment and may contribute to the development of drug-resistant organisms.
Patients should be aware that Nystatin is not intended for systemic use. It cannot treat fungal infections that have spread to the blood, lungs, or other internal organs. If you have symptoms of a systemic infection, such as high fever, chills, or severe malaise, you must seek immediate medical evaluation for systemic antifungal therapy.
There are currently no FDA black box warnings for Nystatin. It has a long-standing safety record when used appropriately for its indicated purposes.
For most patients, routine laboratory monitoring (such as blood counts or liver function tests) is not required while using Nystatin because of its lack of systemic absorption. However, healthcare providers will monitor the clinical progress of the infection. If the infection does not improve within 7 to 14 days of treatment, further diagnostic testing (such as a fungal culture) may be necessary to confirm the identity of the pathogen and its sensitivity to Nystatin.
Nystatin does not cross the blood-brain barrier and does not cause drowsiness, dizziness, or cognitive impairment. Therefore, it is generally considered safe to drive or operate heavy machinery while using this medication.
There are no known direct interactions between Nystatin and alcohol. However, patients with oral thrush should avoid alcohol, as it can irritate the sensitive mucous membranes of the mouth and may interfere with the healing process. Additionally, excessive alcohol consumption can weaken the immune system, making it harder for the body to clear the fungal infection.
Nystatin does not require a tapering period. It can be stopped once the full prescribed course is completed. There is no risk of withdrawal syndrome. However, stopping the medication prematurely significantly increases the risk of the infection returning, potentially in a more resistant form.
> Important: Discuss all your medical conditions, including any history of allergies or diabetes, with your healthcare provider before starting Nystatin.
Due to the lack of systemic absorption of Nystatin, there are no documented 'contraindicated' drug-drug interactions where the combination is strictly prohibited for safety reasons. However, Nystatin should not be used concurrently with other oral or topical medications at the same site of application if they physically interfere with Nystatin's ability to coat the infected area.
Nystatin does not typically interfere with standard blood or urine laboratory tests. However, if a patient is undergoing a fungal culture, the presence of Nystatin in the sample will inhibit the growth of the fungi, potentially leading to a false-negative result. The healthcare provider should be informed of Nystatin use before any cultures are taken.
For each interaction, the primary management strategy is either spacing the doses (in the case of probiotics) or ensuring the physical application of Nystatin is not disturbed by other substances. Because the drug is not metabolized by the liver, the complex 'CYP inhibition' interactions common with other drugs are not a concern here.
> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking, even those applied to the skin.
There is only one primary absolute contraindication for the use of Nystatin:
Relative contraindications are conditions where the drug should be used with caution and only if the benefits outweigh the risks:
There is a theoretical risk of cross-sensitivity between Nystatin and other polyene antifungals, such as Amphotericin B or Natamycin. If a patient has had a severe reaction to one polyene antifungal, healthcare providers will exercise extreme caution when prescribing another drug in the same class, although the risk is considered low due to the localized nature of Nystatin.
> Important: Your healthcare provider will evaluate your complete medical history, including any previous drug allergies, before prescribing Nystatin to ensure it is the safest option for you.
Nystatin is classified by the FDA as Pregnancy Category C. This means that animal reproduction studies have not been conducted, and there are no adequate and well-controlled studies in pregnant women. However, because Nystatin is not absorbed systemically from the GI tract or intact skin, the risk to the developing fetus is considered extremely low. Most clinical guidelines suggest that Nystatin can be used during pregnancy for the treatment of oral or vaginal candidiasis if the healthcare provider deems it necessary. It is generally preferred over systemic antifungals (like oral fluconazole) during the first trimester.
It is not known whether Nystatin is excreted in human milk. However, since the drug is not absorbed into the mother's bloodstream, it is highly unlikely that any significant amount would reach the breast milk. Nystatin is often used directly to treat thrush in nursing infants, further suggesting a high safety margin. Nursing mothers should ensure that Nystatin cream applied to the breast area for skin infections is thoroughly cleaned off before breastfeeding to prevent the infant from ingesting the cream base.
