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If you're a UK dog groomer or owner who's heard of "Nizoral" for treating fungal infections in dogs, you need to know that we're actually talking about a prescription-only antifungal medication called ketoconazole. In the UK, the veterinary-licensed version is called Fungiconazol, and it carries strict regulations and serious safety warnings that every groomer must understand.
Here's what matters: ketoconazole (the active ingredient in both human Nizoral and veterinary Fungiconazol) is a powerful antifungal that fights yeast and ringworm infections in dogs. But here's the catch—oral ketoconazole can cause liver damage, interferes with many other medications, and is strictly prescription-only (POM-V) in the UK.[1] That means only a vet registered with the Royal College of Veterinary Surgeons can prescribe it.
As groomers, you play a vital role in spotting the early signs of fungal infections—that characteristic musty smell, greasy or flaky skin, constant itching. Your job is to recognise these symptoms and refer clients to their vet immediately, not to diagnose or recommend prescription treatments. This guide will help you understand what ketoconazole is, when vets use it, what the risks are, and what safer alternatives exist for grooming salon use.
Important Disclaimer
This article provides general information and educational guidance only. It is not veterinary medical advice. Ketoconazole (Fungiconazol) is a prescription-only medicine in the UK that must only be prescribed by a qualified veterinary surgeon. Dog groomers must never diagnose conditions, prescribe medications, or administer prescription treatments. If you observe signs of infection or skin disease during grooming, refer your client immediately to their veterinarian. Always follow vet instructions precisely when using any prescribed medicated products.
Oral ketoconazole (Fungiconazol) is classified as Prescription Only Medicine – Veterinary (POM-V) in the UK. This isn't just a technicality—it's a legal requirement that protects both you and the dogs in your care.[1]
POM-V medicines can only be supplied on a valid written prescription from a vet registered with the Royal College of Veterinary Surgeons (RCVS). The prescription must be signed, dated, and is only valid for six months.[2]
As a groomer, you absolutely cannot:
The CFSG (Canine & Feline Sector Group) guidelines, developed with the Pet Industry Federation, make this clear: groomers must "only use medicated products as per vet instructions."[3] Your role is to be the first line of defence—spotting problems early and getting dogs to professional care.
Dog groomers are often the first people to notice skin and coat problems. You're handling these dogs regularly, seeing them up close, and noticing changes their owners might miss. That makes you invaluable—but it doesn't make you a vet.
Fungal infections have distinctive symptoms that you'll encounter during grooming. When you spot these signs, document them and refer the client to their vet immediately.
Key symptoms of Malassezia (yeast) or dermatophyte (ringworm) infections include:
Yeast infections typically show up in the warm, moist areas—ears, lips, armpits, groin, and between the toes. Ringworm can appear anywhere but often starts as circular patches of hair loss.
Oral ketoconazole is prescribed by vets to fight two main types of fungal infection: yeast dermatitis and ringworm. Understanding these infections helps you recognise when a dog needs veterinary care.
Malassezia pachydermatis is a yeast that normally lives on a dog's skin without causing problems. But when something compromises the dog's immunity or skin barrier—allergies, hormonal issues, moisture trapped in skin folds—the yeast multiplies out of control.[4]
The result? That unmistakable musty, stale smell. Greasy, inflamed skin. Constant itching. You'll often see it around the ears, lips, paws, and under the tail—anywhere warm and moist. Breeds with skin folds (Bulldogs, Shar Peis) or floppy ears (Cocker Spaniels, Basset Hounds) are particularly prone.
Ringworm isn't actually a worm—it's a fungal infection caused by dermatophytes like Microsporum canis, Microsporum gypseum, and Trichophyton mentagrophytes. These fungi invade the hair shafts and skin, causing circular patches of hair loss with scaly, crusty borders.[1]
Here's what matters for groomers: ringworm is zoonotic, meaning it can spread to humans. If you're grooming a dog with ringworm and you're not careful with hygiene and disinfection, you or your other canine clients could catch it.
