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Ketoconazole

Prescription
Imidazole antifungal
Last reviewed 19 Apr 2026 · PetCare.AI Editorial Team
Species
Dog, Cat
Brands
4 available
Interactions
7 documented
Formulations
2

Mechanism of action

Inhibits fungal CYP450 lanosterol 14-alpha-demethylase; also inhibits mammalian steroidogenesis (cortisol, testosterone), used off-label for Cushing's disease

At a glance

Class
Imidazole antifungal
Schedule
Prescription
Storage
Store below 25°C, protect from moisture

Dosing

🐕

Dog

Dermatophytosis / Malassezia dermatitis
Dose
5–15 mg/kg
Route
PO
Frequency
SID to BID
Max dose
400 mg/dose; 800 mg/day
Duration: 4–8 weeks; give with food for absorption
Hyperadrenocorticism (Cushing's)
Dose
5–15 mg/kg
Route
PO
Frequency
BID
Max dose
600 mg/dose; 1200 mg/day
Duration: Long-term; palliative
🐈

Cat

Dermatophytosis (not first choice)
Dose
5–10 mg/kg
Route
PO
Frequency
SID
Max dose
50 mg
Duration: 4–8 weeks; itraconazole preferred in cats

Formulations

💊

Tablet — 1

Strength
200mg
Available in India
💊

Shampoo — 1

Strength
2%
Available in India

Storage

Store below 25°C, protect from moisture

Safety

Absolute contraindications — do not use

  • Hepatic disease
    Most hepatotoxic azole
  • Pregnancy
    Teratogenic and anti-androgenic

Use with caution

  • Cats
    Higher hepatotoxicity risk; prefer itraconazole
  • Concurrent antacids or H2 blockers
    Requires acidic pH for absorption

Adverse effects

Common
Anorexia
Vomiting
Diarrhoea
Serious
Hepatotoxicity (dose-dependent)
Adrenal suppression
Teratogenicity
Thrombocytopenia

Monitoring parameters

Hepatic enzymes (ALT, ALP) every 2 weeks initiallyCortisol levels (if treating Cushing's)Appetite and body weight

Interactions

Major — 1

Trilostane
major
Both inhibit adrenal steroidogenesis; combined use risks severe hypoadrenocorticism (Addisonian crisis)
Management: Do not use concurrently. Allow adequate washout between drugs.

Moderate — 6

Cyclosporine
moderate
Ketoconazole inhibits CYP3A4, significantly increasing cyclosporine levels (used therapeutically to reduce cyclosporine dose/cost)
Management: Intentional combination in veterinary practice. Reduce cyclosporine dose by 50-75% when adding ketoconazole. Monitor cyclosporine levels.
Phenobarbital
moderate
Phenobarbital induces hepatic enzymes, reducing ketoconazole levels; ketoconazole may increase phenobarbital levels
Management: Monitor both drug levels. May need dose adjustments.
Famotidine
moderate
H2 blockers raise gastric pH; ketoconazole requires acidic environment for absorption
Management: Give ketoconazole at least 2 hours before famotidine, or use fluconazole instead (pH-independent absorption).
Ranitidine
moderate
H2 blockers reduce gastric acid, decreasing ketoconazole absorption by up to 95%
Management: Separate administration by 2+ hours. Consider switching to fluconazole.
Pantoprazole
moderate
PPIs raise gastric pH, reducing ketoconazole absorption which requires acidic environment
Management: Separate administration by 2 hours. Give ketoconazole with acidic food/drink. Consider itraconazole instead.
Esomeprazole
moderate
PPIs raise gastric pH, markedly reducing ketoconazole bioavailability
Management: Avoid combination. If antifungal needed with PPI therapy, use itraconazole or fluconazole.

