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Chanazone 1 g, Oral Powder for Horses

Active ingredient: Phenylbutazone

Form

Powder

Species

Horses

Manufacturer

Chanelle Pharmaceuticals Manufacturing Ltd

VMD MA No.

08749/4066

What it's used for

osteoarthritic conditions, bursitis, laminitis and soft tissue inflammation, particularly where continued mobility is considered desirable. Alleviation of...

Full indications, dosage and side effects ↓

View official SPC (PDF)

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Paying less for Phenylbutazone

1

Ask your vet for a written prescription

They must provide one on request. Under the CMA Order the fee is capped at £21 from 2027.
2

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The CMA found online pharmacies 50–60% cheaper than practice dispensing on common medicines — typically £200–£300 a year.

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Prescription required

Your vet must provide a written prescription on request. You can then purchase from any licensed online retailer.

Clinical information

Chanazone 1 g, Oral Powder for Horses — SPC Details

Source: VMD Summary of Product Characteristics (SPC). Last updated 27 Mar 2026.

osteoarthritic conditions, bursitis, laminitis and soft tissue inflammation, particularly where
continued mobility is considered desirable.
Alleviation of post surgical inflammation, myositis and other soft tissue inflammation.
The veterinary medicinal product can be used as an anti-pyretic where this is considered
advisable e.g. in viral respiratory infections.
AN: 02236/2024 & 02238/2024

The recommended dose rate is 4.4 – 8.8 mg/kg bodyweight per day.
The dosage should be adjusted according to the individual animal’s response, but the
following may be taken as a guide:
Horse (450 kg bodyweight):
Day 1: 4.4 mg phenylbutazone/kg bodyweight twice daily, (equivalent to two sachets or
10 g of the veterinary medicinal product twice daily).
Day 2-4: 2.2 mg phenylbutazone /kg bodyweight twice daily, (equivalent to one sachet or
5 g of the veterinary medicinal product twice daily) followed by 2.2 mg phenylbutazone
/kg bodyweight daily, (equivalent to one sachet or 5 g of the veterinary medicinal product
daily) or on alternate days as required.
If no response is evident after 4-5 days, discontinue treatment. Hay intake may delay the
absorption of phenylbutazone and so the onset of a clinical effect. It is advisable not to
administer hay immediately prior to, or during the administration of the veterinary
medicinal product.
AN: 02236/2024 & 02238/2024
For ease of administration the product may be mixed with a quantity of bran or oats
before each treatment.

Do not use in cases of hypersensitivity to the active substance or to any of the excipients.
Do not use in animals suffering from cardiac, hepatic or renal disease, where there is the
possibility of gastro-intestinal ulceration or bleeding or where there is evidence of a blood
dyscrasia.
Do not use in animals suffering from thyroid disease.
Do not use in animals with severe hypertonia.
Do not use in animals with lesions in the intestinal mucosa, caused by parasitic
infestations.

Horses:
Rare
(1 to 10 animals / 10,000 animals treated):
Digestive tract disorder
1,2
Renal disorder
Undetermined frequency
(cannot be estimated from the available
data)
Blood dyscrasia
In common with other NSAIDs that inhibit prostaglandin synthesis there may be gastric
and/or renal intolerance. This is usually associated with overdosage. Recovery is usual
on cessation of treatment and following the initiation of supportive symptomatic therapy
(see section 3.10 for further information).
Ponies are very sensitive to gastric ulceration with this veterinary medicinal product,
even at therapeutic doses (diarrhoea, ulceration in the mouth and hypoproteinaemia may
also be seen).
If adverse reactions occur, treatment should be discontinued and the advice of a
veterinarian should be sought.
Reporting adverse events is important. It allows continuous safety monitoring of a
veterinary medicinal product. Reports should be sent, preferably via a veterinarian, to
either the marketing authorisation holder or its local representative or the national
competent authority via the national reporting system. See the package leaflet for
respective contact details.

