acyclovir vs fluconazole
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 fluconazole. Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.
Zovirax
Diflucan
Acyclovir is an antiviral medicine. It is used to treat infections caused by certain viruses.
Fluconazole is an antifungal medicine. It is used to treat infections caused by fungus.
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.
Fluconazole treats vaginal yeast infections. It also treats yeast infections in the mouth and esophagus. Fluconazole can also treat urinary tract infections, peritonitis, systemic Candida infections, and pneumonia. It can also treat cryptococcal meningitis. Fluconazole can also prevent candidiasis in patients undergoing bone marrow transplantation.
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.
Fluconazole works by stopping the growth of fungi. It blocks the fungus from producing a substance it needs to grow. This helps to clear up the infection.
- • Malaise (feeling unwell)
- • Nausea
- • Diarrhea
- • Headache
- • Nausea
- • Abdominal pain
- Fatigue 7,612
- Diarrhoea 7,064
- Pneumonia 5,471
- Nausea 5,328
- Pyrexia 4,719
- Pyrexia 4,121
- Nausea 3,697
- Diarrhoea 3,538
- Fatigue 3,151
- Pain 3,123
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.
Coadministration of other drugs known to prolong the QT interval and which are metabolized via the enzyme CYP3A4 such as erythromycin, pimozide, and quinidine are contraindicated in patients receiving fluconazole.
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 plan to become pregnant. Fluconazole may not be safe for your baby. Talk to your doctor about breastfeeding while taking fluconazole.
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How to Read This acyclovir vs fluconazole Comparison
acyclovir is classified in the Antiviral (Nucleoside Analog) drug class, while fluconazole sits within the Azole 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 fluconazole has 17,630. 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 fluconazole.
Registry boundary: This comparison displays source-record fields and does not provide individualized medical direction.