POM-V Prescription Required Companion Animal

Rapidexon 2 mg/ml Solution for Injection

Active ingredient: Dexamethasone

Form

Injection

Species

Cats Cattle Dogs Horses Pigs

Manufacturer

Eurovet Animal Health B.V.

VMD MA No.

16849/3012

What it's used for

In cattle: Treatment of primary ketosis (acetonaemia). Induction of parturition In horses: Treatment of arthritis, bursitis or tenosynovitis.

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 Dexamethasone

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

Rapidexon 2 mg/ml Solution for Injection — SPC Details

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

In cattle:
Treatment of primary ketosis (acetonaemia).
Induction of parturition
In horses:
Treatment of arthritis, bursitis or tenosynovitis.

Cattle, pigs, dogs and cats: Intramuscular use.
For the treatment of inflammatory or allergic conditions the following average doses are
advised. However the actual dose used should be determined by the severity of the signs
and the length of time for which they have been present.
SpeciesDosageHorses, cattle, pigs0.06 mg/kg body weight corresponding to 1.5 ml/50
kg
Dogs, cats0.1 mg/kg body weight corresponding to 0.5 ml/10
kg
For the treatment of primary ketosis in cattle (acetonaemia)
0.02 to 0.04 mg/kg body weight corresponding to 5-10 ml per cow given by intramuscular
injection is advocated dependent on the size of the cow and the duration of the signs. Care
should be taken not to overdose Channel Island breeds. Larger doses will be required if
the signs have been present for some time or if relapsed animals are being treated.
For the induction of parturition
0.04 mg/kg body weight corresponding to 10 ml per cow as a single intramuscular injection
after day 270 of pregnancy.
Parturition will normally occur within 48-72 hours.
For the treatment of arthritis, bursitis or tenosynovitis by single intra-articular, intrabursal or
local injection in the horse
Dosage 1-5 ml
These quantities are not specific and are quoted purely as a guide. Injections into joint
spaces or bursae should be preceded by the removal of an equivalent volume of synovial
fluid. Strict asepsis is essential.
To measure small volumes of less than 1 ml a suitably graduated syringe should be used
to ensure accurate administration of the correct dose.

Except in emergency situations, do not use in animals suffering from diabetes mellitus,
renal insufficiency, cardiac insufficiency, hyperadrenocorticism, or osteoporosis.
Do not use in viral infections during the viraemic stage or in cases of systemic mycotic
infections.
Do not use in animals suffering from gastrointestinal or corneal ulcers, or demodicosis.
Do not administer intra-articularly where there is evidence of fractures, bacterial joint
infections and aseptic bone necrosis.
Do not use in cases of hypersensitivity to the active substance, to corticosteroids or to any
of the excipients.
Refer to section 3.7.

Horses, cattle, pigs, dogs and cats:
After systemic administration and particularly during early stages of therapy.
Upon long-term use.
Transient.
With increased serum hepatic enzymes.
Increased risk of acute pancreatitis.
Involving significant alteration of fat, carbohydrate, protein and mineral metabolism, e.g.,
redistribution of body fat, muscle weakness and wastage and osteoporosis may result.
In the presence of bacterial infection, antibacterial drug cover is usually required when
steroids are used. In the presence of viral infections, steroids may worsen or hasten the
progress of the disease.
May be exacerbated in patients given non-steroidal anti-inflammatory drugs and in
animals with spinal cord trauma.
Corticosteroids are known to exert a wide range of side-effects. Whilst single high doses
are generally well tolerated, they may induce severe adverse reactions with long term use
and when esters possessing a long duration of action are administered. Dosage in
medium to long term use should therefore generally be kept to the minimum necessary to
control clinical signs.
During therapy effective doses suppress the hypothalamo-pituitreal adrenal axis. Following
cessation of treatment, signs of adrenal insufficiency extending to adrenocortical atrophy
can arise and this may render the animal unable to deal adequately with stressful
situations. Consideration should therefore be given to means of minimising problems of
adrenal insufficiency following the withdrawal of treatment (for further information see
standard texts).
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 also the package leaflet for
respective contact details.
Very rare (<1 animal /
10,000 animals treated,
including isolated reports):
Polydipsia
, polyphagia
Polyuria
Hypokalaemia
, changes in blood biochemical and
haematological parameters, hyperglycaemia
Hepatomegaly
Pancreatitis
Laminitis
Undetermined frequency
(cannot be estimated from
the available data)
Iatrogenic hyperadrenocorticism (Cushing’s disease)
Sodium retention
, water retention
Cutaneous calcinosis
Delayed wound healing, weakened resistance to or
exacerbation of existing infections
Gastrointestinal ulceration
Retained placenta, metritis, subfertility
Milk production decrease

None.

Special precautions for safe use in the target species:
If the veterinary medicinal product is used for induction of parturition in cattle, then a high
incidence of retained placentae may be experienced and possible subsequent metritis
and/or subfertility. Response to long-term therapy should be monitored at regular intervals
by a veterinary surgeon.
Use of corticosteroids in horses has been reported to induce laminitis. Therefore horses
treated with such preparations should be monitored frequently during the treatment period.
Because of the pharmacological properties of the active ingredient, special care should be
taken when the veterinary medicinal product is used in animals with a weakened immune
system.
Except in cases of acetonaemia and induction of the parturition, corticoid administration is
to induce an improvement in clinical signs rather than a cure. The underlying disease
should be further investigated. When treating groups of animals, use a draw-off needle to
avoid excessive broaching of the stopper.
Following intra-articular administration, use of the joint should be minimized for one month
and surgery on the joint should not be performed within eight weeks of use of this route of
administration.
Only the 25 ml vial should be used to treat cats, dogs and small piglets to prevent
excessive puncturing of the closure.
See section

Concurrent use with non-steroidal anti-inflammatory drugs may exacerbate gastrointestinal
tract ulceration.
Because corticosteroids can reduce the immunoresponse to vaccination, dexamethasone
should not be used in combination with vaccines or within two weeks after vaccination.
Administration of dexamethasone may induce hypokalaemia and hence increase the risk
of toxicity from cardiac glycosides. The risk of hypokalaemia may be increased if
dexamethasone is administered together with potassium depleting diuretics.
Concurrent use with anticholinestaerase may lead to increased muscle weakness in
patients with myasthenia gravis.
Glucocorticoids antagonise the effects of insulin.
Concurrent use with phenobarbital, phenytoin and rifampicin can reduce the effects of
dexamethason.

Do not store above 25 C. Do not freeze. Keep the vial in the outer carton.

Cattle Meat and offal: 8 days
Milk: 72 hours
Pigs Meat and offal: 2 days
Horses Meat and offal: 8 days.
Not authorised for use in horses producing milk for human consumption.

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.