POM-V Prescription Required

Pro Dynam Oral Powder 1 g Phenylbutazone Per Sachet

Active ingredient: Phenylbutazone

Form

Powder

Species

Horses

Manufacturer

Dechra Veterinary Products A/S

VMD MA No.

24883/4000

What it's used for

The product is indicated for the treatment of musculo-skeletal conditions where relief from pain and a reduction in the associated inflammation is required...

Full indications, dosage and side effects ↓

View official SPC (PDF)

The prescription itself has a price. See what practices near you charge for a consultation and the written prescription fee.

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

Fill it at a registered online retailer

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

Your prescription rights → VMD register of retailers →

Prescription required

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

Clinical information

Pro Dynam Oral Powder 1 g Phenylbutazone Per Sachet — SPC Details

Source: VMD Summary of Product Characteristics (SPC). Last updated 26 Mar 2026.

The product is indicated for the treatment of musculo-skeletal conditions where relief from pain
and a reduction in the associated inflammation is required e.g. in lameness associated with
osteoarthritic conditions, bursitis, laminitis and soft tissue inflammation, particularly where
continued mobility is considered desirable.
It is also of value in limiting post surgical inflammation, myositis and other soft tissue
inflammation.
Pro-Dynam can be used as an anti-pyretic where this is considered advisable e.g. in viral
respiratory infections.

Should be administered by mouth.
For each 450 kg (1000 lbs) bodyweight the following dosage guide should be used according to
individual response:
Day 1: Two sachets twice daily (equivalent to 4.4 mg/kg on each occasion).
Day 2-4: One sachet twice daily (equivalent to 2.2 mg/kg on each occasion) followed by one
sachet daily (2.2 mg/kg daily) or on alternate days as required.
If no response is evident after 4-5 days, discontinue treatment. Hay 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 Pro-Dynam.
For ease of administration Pro-Dynam may be mixed with a quantity of bran or oats.

Do not use in animals with known hypersensitivity to the active ingredient.
Use is contra-indicated 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 administer other NSAIDs concurrently or within 24 hours of each other.

In common with other NSAIDs that inhibit prostaglandin synthesis, there may be gastric and/or
renal intolerance. This is usually associated with overdosage and such events are rare. Recovery
is usual on cessation of treatment and following the initiation of supportive symptomatic
therapy (see 4.10 for further information).

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.
Some equestrian authorities regard phenylbutazone as a ‘prohibited substance’ within their
rules.

Revised: 30
th
April 2009
AN: 02557/2008

Special precautions for use in animals
Do not exceed the stated dose 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 may require careful clinical management.
Avoid use in any dehydrated, hypovolaemic or hypotensive animal as there is a potential risk of
increased renal toxicity.
NSAID’S can cause inhibition of phagocytosis and hence in the treatment of inflammatory
conditions associated with bacterial infections, appropriate concurrent antimicrobial therapy
should be instigated.
Special precautions to be taken by the person administering the veterinary medicinal
product to animals
Wash hands after use.
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 the event of accidental inhalation or ingestion seek medical advice and show the product
packaging.

Concurrent administration of potential nephrotoxic drugs should be avoided.
Phenylbutazone is extensively bound to plasma proteins. It may displace other drugs that are
highly protein bound e.g. some sulphonamides, 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 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 of other drugs
given concurrently may also be affected.

Not for use 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.

Revised: 30
th
April 2009
AN: 02557/2008
5.

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.