If you’ve been told you need an antifungal, chances are you’ve heard the names terbinafine and griseofulvin. Both are used for nail and skin infections, but they don’t work the same way and they aren’t interchangeable. In this guide we’ll break down what each drug does, how you take it, and what you might feel while on it. By the end you’ll know which one fits your situation better.
Terbinafine is a synthetic allylamine. It blocks the enzyme that builds the fungal cell wall, so the fungus can’t grow and eventually dies. Because it hits the wall directly, it works fast – you often see improvement within a couple of weeks for skin infections and a few months for nail problems.
Griseofulvin is an older drug derived from mold. Instead of breaking the wall, it slips into the fungus’s structure and stops it from dividing. This means the drug needs time for the infected cells to grow out and be replaced by healthy tissue. That’s why treatment can stretch 6‑12 weeks for skin, and up to a year for toenail infections.Both medicines are taken orally, but topical versions of terbinafine also exist for athlete’s foot and similar issues. Griseofulvin only comes in pills.
Dosage is a simple way to see the gap. A typical terbinafine course for nail fungus is 250 mg once daily for 12 weeks. For skin fungus it can be 250 mg once daily for 2‑4 weeks. Griseofulvin dosing is weight‑based – roughly 500‑1000 mg per day split into two doses, and you keep taking it for months.
Side‑effects also set them apart. Terbinafine can cause upset stomach, headache, or a bitter taste, and in rare cases liver issues. Doctors usually order a liver test before you start and after a few weeks. Griseofulvin is known for causing more skin rash, nausea, and sometimes vivid dreams. It can also lower vitamin A levels, so supplements might be needed.
Cost and access matter, too. Terbinafine is now generic and often cheaper than griseofulvin, especially when you shop reputable online pharmacies. Griseofulvin’s price can vary, and some insurers label it as “non‑preferred,” which may mean higher out‑of‑pocket costs.
Which one should you pick? If you need a quick fix for a small skin infection, terbinafine’s short course and fast results usually win. For stubborn toenail infections that haven’t responded to other drugs, some doctors still prescribe griseofulvin, but many prefer newer options like itraconazole or even a longer terbinafine regimen.
Before you decide, talk to your pharmacist or doctor about any liver problems, pregnancy, or other meds you take. Both drugs can interact with other prescriptions, so a quick medication review saves headaches later.
Bottom line: terbinafine is fast, usually cheaper, and has a simpler dosing schedule. Griseofulvin is slower, may need blood tests, and often causes more digestive upset. Knowing these points helps you choose the right treatment and get back to healthy skin and nails faster.
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