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POM-V Prescription Required Companion Animal

Anarthron 100 mg/mL Solution for Injection for Dogs

Active ingredient: Pentosan Polysulphate Sodium

Form

Injection

Species

Dogs

Manufacturer

Arthropharm Europe Ltd

VMD MA No.

15519/3000

What it's used for

AN: 02816/2024 and 02960/2024

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 Pentosan Polysulphate Sodium

  1. 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. 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.

Prescription required

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

Clinical information

Anarthron 100 mg/mL Solution for Injection for Dogs — SPC Details

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

AN: 02816/2024 and 02960/2024
Dosage: 3mg pentosan polysulfate sodium/kg bodyweight (equivalent to
0.3ml/10kg bodyweight) on four occasions, with an interval of 5-7 days
between each administration.
Administration: By aseptic subcutaneous injection only of 0.3ml/10kg of
bodyweight. An appropriately graduated syringe must be used to allow
accurate administration of the required dose volume. This is particularly
important when injecting small volumes.
Each case should be assessed individually by the veterinarian and an
appropriate treatment program determined.
Do not use in the treatment of septic arthritis. In this case, appropriate
antimicrobial therapy should be instigated.
Do not use in dogs with advanced liver or kidney impairment, or evidence of
infection.
Do not use in dogs with blood disorders, coagulation disorders, bleeding or
malignancy (especially haemangiosarcoma).
Pentosan polysulfate sodium has an anticoagulant effect. Do not use during
the peri-operative period.
Do not use in the skeletally immature dog (i.e. dogs whose long bone growth
plates have not closed).
Dog
Very rare
(<1 animal / 10 000 animals
treated, including isolated
reports)
Emesis
1,2
, diarrhoea
1,2
Lethargy
1,2
, anorexia
1,2
Hypersensitivity reaction
Prolonged activated partial thrombin time
(APTT)
, prolonged thrombin time (TT)
Injection site reaction, injection site swelling
Undetermined frequency
(cannot be estimated from
the available data):
Bleeding disorder (e.g. nasal bleeding,
haemorrhagic diarrhoea, haematoma)
Due to a hypersensitivity reaction.
May require appropriate symptomatic treatment, including antihistamine
administration.
May persist for up to 24 hours after administration in healthy dogs. This very
rarely results in clinical effects, but because of the fibrinolytic action of
pentosan polysulfate sodium, the possibility of internal bleeding from a tumour
or vascular abnormality should be considered if signs develop. It is
recommended that the animal should be monitored for signs of blood loss and
treated appropriately.
Transient.
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 the national
competent authority via the national reporting system. See the package leaflet
for respective contact details.
A clinical effect may not be observed until after the second injection of the
course of treatment.

Special precautions for safe use in the target species:
Use with caution in dogs with history of pulmonary lacerations.
Caution is also recommended in cases of hepatic impairment.
Do not exceed the standard dose. Increasing the recommended dose may
result in exacerbation of stiffness and discomfort.
No more than 3 courses of 4 injections should be administered in a 12 month
period.
Special precautions to be taken by the person administering the veterinary
medicinal product to animals:
Care should be taken to avoid accidental self-injection.
Wash splashes from eyes and skin immediately with water.
Wash hands after use
Special precautions for the protection of the environment:
Not applicable.
AN: 02816/2024 and 02960/2024
interaction
NSAIDs and in particular aspirin should not be used in combination with
pentosan polysulfate sodium as they may affect thrombocyte adhesion and
potentiate the anticoagulant activity of the product.
Corticosteroids have been shown to be antagonistic to a number of actions of
pentosan polysulfate sodium. Furthermore, use of anti-inflammatory drugs
AN: 02816/2024 and 02960/2024
may result in a premature increase in the dog’s activity, which may interfere
with the therapeutic activity of the product.
Do not use concurrently with steroids or non-steroidal anti-inflammatory drugs,
including aspirin and phenylbutazone.
Do not use concurrently with heparin, warfarin or other anti-coagulants.
Do not store above 25 C.
Keep the vial in the outer carton in order to protect from light.
Not applicable.

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.

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