acyclovir vs nystatin
PlainMeds reviewed this comparison against our methodology in August 2026. It places FDA and CMS record fields side by side, without recommending either medication.
Side-by-side comparison of acyclovir and nystatin. Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.
Acyclovir is an antiviral medicine. It is used to treat infections caused by certain viruses.
Nystatin topical powder is an antifungal medicine. It treats fungal infections on your skin.
Acyclovir is used to treat shingles, which is caused by herpes zoster. It also treats genital herpes, both the first time you have it and when it comes back. Acyclovir can also treat chickenpox.
This medicine treats skin infections caused by Candida, a type of fungus. It is for use on the skin only. Do not use in your mouth, vagina, eyes, or for infections inside your body.
Acyclovir stops the virus from growing and spreading. It does this by interfering with the virus's ability to make copies of itself. This helps your body fight off the infection.
Nystatin is an antifungal medicine. It works by killing the fungus or stopping its growth. This helps to clear up the infection on your skin.
- • Malaise (feeling unwell)
- • Nausea
- • Diarrhea
- • Allergic reactions
- • Burning
- • Itching
- • Rash
- • Eczema
- Fatigue 7,612
- Diarrhoea 7,064
- Pneumonia 5,471
- Nausea 5,328
- Pyrexia 4,719
- Nausea 1,963
- Fatigue 1,799
- Diarrhoea 1,786
- Pneumonia 1,613
- Dyspnoea 1,483
Acyclovir can cause nervous system problems, especially in older adults or people with kidney problems. Tell your doctor if you have kidney problems before taking this medicine.
You should not use this medicine if you are allergic to any of its ingredients.
Tell your doctor if you are pregnant or plan to become pregnant. It is not known if acyclovir will harm an unborn baby. Talk to your doctor about the risks and benefits of taking acyclovir while breastfeeding.
Tell your doctor if you are pregnant or breastfeeding before using this medicine. It is not known if nystatin topical powder is harmful to an unborn baby or passes into breast milk.
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How to Read This acyclovir vs nystatin Comparison
acyclovir is classified in the Antiviral (Nucleoside Analog) drug class, while nystatin sits within the Polyene Antifungal class. Drugs from different classes work through distinct mechanisms, so a head-to-head comparison illustrates trade-offs rather than equivalence. Both drugs are prescription-only, so a licensed provider must authorize use.
Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, acyclovir has 30,194 submissions while nystatin has 8,644. Those figures reflect cumulative reporting volume, not per-patient risk, so older, widely dispensed drugs typically look worse on count alone. No direct interaction between these two drugs is listed in our FDA-derived dataset, though co-prescription still warrants pharmacist review. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.
A table cannot represent individual circumstances. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This registry does not provide medical, treatment, substitution, or medication-change directions for acyclovir or nystatin.
Registry boundary: This comparison displays source-record fields and does not provide individualized medical direction.