Pentosan Polysulfate Sodium
Linear polymers of beta-1->4-linked xylose sulfated at the 2- and 3- positions
Also known as: PPS · Cartrophen-Vet · Elmiron · Pentosan Equine · pentosan polysulphate sodium · PZ-68 · sodium xylanpolysulphate · SP-54 · Fibrase · Fibrezym · Fibrocid · Hemoclar · