Anti-infective
Terbinafine
An antifungal for skin and nails — The usual oral treatment for fungal nail and stubborn skin infections.
Education and reference only. This is a plain-language class overview — it deliberately contains no doses. Always check the current Summary of Product Characteristics (SmPC), the BNF and your local formulary before prescribing or administering any medicine.
What it is
Terbinafine treats fungal infections of the skin and nails. The oral tablets are used for nail infections and more extensive skin infections; a cream is used for localised problems such as athlete's foot.
How it works
It blocks an enzyme fungi need to build their cell membranes, causing a toxic build-up that kills the fungus. It concentrates well in skin, nails and hair, which is why it is effective for these otherwise hard-to-reach infections.
In practice
In practice terbinafine is the first-line oral antifungal for fungal nail infections and for widespread or resistant skin fungal infections, and a practical point is that it is worth confirming the diagnosis (e.g. by sampling the nail) before committing someone to a long course, because nail treatment takes months and not all thickened nails are fungal. The main safety considerations with the oral form are the liver and blood: liver function is checked and patients are told to report jaundice, dark urine or persistent nausea, and to mention any sore throat or fever. It can also disturb or reduce taste, which usually recovers after stopping. The topical (cream) form, used for athlete's foot and similar, carries very little of this systemic risk.
Examples
Practical use
How to take it & use it well
- For skin or nail infections taken by mouth, take terbinafine once daily, with or without food, at about the same time each day.
- Complete the full course even if the infection looks better, as fungal infections clear slowly and stopping early can let them return.
- Be prepared for long treatment with nail infections, since healthy nail can take many months to fully grow out.
- For cream or gel forms, apply a thin layer to the affected area and surrounding skin as directed, and wash your hands afterwards.
- Tell your prescriber if you develop yellowing of the skin or eyes, dark urine, persistent nausea or tummy pain, as these can signal a liver problem.
- Report any rash, mouth ulcers or persistent change in taste, and do not ignore severe skin reactions.
Common uses
- Fungal nail infections (oral)
- Widespread or resistant skin fungal infections (oral)
- Athlete's foot and localised skin infections (topical)
Monitoring
- Liver function with oral treatment
- Response (slow for nails — months)
- Any taste change or signs of blood/liver problems
Weighing it up
Advantages & disadvantages
Advantages
- Very effective against the fungi that cause athlete's foot, ringworm and fungal nail infections.
- Oral courses can cure stubborn nail and skin infections that creams alone cannot reach.
- Available as both a cream for milder skin infections and tablets for more extensive or nail disease.
- Once-daily oral dosing is straightforward to take.
Disadvantages
- Oral terbinafine can rarely affect the liver, so symptoms suggesting liver trouble must be reported quickly.
- Nail courses are long, often lasting several months, which calls for patience and good adherence.
- It can cause a change or loss of taste that usually recovers after stopping but can be unpleasant.
- Stomach upset, headache and skin rashes can occur, and serious skin reactions are rare but need urgent attention.
Key safety principles
What to watch for
- Oral use can affect the liver — check liver function and report jaundice, dark urine or persistent nausea.
- Rare blood disorders — report sore throat, fever or unusual bruising.
- Taste disturbance or loss can occur (usually reversible); confirm the diagnosis before long nail courses.
Key interactions
What to avoid or check alongside
- Terbinafine can raise levels of some medicines processed by a particular liver pathway, including certain antidepressants such as tricyclics, increasing their side effects.
- It may affect the action of some heart-rhythm and beta-blocker medicines, so report any new dizziness or palpitations.
- Rifampicin can lower terbinafine levels and reduce its effect, while cimetidine can raise them.
- Caffeine may have a stronger effect while taking terbinafine, which can add to jitteriness.
- Always tell your pharmacist about all your medicines before starting oral terbinafine.
Patient & carer advice
- Nail treatment takes months as the new nail grows out
- Report yellowing of the skin/eyes, dark urine, or a sore throat and fever
- The cream form is low-risk; the tablets need the above care
Use with
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Answers
Terbinafine: frequently asked questions
Why does fungal nail treatment take so long?
The medicine clears the fungus, but the damaged nail itself has to grow out and be replaced by healthy nail. As nails grow slowly, oral courses often last several months before the nail looks normal.
Can terbinafine affect my liver?
Liver problems are rare but possible with the tablets. Tell your prescriber promptly if you notice yellowing of the skin or eyes, dark urine, pale stools, persistent nausea or tummy pain.
Is the taste change from terbinafine permanent?
Usually not. Some people notice a reduced or altered sense of taste during treatment, which generally returns to normal after the course finishes, though it can take a few weeks.
Do I need the tablets or will a cream do?
Mild skin infections like athlete's foot often respond to the cream. More extensive infections and nail infections usually need oral tablets, which your prescriber will decide based on your case.
Authoritative sources
Always verify against the source
This overview is for orientation. For doses, interactions, contra-indications and the full monograph, use:
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