What is terbinafine?
Terbinafine (brand name Lamisil®) is an oral, systemic antifungal used primarily to treat skin fungal infections, but also systemic fungal infections.
Its use in cats and dogs to treat fungal infections is “off label” or “extra label”. Many drugs are commonly prescribed for off-label use in veterinary medicine. In these instances, follow your veterinarian’s directions and cautions carefully, as they may be significantly different from those on the label.
How is terbinafine given?
- Terbinafine is given orally (by mouth) in the form of tablets or granules. It may also be compounded into a liquid.
- It should be given with food, especially if vomiting is a problem. The granule form should be mixed with soft food.
This medication can take a few weeks before full effects are noted, but gradual improvements are usually noticeable after a few days.
What if I miss giving my pet the medication or my shipment is late?
If you miss a dose, give it as soon as you remember, and then continue with the regular dosing schedule. However, if it is almost time for the next dose, skip the missed dose and resume the regular dosing schedule. Do not give the pet two doses at once.
Are there any potential side effects?
This medication is generally well tolerated, but studies in veterinary patients are limited. Possible side effects may include:
- gastrointestinal effects, such as vomiting, lack of appetite, and diarrhea
- excessive panting
- elevated liver enzymes
In cats, lethargy and facial itchiness has been reported.
This short-acting medication should stop working within 24 hours, although effects can be longer in pets with liver or kidney disease.
Are there any risk factors for this medication?
Terbinafine should NOT BE USED in pets that:
- are hypersensitive to it
- are lactating
- have active or chronic liver disease or decreased kidney function (if it must be used, a lower dose should be considered)
Terbinafine should be USED WITH CAUTION in breeding and pregnant pets, as safety has not been determined.
Are there any drug interactions I should be aware of?
Several medications should be used with caution when given with terbinafine, including:
- cyclosporine
- fluconazole
- beta-blockers
- selegiline
- SSRIs
- tricyclic antidepressants
Be sure to tell your veterinarian about any medications (including vitamins, supplements, or herbal therapies) that your pet is taking.
Is there any monitoring that needs to be done with this medication?
- Pets taking this medication should have a baseline liver panel prior to starting the medication.
- If your pet uses this medication long-term, your veterinarian will perform periodic blood tests to check liver function and monitor for any changes or elevations.
How do I store terbinafine?
- Store tablets and granules at room temperature (25°C or 77°F).
- Store in a tight container, away from moisture and light.
What should I do in case of emergency?
If you suspect an overdose or an adverse reaction to the medication, call your veterinary office immediately. If they are not available, follow their directions in contacting an emergency facility.