Nystatin is FDA-approved and commonly used in pediatric patients, including neonates. It is the first-line treatment for 'diaper rash' caused by Candida and for neonatal oral thrush. The safety and effectiveness have been well-established in this population. The main consideration in children is the proper administration of the oral suspension; parents must ensure the liquid is distributed throughout the mouth as instructed.
Clinical studies of Nystatin did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. However, clinical experience has not identified differences in responses between the elderly and younger patients. One concern in the geriatric population is the high sugar content in oral suspensions for patients with age-related glucose intolerance or diabetes. Additionally, elderly patients with dentures must be instructed to clean their dentures thoroughly, as yeast can colonize the denture material and cause reinfection.
No dosage adjustments are necessary for patients with renal impairment. Since Nystatin is not absorbed and is eliminated via the feces, the kidneys do not play a role in its clearance. Even patients on hemodialysis can safely use Nystatin at standard doses.
Similarly, hepatic impairment does not affect the pharmacokinetics of Nystatin. It is not metabolized by the liver, so patients with cirrhosis or other liver diseases do not require dose modifications.
> Important: Special populations require individualized medical assessment. Always inform your doctor about your pregnancy status or any chronic health conditions.
Nystatin is a polyene antifungal antibiotic. Its molecular structure consists of a large macrolide ring with several conjugated double bonds on one side and multiple hydroxyl groups on the other, making the molecule amphipathic (having both water-loving and fat-loving parts).
The mechanism of action involves a physical interaction with the fungal cell membrane. Nystatin molecules orient themselves within the membrane by binding specifically to ergosterol. This binding causes the Nystatin molecules to aggregate and form a barrel-like pore that spans the membrane. These pores allow for the uncontrolled leakage of intracellular cations (like K+) and other small molecules. The loss of these components disrupts cellular metabolism and leads to cell lysis. Because human cells contain cholesterol instead of ergosterol, and because the geometry of the Nystatin-ergosterol complex is unique, the drug is selectively toxic to fungi.
Nystatin is primarily fungicidal (kills fungi) against a wide variety of yeasts and yeast-like fungi. The onset of action is relatively rapid upon contact with the fungal cells, but clinical improvement of symptoms (like the disappearance of white patches in thrush) usually takes 24 to 72 hours. The duration of effect is limited to the time the drug remains in physical contact with the infected tissue. Resistance to Nystatin is rare in Candida albicans but has been noted in other Candida species after prolonged exposure.
| Parameter | Value |
|---|---|
| Bioavailability | < 5% (Negligible) |
| Protein Binding | N/A (Not absorbed) |
| Half-life | N/A (Not absorbed) |
| Tmax | N/A (Local action) |
| Metabolism | None (Not hepatic) |
| Excretion | Fecal (approx. 100% unchanged) |
Nystatin is classified as a Polyene Antifungal. It is in the same therapeutic class as Amphotericin B and Natamycin. Unlike Amphotericin B, which can be administered intravenously for systemic infections, Nystatin's use is strictly limited to topical and gastrointestinal applications due to its high toxicity if it were to enter the bloodstream directly.
Medications containing this ingredient
Common questions about Nystatin
Nystatin is primarily used to treat fungal infections caused by yeast, specifically those in the Candida family. Its most common application is for oral candidiasis, also known as thrush, which presents as white patches in the mouth and throat. It is also frequently prescribed for intestinal yeast infections and skin infections like diaper rash or fungal growth in skin folds. Because it is not absorbed into the blood, it is excellent for localized treatment. Your healthcare provider will determine the specific form—liquid, tablet, or cream—based on where your infection is located.
The most common side effects of Nystatin are generally mild and localized to the area of treatment. When taken orally, patients may experience nausea, vomiting, stomach upset, or diarrhea as the medication passes through the digestive tract. Topical application on the skin can sometimes cause redness, itching, or a mild burning sensation. Some people using the oral suspension report a temporary bitter or unpleasant taste in the mouth. Most of these side effects do not require medical attention unless they become severe or persistent. Always report new or worsening symptoms to your doctor.