Fungal spores can survive for months in the environment. This means that treating the dog alone isn't enough—vets will also advise clients to disinfect the dog's environment thoroughly.[5]
For you as a groomer, this means rigorous biosecurity. After grooming a dog with a confirmed or suspected fungal infection:
Oral ketoconazole carries a significant risk of liver toxicity (hepatotoxicity), which is why it requires strict veterinary supervision and monitoring. This isn't something groomers need to manage directly, but understanding the risks helps explain why vets are so cautious with this drug.
Ketoconazole is strictly contraindicated (absolutely not allowed) in dogs with liver failure. For dogs with healthy livers, vets must monitor liver function closely during long-term treatment, usually with regular blood tests.[6]
Warning signs of liver problems that might prompt a vet to stop treatment immediately include:
Even when the liver is fine, dogs on ketoconazole often experience gastrointestinal upset—nausea, vomiting, diarrhoea, and loss of appetite. Vets usually recommend giving the tablets with food (ideally something fatty like cheese or butter) to reduce these effects and improve absorption.[1]
Ketoconazole interferes with the production of steroid hormones, including testosterone and cortisol. This can cause temporary infertility in male dogs, which is why vets generally avoid using it in breeding males. It's also not recommended during pregnancy due to potential risks to developing puppies.[7]
Ketoconazole inhibits an enzyme system called cytochrome P450, which means it can dangerously increase levels of many other medications. This is a major concern that vets have to manage carefully.[6]
Critical interactions include:
This is another reason why ketoconazole is prescription-only and why owners must tell their vet about every medication, supplement, or herbal remedy their dog is taking.
This section is for information only—groomers must never dose or administer prescription medications. Understanding how vets prescribe ketoconazole helps you appreciate why strict vet supervision is essential.
Vets prescribe ketoconazole based on the dog's weight, typically around 10 mg per kilogram of body weight daily. Fungiconazol tablets come in 200 mg and 400 mg strengths and are scored so they can be split into halves or quarters for accurate dosing.[1]
Ketoconazole tablets should be given with food—ideally with a fatty meal like cheese or butter—to maximise absorption and reduce stomach upset. The tablets are flavoured to make them more palatable to dogs.
Treatment often lasts several weeks. The full course must be completed even after symptoms clear, to achieve a proper cure and prevent resistance. Owners should never stop treatment early or skip doses—if a dose is missed, they should skip it and continue the regular schedule rather than doubling up.[1]
Ketoconazole is also available in topical forms—shampoos, creams, and gels—which carry far less risk than oral tablets. This is where groomers might actually use ketoconazole, but only when a vet has prescribed it.
Vets sometimes prescribe human Nizoral 2% shampoo off-label for dogs. The critical factor here is contact time—ketoconazole shampoo needs at least 10 minutes on the skin before rinsing to be effective.[8]
If a client brings their dog to you with a vet prescription for medicated shampoo, you must:
Topical ketoconazole is much safer than oral because very little gets absorbed into the bloodstream. Side effects are usually limited to local irritation, redness, or temporary changes in coat colour. The risk of liver toxicity from shampoo alone is minimal.[9]
Vets now have safer alternatives to oral ketoconazole, particularly for long-term treatment. Understanding these options helps you answer client questions and refer appropriately.
Here's a quick comparison of the main antifungal treatments available in the UK:
| Product | Active Ingredient | Status | Best For |
|---|---|---|---|
| Fungiconazol (Oral) | Ketoconazole | POM-V (Prescription Only) | Systemic fungal infections (yeast, ringworm) under vet supervision |
| Malaseb (Topical) | Miconazole + Chlorhexidine | POM-V (Prescription Only) | Seborrhoeic dermatitis, ringworm (topical treatment) |
| Malabeze (Topical) | Chloroxylenol + Salicylic Acid | Non-Prescription | Routine management of yeast-prone dogs (groomer-friendly) |
| Human Nizoral (Topical) | 2% Ketoconazole | Off-Label (Vet Prescribed) | Topical yeast treatment (10-minute contact time required) |
Modern vets often prefer newer antifungal drugs that are safer for prolonged use:
Malaseb is a prescription antibacterial and antifungal shampoo (POM-V status) used for seborrhoeic dermatitis and ringworm in dogs. It contains miconazole (an antifungal) and chlorhexidine (antibacterial), and it's been a trusted treatment for decades.[11]
Like ketoconazole shampoo, proper contact time is essential—though Malaseb's contact time is specified by the vet. You can only use it when prescribed by a vet for that specific dog.
