Pentosan Polysulfate
Pentosan polysulfate is a semisynthetic sulfated polysaccharide used for clinical signs associated with noninfectious osteoarthritis. Veterinary products are available for dogs or horses in different regions. It has heparin-like pharmacologic properties and effects on joint inflammatory and matrix pathways. Sodium and calcium formulations have distinct product and evidence bases.
Group
Disease-modifying osteoarthritis agent
Mechanism of Action
Pentosan’s joint effects are incompletely defined but may include stimulation of hyaluronic-acid and glycosaminoglycan synthesis, inhibition of cartilage-degrading enzymes and modulation of cytokine activity. These actions may support synovial function and reduce inflammation-associated cartilage breakdown. Anticoagulant and fibrinolytic effects also occur. A proposed interaction with the bladder’s mucosal surface provides a separate rationale for empirical cystitis use; this mechanism remains incompletely characterized.
Dose Rates
Dogs
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Noninfectious osteoarthritis | 3 mg/kg | SC | Every 120–168 h | Do not use in: Skeletal immaturity, Bleeding disorder, Septic arthritis, Perioperative period; Four injections only, separated by 5–7 days; no more than three courses in 12 months. Skeletally mature dogs only. |
| Noninfectious osteoarthritis | 3 mg/kg | IM | Every 120–168 h | Pentosan 100 sodium injection course: four administrations. This does not change Cartrophen’s separately verified SC-only route. |
| Oral calcium-pentosan loading and maintenance | Reference only | PO | Calcium salt courses: 20 mg/kg twice weekly for 5 weeks, or 10 mg/kg weekly for 12 weeks; a maintenance course uses 10 mg/kg weekly for 4 weeks as needed. Give on an empty stomach. These calcium-salt amounts are not interchangeable with sodium-salt strengths. |
Cats
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Persistent or recurrent idiopathic lower urinary tract disease | 2–16 mg/kg | PO | Every 12 h | Pentosan polysulfate sodium; alternative empirical regimen. Studies have not shown benefit for acute short-term disease; not a treatment for urinary obstruction. |
| Persistent or recurrent idiopathic lower urinary tract disease | 8 mg/kg | PO | Every 12 h | Pentosan polysulfate sodium; alternative empirical regimen. Studies have not shown benefit for acute short-term disease; not a treatment for urinary obstruction. |
| Alternative fixed sodium-pentosan cystitis regimen | Reference only | PO | Every 12 h | A 50 mg total amount twice daily has been described using half the contents of a 100 mg sodium-pentosan capsule. Efficacy for idiopathic lower urinary tract disease is uncertain; it does not relieve obstruction. |
Horses
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Noninfectious osteoarthritis | 3 mg/kg | IM | Every 168 h | Four injections, one week apart; use a suitable equine pentosan sodium product. |
Indications
- Treatment of clinical signs associated with noninfectious osteoarthritis in skeletally mature dogs using a corresponding veterinary product.
- Control of clinical signs associated with osteoarthritis in horses using an appropriate equine preparation.
- Empirical adjunctive treatment of selected persistent or recurrent feline idiopathic cystitis, with clinical benefit unestablished.
Contraindications
- Septic arthritis
- Skeletal immaturity
- Bleeding or coagulation disorder
- Advanced renal or hepatic impairment
- Perioperative period
- Malignancy, especially hemangiosarcoma
Interactions
- Do not combine Cartrophen with NSAIDs, corticosteroids, heparin, warfarin or other anticoagulants.
Adverse effects
- Vomiting or diarrhea
- Lethargy
- Injection-site swelling
- Bleeding
Toxicity
Overdose increases bleeding and hepatocellular injury risk; stop and provide hospital monitoring and supportive treatment.
Preparations
| Preparation | Form | Strength | Route |
|---|---|---|---|
| Cartrophen Vet injection 100 mg/mL Pentosan polysulfate sodium. Four-injection course; not an unrestricted repeating injection. | Injection | 100 mg / mL | SC |
| Pentosan 100 sodium injection 100 mg/mL Four-dose dog course; distinct product from SC-only Cartrophen. | Injection | 100 mg / mL | IM, SC |
| Pentosan Equine sodium injection 250 mg/mL Four weekly equine IM injections. No numeric intra-articular dose established from the cited instructions. | Injection | 250 mg / mL | IM |
| Elmiron sodium-pentosan capsules 100 mg Pentosan polysulfate sodium, not calcium. | Capsule | 100 mg / capsule | PO |
| Cartrophen-Vet oral calcium-pentosan capsules 100 mg Calcium salt. Does not match the sodium-based parent calculation ingredient; retain as a distinct readable product. | Capsule | 100 mg / capsule | PO |
Monitoring and Administration
Assess coagulation risk and monitor for blood loss. No more than three four-injection courses in 12 months.
Avoid use in pregnant bitches and at parturition. Do not mix in the same syringe with other drugs.
For Cartrophen 100 mg/mL, store below 25°C protected from light and use within 3 months of opening.
Intra-articular equine technique has been described, but an actual administered dose is not stated. Such treatment requires strict asepsis and monitoring for joint bleeding; a dose cannot be inferred from the 250 mg/mL vial.
Give oral products on an empty stomach. Product storage is formulation-specific: keep the previously verified Cartrophen injection below 25°C rather than replacing its instructions with a general injectable refrigeration statement.