There is no known direct chemical interaction between Nystatin and alcohol, meaning alcohol does not stop the drug from working. However, if you are treating oral thrush, alcohol can act as an irritant to the already inflamed tissues in your mouth, potentially delaying the healing process. Furthermore, alcohol can sometimes weaken the immune system, which is your body's primary defense against fungal overgrowth. For the best results, it is usually recommended to avoid alcohol until the infection has completely cleared. Always consult your healthcare provider for personalized advice regarding alcohol consumption during treatment.
Nystatin is generally considered one of the safer antifungal options during pregnancy because it is not absorbed into the mother's bloodstream. This lack of systemic absorption means the developing fetus is not exposed to the medication. It is frequently used to treat vaginal yeast infections or oral thrush in pregnant women when deemed necessary by a physician. While classified as FDA Category C, its long history of use has not shown a link to birth defects. However, you should always inform your doctor if you are pregnant or planning to become pregnant before starting any new medication. They will weigh the benefits of treatment against any potential risks.
Most patients begin to see an improvement in their symptoms within 24 to 72 hours after starting Nystatin. For oral thrush, the white patches may begin to diminish, and soreness usually decreases fairly quickly. However, it is essential to continue using the medication for the full duration prescribed by your doctor, even if you feel better. Usually, treatment continues for at least 48 hours after all symptoms have completely disappeared. If you do not see any improvement after 14 days of consistent use, you should contact your healthcare provider. They may need to re-evaluate the diagnosis or check for a resistant strain of fungus.
Yes, you can stop taking Nystatin suddenly without experiencing withdrawal symptoms, as the drug does not create a physical dependence. However, you should only stop the medication once you have completed the full course prescribed by your healthcare provider. Stopping too early, even if the symptoms seem to be gone, can allow the remaining fungi to multiply and cause the infection to return. This can sometimes lead to the development of fungal resistance, making future infections harder to treat. Always finish the entire bottle or tube as directed by your medical professional. If you experience a severe side effect, contact your doctor before stopping.
If you miss a dose of Nystatin, you should take it as soon as you remember to maintain the necessary concentration of the drug at the infection site. However, if it is nearly time for your next scheduled dose, it is better to skip the missed dose and simply continue with your regular schedule. You should never 'double up' or take two doses at once to make up for a missed one. Consistency is key with antifungal therapy, so try to set a reminder to take your doses at the same times each day. If you miss multiple doses, notify your healthcare provider for further instructions.
Nystatin is not known to cause weight gain. Because the medication is not absorbed into the systemic circulation, it does not affect the metabolic processes or hormones that typically lead to drug-induced weight changes. Side effects are generally limited to the digestive tract or the skin surface. If you experience unexplained weight gain while taking Nystatin, it is likely due to another factor or an underlying medical condition. You should discuss any significant changes in your weight with your healthcare provider. They can help identify the root cause and determine if it is related to your overall health or other medications.
Nystatin can generally be taken with most other medications because it does not enter the bloodstream and does not interact with liver enzymes. However, you should avoid using other topical products or mouthwashes at the same time as Nystatin, as they might wash the medication away or prevent it from coating the infected area. There is also a potential interaction with yeast-based probiotics (like Saccharomyces boulardii), as Nystatin may kill the beneficial yeast in the probiotic. It is always best to provide your doctor with a full list of all prescriptions, over-the-counter drugs, and supplements you are taking. This ensures that your entire treatment regimen is safe and effective.
Yes, Nystatin is widely available as a generic medication in various forms, including the oral suspension, topical cream, and powder. Generic versions are required by the FDA to have the same active ingredient, strength, and effectiveness as the original brand-name versions (such as Mycostatin or Nilstat). Choosing the generic version is often a more cost-effective option for patients and is usually covered by most insurance plans. Your pharmacist can help you identify the generic equivalent of the Nystatin product your doctor has prescribed. Regardless of whether you use a brand-name or generic version, the clinical effects and safety profile remain the same.