Ketoconazole (Nizoral) in Dogs, Cats, and Other Pets - Pet Education

Ketoconazole cannot be applied in pregnant dogs, as the drugs will cause the death of the fetuses.
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CYP3A inhibition by ketoconazole has also been reported in cats. Shah et al. showed in his in vitro experiment using feline hepatic microsomes that ketoconazole can inhibit midazolam 1′-hydroxylation in a non-competitive manner. They estimated the inhibition constant of ketoconazole to be 2 μM. Although this value might be quite low to cause drug–drug interaction, it is more than 20-fold higher compared to the estimated value in dogs . Because of this fact, ketoconazole related drug–drug interaction may occur at smaller extent compared with those in dogs and humans. Shah et al. have demonstrated that the decrease in quinidine clearance by ketoconazole treatment was less than a half in cats. However, they showed a time-dependent decrease in midazolam 1′ hydroxylation by pre-incubation of feline microsomes with ketoconazole. This suggests that ketoconazole has a mode of mechanism based inhibition in cats, although the mode has not been reported in dogs and humans. McAnulty and Lensmeyer showed in his study the inhibitory effects of ketoconazole on cyclosporine pharmacokinetics, which can be implied from two times maximum cyclosporine blood concentration in cats treated orally with ketoconazole.
Ketoconazole is sometimes used in dogs and cats to treat fungal and bacterial skin infections.
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Ketoconazole is a triazole antimycotic drug used in severe in dogs that are non-responsive to , , or other azole drugs such as or . Eye problems (cataracts) have been associated with administration of ketoconazole in dogs.
Photo provided by FlickrKetoconazole has caused changes in the hair coat of animals, causing a lightening of the hair color in dogs and a drying of the hair coat in cats.
Photo provided by FlickrEven if ketoconazole is not FDA approved for veterinarian use, it is typically safe and will cause minimal side effects in dogs.
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Although ketoconazole has been used extensively in dogs for the treatment of various fungal infections, information about adverse effects is mainly anecdotal. Common adverse effects in humans include dose-dependant anorexia, nausea and vomiting, allergic rashes and pruritus. Drug-induced hepatitis is very rare, but potentially fatal. The aim of this study was to evaluate the type and frequency of adverse effects associated with ketoconazole therapy in dogs treated for skin diseases and any possible influence of dosage, duration of therapy, signalment or concurrent medication. The medical records of 632 dogs treated with ketoconazole (2.6-33.4 mg/kg) were reviewed. Adverse effects occurred in 14.6% (92 dogs) and included vomiting (7.1%), anorexia (4.9%), lethargy (1.9%), diarrhea (1.1%), pruritus (0.6%), erythema (0.3%) and other adverse effects (2.5%). Of the dogs with other adverse effects, four of 16 (25%) were ataxic and three of these received concurrent ivermectin. Adverse effects were significantly more often recorded in dogs concurrently treated with ciclosporin (P = 0.034) or ivermectin (P = 0.007). Increased liver enzyme levels were reported rarely, and icterus was not seen in any of the dogs. However, monitoring liver enzymes during therapy is recommended, although this might not necessarily prevent severe idiosyncratic hepatotoxicity.Ketoconazole, the active ingredient of Nizoral, is an anti-fungal drug which may be used to treat a variety of problems in dogs. It works by blocking the formation of cortisol in the body’s adrenal glands. There are several things you must be aware of when treating your dog with this drug, so it’s crucial that you have the approval and guidance of a trained vet. Ketoconazole is an antifungal medicine used predominantly for treating fungal infections, though it has additional properties which can help in the treatment of truncal alopecia. In the past it was used for Cushing’s disease but this is no longer common as the medicine can place extra stress on the liver, even leading to liver failure in rare cases. It is derived from the organic compound imidazole and works by inhibiting the process vital for the growth of fungus. In large doses it can puncture holes in the cell membrane of fungal structures destroying them by causing essential components to leak out.

If you notice your dog becoming patchy and shedding large amounts of hair you should speak to the vet for diagnosis as they could have mange or lupus.

Fungistatic Vs Fungicide: Know The Difference

Derivatives of imidazole including ketoconazole are usually fungistatic. This means that instead of directly killing fungi, they limit its growth and rely on natural processes to eliminate the infection from the body. When used in higher doses, they can become fungicidal and attack cell membranes. Fungistatic drugs are more often used as they tend to be safer, but they may not be a good option for treating life threatening infections or when the dog’s immune system function is reduced. If you’re interested in further comparing the differences you can check out the page on .

Ketoconazole is commonly prescribed by vets, even though it has not yet been approved by the FDA for veterinary purposes. Some ‘azole’ antifungal medicines have been approved for veterinary use by the FDA, however, including thiabendazole. When treating certain conditions like aspergillosis, thiabendazole is thought to be just as effective. You can .

Even though ketoconazole isn’t FDA-approved, many veterinary professionals consider it to be safe for use. Safety regarding the external use of ketoconazole creams and shampoos has not yet been established, however there are typically less side effects reported following topical use aside from skin irritation in rare cases.

Contraindications & Drug Interactions

There aren’t many contraindications associated with this medicine, though it could be unsuitable for dogs with liver problems, especially when given at higher doses. Drug interactions are relatively extensive.