Malabeze shampoo is a professional medicated shampoo that doesn't require a prescription. It contains chloroxylenol, salicylic acid, and sodium thiosulphate, which help control surface oils and support dogs prone to recurrent yeast issues.[12]
Malabeze requires only a 5-minute contact time, making it more practical for grooming salon use. However, it's not a substitute for prescription antifungals when a dog has an active infection. If symptoms persist after about three weeks of use, advise the client to see their vet.
Clients sometimes ask about apple cider vinegar rinses or coconut oil for yeast infections. The truth? These home remedies are generally ineffective for established or widespread fungal infections.
Regular bathing helps control surface oils and yeast to some degree, but it won't cure an infection that's already taken hold. If a dog has symptoms of a fungal infection, they need proper veterinary diagnosis and treatment—not DIY solutions from the internet.
Your job is to observe, document, and refer—not to diagnose or treat. This approach protects you legally, keeps dogs safe, and maintains your professional reputation.
Understanding ketoconazole, its risks, and the regulatory framework around it makes you a more knowledgeable and valuable professional. You're not a vet, but you're often the first person to spot problems—and that early detection can make all the difference to a dog's comfort and recovery.
No, you cannot legally obtain Fungiconazol without a valid veterinary prescription. Oral ketoconazole for dogs is classified as POM-V (Prescription Only Medicine – Veterinary) in the UK, which means it can only be supplied on a written prescription from a vet registered with the Royal College of Veterinary Surgeons. The prescription must be signed, dated, and is valid for six months. This strict regulation exists because ketoconazole carries significant risks, including liver toxicity and dangerous drug interactions, which require veterinary supervision and monitoring.
The most serious side effect of oral ketoconazole is liver toxicity (hepatotoxicity), which is why vets monitor liver function during long-term treatment. Signs of liver problems include jaundice (yellowing of gums or eyes), severe vomiting, complete loss of appetite, and extreme lethargy. Common side effects include nausea, vomiting, diarrhoea, and reduced appetite—vets usually recommend giving tablets with fatty food to reduce these effects. Ketoconazole also interferes with hormone production, potentially causing temporary infertility in male dogs, and it's not recommended during pregnancy. The drug can interact dangerously with many other medications, particularly antacids, immunosuppressants, and certain parasite treatments.
Dog groomers can only use ketoconazole shampoo when it has been specifically prescribed by a vet for that individual dog, and only according to the vet's precise instructions. If a client brings their dog with a vet prescription for medicated shampoo, groomers must follow the instructions exactly—particularly the critical 10-minute contact time required for ketoconazole shampoo to be effective. Groomers cannot recommend, supply, or use prescription medicated shampoos without vet authorisation. For general salon use without prescription, groomers can consider non-prescription professional products like Malabeze shampoo, but should refer clients to their vet if symptoms persist after approximately three weeks.
Vets prescribe oral ketoconazole primarily to treat yeast dermatitis caused by Malassezia pachydermatis and ringworm (dermatophytosis) caused by fungi like Microsporum canis, Microsporum gypseum, and Trichophyton mentagrophytes. Malassezia yeast infections typically cause that distinctive musty smell, greasy inflamed skin, and intense itching, particularly in warm moist areas like ears, paws, and skin folds. Ringworm causes circular patches of hair loss with scaly, crusty borders and is zoonotic (can spread to humans). Effective treatment requires addressing both the infection itself and environmental contamination, as fungal spores can survive for months in the environment.
Yes, modern vets often prefer itraconazole or fluconazole over ketoconazole for long-term treatment because they have better safety profiles. Itraconazole is generally preferred for most fungal infections due to fewer side effects and less risk of liver toxicity, though it's typically more expensive. Fluconazole is chosen for infections affecting the nervous system because it crosses the blood-brain barrier more effectively. For topical treatment, vets may prescribe Malaseb shampoo (a POM-V prescription product containing miconazole and chlorhexidine). Groomers can use non-prescription Malabeze shampoo for routine management of dogs prone to yeast issues, though this is not a substitute for prescription treatment of active infections.
This guide is based on verified UK veterinary sources and regulatory information:
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