Terbinafine

What is this medication for?

• Dermatophytosis, Malassezia dermatitis (adjunct), nasal aspergillosis (adjunct with topical therapy)

How is it given?

Give exactly as your veterinarian prescribed — never change the dose or stop on your own unless your veterinarian has told you to.

What if I miss a dose?

• Give it as soon as you remember — unless it is almost time for the next dose (then skip the missed one; never double up).
• Call your clinic if you miss more than one dose in a row.

Side effects — what should I watch for?

Effects listed as common in this handout

• Vomiting, inappetence, diarrhea (Most common)
• Facial itching (Reported)
• Lethargy (Case report)

Worth a phone call to your veterinarian

• ↑ Liver enzymes (Possible, more with continuous high-dose vs. pulse dosing)

⚠️ Contact your veterinarian or an emergency clinic IMMEDIATELY if you notice

• Trouble breathing, collapse, seizures, severe vomiting or diarrhea, facial swelling, or pale gums

Before starting (or refilling), tell your veterinarian if your pet:

• has or has had: Hypersensitivity
• has or has had: Active/chronic liver disease, significant renal impairment (manufacturer does not recommend use)

• is pregnant, nursing, or used for breeding
• is taking any other medications, supplements, or flea/tick products, including:
  • Cyclosporine
  • Rifampin
  • Beta-blockers, MAOIs (amitraz, selegiline), SSRIs, TCAs

Storage and handling

Room temperature, protect from light. Compounded suspension (Ora-Sweet) stable ~42 days.

Good to know

• Comparatively few drug interactions vs. azole antifungals — doesn't work through CYP3A/steroidogenesis pathway, so it's often better tolerated in animals on multiple other medications.
• Veterinary doses are much higher than human doses (30–40 mg/kg vs. human ~3–6 mg/kg) — do not extrapolate from human dosing.
• Pulse dosing in cats (1 week on, 3 weeks off) can be as effective as continuous dosing with fewer stomach/intestinal/hepatic side effects.