Brands

International

Nizoral
Janssen

India

Fungiket
Cipla
Ketovate
Mankind
Ketocip
Cipla

FAQs

Frequently asked questions

›What is Ketoconazole?
Ketoconazole is a imidazole antifungal used in pets. Inhibits fungal CYP450 lanosterol 14-alpha-demethylase; also inhibits mammalian steroidogenesis (cortisol, testosterone), used off-label for Cushing's disease
›What is Ketoconazole used for in pets?
Ketoconazole is used in veterinary medicine for: Dermatophytosis / Malassezia dermatitis; Hyperadrenocorticism (Cushing's); Dermatophytosis (not first choice).
›What is the Ketoconazole dose for dogs?
For dogs, Ketoconazole is typically dosed as follows — Dermatophytosis / Malassezia dermatitis: 5–15 mg/kg PO SID to BID; Hyperadrenocorticism (Cushing's): 5–15 mg/kg PO BID. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›What is the Ketoconazole dose for cats?
For cats, Ketoconazole is typically dosed as follows — Dermatophytosis (not first choice): 5–10 mg/kg PO SID. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›What are the side effects of Ketoconazole?
Common: Anorexia, Vomiting, Diarrhoea. Serious (call your vet immediately): Hepatotoxicity (dose-dependent), Adrenal suppression, Teratogenicity, Thrombocytopenia.
›Does Ketoconazole need a prescription?
Yes. Ketoconazole is a prescription medication and should only be administered under veterinary supervision.
›When should Ketoconazole not be used?
Do not use Ketoconazole if: Hepatic disease; Pregnancy.

References

References

Textbooks & handbooks

  • Plumb, D.C. Plumb's Veterinary Drug Handbook. 10th ed., Wiley-Blackwell, 2023.
  • Vail, D.M., Thamm, D.H., & Liptak, J.M. (eds.). Withrow & MacEwen's Small Animal Clinical Oncology. 6th ed., Saunders/Elsevier, 2020.
  • Riviere, J.E., & Papich, M.G. (eds.). Veterinary Pharmacology and Therapeutics. 10th ed., Wiley-Blackwell, 2018.
  • National Research Council. Nutrient Requirements of Dogs and Cats. National Academies Press, Washington DC, 2006.
  • The Merck Veterinary Manual. Merck & Co., Online edition. https://www.merckvetmanual.com/

Clinical guidelines & consensus

  • Fletcher, D.J., Boller, M., Brainard, B.M., et al. "RECOVER Evidence and Knowledge Gap Analysis on Veterinary CPR." Journal of Veterinary Emergency and Critical Care, 2012;22(S1):S102–S131.
  • American Animal Hospital Association. 2018 AAHA Diabetes Management Guidelines for Dogs and Cats. AAHA Press.

Journals & peer-reviewed studies

  • Hogan, D.F., Fox, P.R., Jacob, K., et al. "Secondary prevention of cardiogenic arterial thromboembolism in the cat: The FAT CAT study." Journal of Veterinary Cardiology, 2015;17(Suppl 1):S306–S317.
  • Boswood, A., Häggström, J., Gordon, S.G., et al. "Effect of Pimobendan in Dogs with Preclinical Myxomatous Mitral Valve Disease and Cardiomegaly: The EPIC Study — A Randomized Clinical Trial." Journal of Veterinary Internal Medicine, 2016;30(6):1765–1779.
  • ASPCA Animal Poison Control Center. Toxicology and Poison Management Guidelines. American Society for the Prevention of Cruelty to Animals. https://www.aspca.org/pet-care/animal-poison-control

Regulatory & approvals

  • Central Drugs Standard Control Organisation (CDSCO), Government of India. Veterinary Drug Approval Registry, 1969–2026. Directorate General of Health Services. https://cdsco.gov.in/

Databases

  • Washington State University, College of Veterinary Medicine. Veterinary Clinical Pharmacology Laboratory (VCPL) — MDR1 Multidrug Sensitivity Database. https://vcpl.vetmed.wsu.edu/
Educational reference only
This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet. Find a vet near you →

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