What is Nystatin and How Does It Work?
Nystatin is an antifungal medication used to treat Candida yeast infections [1.6.2]. It was first discovered in 1950 and is derived from the bacterium Streptomyces noursei [1.6.2]. This medication is effective for infections in various parts of the body, including the skin (like diaper rash), mouth (oral thrush), and digestive tract [1.6.2, 1.2.1].
Its mechanism of action involves binding to ergosterol, a crucial component of the fungal cell membrane. This binding action creates pores in the membrane, causing the cell's contents to leak out, which ultimately kills the fungus [1.6.5, 1.6.3]. A key feature of nystatin is that it is not significantly absorbed into the bloodstream when taken orally; it works locally where it is applied and is mostly eliminated unchanged in the feces [1.6.4, 1.4.1]. This lack of systemic absorption contributes to it being generally well-tolerated [1.4.1].
Does Nystatin Upset the Stomach? Unpacking the Side Effects
Yes, oral nystatin can upset the stomach. Gastrointestinal (GI) issues are among the most commonly reported side effects [1.3.3]. While generally considered mild, they can cause discomfort for patients [1.3.4].
The most frequent stomach-related side effects include:
- Nausea and Vomiting [1.2.4, 1.2.6]
- Diarrhea [1.2.2, 1.2.3]
- Stomach Pain or Cramps [1.2.4]
- Bloating [1.2.2, 1.2.8]
These symptoms can occur because the medication acts directly within the gastrointestinal tract to eliminate fungal infections [1.4.1]. Sometimes, diarrhea can also be a symptom of the gut infection itself, which may improve as the nystatin begins to work [1.2.1]. It's important to note that while doses exceeding five million units daily have been linked to nausea and GI upset, serious toxicity from an overdose is not typically reported [1.6.4].
Comparing Nystatin Formulations and GI Side Effects
Nystatin comes in different forms, primarily an oral suspension (liquid) and tablets, and the likelihood of stomach upset can vary between them [1.2.1].
- Oral Suspension: This liquid form is often prescribed for oral thrush, where the instructions are typically to "swish and swallow" or "swish and spit" [1.4.6]. When swallowed, it can lead to GI side effects like nausea or diarrhea [1.2.1]. If the medication is mostly spit out, systemic effects are minimal. The taste of the liquid can also be unpleasant for some, contributing to nausea [1.5.1].
- Oral Tablets: These are prescribed for fungal infections in the gut (intestinal candidiasis) [1.4.6]. Since they are designed to be swallowed and work within the intestines, they are more commonly associated with side effects like stomach pain, nausea, and diarrhea [1.2.4, 1.2.1].
| Feature | Oral Suspension | Oral Tablets |
|---|---|---|
| Primary Use | Oral Thrush (Oropharyngeal Candidiasis) [1.4.6] | Intestinal Candidiasis [1.4.6] |
| GI Side Effect Likelihood | Less common (if spit), more common (if swallowed) [1.2.1] | Common [1.2.4] |
| Common GI Symptoms | Nausea, mouth irritation, diarrhea (if swallowed) [1.2.1] | Nausea, vomiting, diarrhea, stomach pain [1.2.6] |
| Absorption | Minimal systemic absorption [1.4.1] | Acts directly in the GI tract [1.6.3] |
Strategies for Managing Nystatin-Related Stomach Upset
If you experience stomach discomfort while taking nystatin, there are several effective strategies to help manage the symptoms:
- Take with Food: For nystatin tablets, taking them with food may help reduce stomach-related side effects [1.5.1, 1.5.4]. For the liquid form, the NHS recommends taking it after a meal or snack [1.5.2].
- Adjust Your Diet: Stick to simple, bland meals and avoid rich, spicy, or fried foods that can worsen an upset stomach [1.5.2, 1.2.1].
- Stay Hydrated: If you experience diarrhea, it's crucial to drink plenty of fluids like water to prevent dehydration [1.5.2].
- Manage the Taste: The unpleasant taste of the liquid suspension can contribute to nausea. Some pharmacists can add flavoring. Alternatively, eating something cold like an ice pop before your dose can help numb your taste buds [1.5.1].
- Don't Eat or Drink Immediately After (Liquid Form): To allow the liquid suspension to work effectively in the mouth, you should avoid eating or drinking for at least 30 minutes after taking it [1.5.3, 1.6.5].
When to Consult a Healthcare Provider
While most side effects are mild and resolve on their own, you should contact your doctor if you experience [1.2.1, 1.2.8]:
- Severe or persistent stomach pain, vomiting, or diarrhea.
- Bloody diarrhea [1.2.6].
- Signs of a severe allergic reaction, such as hives, rash, difficulty breathing, or swelling of the face, lips, tongue, or throat [1.2.4, 1.4.5].
- A very rare but serious skin reaction called Stevens-Johnson syndrome [1.2.4].
Conclusion
So, does nystatin upset the stomach? The answer is yes, it's a common and well-documented side effect, particularly with oral tablets designed for intestinal infections [1.2.4, 1.3.3]. However, these gastrointestinal issues are typically mild and manageable [1.3.4, 1.3.5]. The medication's benefits in treating fungal infections often outweigh the temporary discomfort. By taking the medication with food, adjusting your diet, and staying hydrated, most people can successfully complete their course of treatment [1.5.1, 1.5.2]. Always follow your doctor's instructions and report any severe or persistent side effects.
For more information, you can consult the NHS page on nystatin.