The clinical effects of phenylbutazone can be evident for at least three days following
cessation of therapy. This should be borne in mind when examining horses for
soundness.
The International Federation for Equestrian Sports (FEI) regards phenylbutazone as
prohibited substance in the context of a participation of the treated horse in equestrian
sport events. A horse, which is or has recently been under treatment with the product,
might not be allowed to participate in sport events. Please refer to recommendations of
the FEI, national laws and national association rules for withdrawal times prior to
competition.

Special precautions for safe use in the target species:
Do not exceed the stated dose of 8.8 mg/kg/day as the therapeutic index of
phenylbutazone is low.
Use in any animal less than 6 weeks of age or in aged animals may involve additional
risk. If such use cannot be avoided animals require careful clinical management.
Avoid use in any dehydrated, hypovolaemic or hypotensive animal as there is a potential
risk of increased renal toxicity. Keep water readily available during the treatment period
to avoid dehydration.
NSAIDs can cause inhibition of phagocytosis and hence in the treatment of inflammatory
conditions associated with bacterial infections, appropriate concurrent antimicrobial
therapy should be considered.
Special precautions to be taken by the person administering the veterinary medicinal
product to animals:
This veterinary medicinal product may cause hypersensitivity (allergic) reactions in those
sensitized to phenylbutazone, either via skin contact or accidental inhalation.
People with known hypersensitivity to phenylbutazone, or any of the excipients, should
avoid contact with this veterinary medicinal product.
AN: 02236/2024 & 02238/2024
If you develop symptoms following exposure, such as skin rash, you should seek medical
advice and show the doctor this warning. Swelling of the face, lips or eyes, or difficulty
breathing, are more serious symptoms and require urgent medical attention.
This veterinary medicinal product can be irritating to the skin and the eyes. Avoid contact
with the eyes. In case of accidental eye contact, irrigate eyes with plenty of clean water.
If irritation persists seek medical advice.
Care should be taken to avoid inhaling or ingesting the powder. In case of accidental
inhaling or ingestion, seek medical advice immediately and show the package leaflet or
the label to the physician. Wash any exposed skin and hands after use.
Special precautions for the protection of the environment:
Not applicable.

Do not administer other NSAIDs concurrently or within 24 hours of each other.
Concurrent administration of potential nephrotoxic drugs should be avoided.
Phenylbutazone induces hepatic microsomal enzyme activity.
There is a potential risk of increased renal toxicity after concurrent administration of
aminoglycosides.
Concomitant use of glucocorticoids, other NSAIDs or anticoagulants increase adverse
effects of phenylbutazone.
Therapeutic efficacy of diuretics may be reduced when used in combination with
phenylbutazone-containing products.
Phenylbutazone is extensively bound to plasma proteins. It may displace other drugs that
are highly protein bound, e.g. some sulphonomides, warfarin or it may itself be displaced
to produce an increase in non-bound pharmacologically active concentrations, which can
lead to toxic effects.
Concurrent therapy with other therapeutic agents should be undertaken with caution due
to the risk of metabolic interactions. Phenylbutazone may interfere with the metabolism of
other drugs, e.g. warfarin, barbiturates with resultant toxicity.
There is evidence to indicate that the pharmacokinetics of penicillin and gentamicin
products may be affected by concurrent administration of products containing
phenylbutazone, with a possible reduction of therapeutic efficacy, since tissue
penetration may be reduced. The distribution in other drugs given concurrently may also
be affected.

This veterinary medicinal product does not require any special storage conditions.

Not to be used in horses intended for human consumption.
Treated horses may never be slaughtered for human consumption.
The horse must have been declared as not intended for human consumption under
national horse passport legislation.

This information is sourced from the official Summary of Product Characteristics (SPC) published by the Veterinary Medicines Directorate (VMD). It is provided for informational purposes only and does not replace professional veterinary advice. Always consult your vet before administering any medication.