acyclovir vs itraconazole
Side-by-side comparison of acyclovir and itraconazole Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.
Zovirax
Sporanox
Acyclovir is an antiviral medicine. It is used to treat infections caused by certain viruses.
Itraconazole capsules are an antifungal medicine. They treat fungal infections in your body.
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.
Itraconazole treats fungal infections like blastomycosis, histoplasmosis, and aspergillosis. It can help both people with healthy immune systems and those with weakened immune systems. It also treats onychomycosis, a fungal infection of the toenails or fingernails.
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.
Itraconazole stops fungi from growing. It does this by interfering with the production of a substance fungi need to build their cell membranes. This eventually kills the fungus and clears the infection.
- • Malaise (feeling unwell)
- • Nausea
- • Diarrhea
- • Nausea
- • Rash
- • Headache
- Tiredness 7,612
- Diarrhea 7,064
- Using the medicine for something it's not approved for 5,797
- Lung infection 5,474
- Feeling sick to your stomach 5,330
- Interaction with another medicine 1,118
- Medicine not working 1,100
- Using the medicine for something it's not approved for 606
- Fever 570
- Difficulty breathing 472
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.
Itraconazole can cause congestive heart failure. You should not take this medicine if you have heart problems. Itraconazole can also interact with many other medicines. Some of these interactions can be dangerous or even fatal. Check with your doctor about all the medicines you take.
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.
You should not take itraconazole if you are pregnant or plan to become pregnant. It can harm your unborn baby. Talk to your doctor about safe alternatives.
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How to Read This acyclovir vs itraconazole Comparison
acyclovir is classified in the Antiviral (Nucleoside Analog) drug class, while itraconazole 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 31,277 submissions while itraconazole has 3,866. 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 substitute for clinical judgment. Effectiveness, tolerability, drug-drug interactions with your other medications, kidney and liver function, pregnancy status, insurance formulary, and price all feed into a decision that only a licensed prescriber can make responsibly. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This page is for educational purposes only, is not medical advice, and should not be used to self-switch between acyclovir and itraconazole — always consult your physician or pharmacist first.
Important: This comparison is for informational purposes only. Drug effects vary between individuals. Always consult your doctor or pharmacist for personalized medical advice.