acyclovir vs terbinafine
Side-by-side comparison of acyclovir and terbinafine Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.
Zovirax
Lamisil
Acyclovir is an antiviral medicine. It is used to treat infections caused by certain viruses.
Terbinafine is an antifungal medicine. It is used to treat fungal infections of the fingernails and toenails.
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.
Terbinafine treats onychomycosis, a fungal infection of the toenails or fingernails. Before you start taking this medicine, your doctor should take a nail sample. This is to make sure the infection is caused by a fungus.
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.
Terbinafine belongs to a class of medicines called allylamine antifungals. It works by stopping the growth of fungi. This eventually kills the fungus causing the infection.
- • Malaise (feeling unwell)
- • Nausea
- • Diarrhea
- • Headache
- • Diarrhea
- • Rash
- • Upset stomach
- • Abnormal liver enzyme tests
- 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
- The medicine is not working 685
- Skin rash 391
- Itching 316
- Tiredness 300
- Feeling sick to your stomach 280
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.
Terbinafine can cause liver problems, including liver failure. Your doctor should check your liver before you start taking it and regularly while you are taking it. Tell your doctor right away if you have nausea, loss of appetite, tiredness, vomiting, pain in your upper right belly area, yellowing of the skin or eyes, dark urine, or pale stools. If you have taste changes, stop taking terbinafine. These changes can be severe, long-lasting, or even permanent. Tell your doctor if you feel depressed or have other mood changes.
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.
Talk to your doctor if you are pregnant or plan to become pregnant. It is not known if terbinafine will harm your unborn baby. Terbinafine passes into breast milk. Talk to your doctor about the risks and benefits of breastfeeding while taking this medicine.
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How to Read This acyclovir vs terbinafine Comparison
acyclovir is classified in the Antiviral (Nucleoside Analog) drug class, while terbinafine sits within the Allylamine 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 terbinafine has 1,972. 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 terbinafine — 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.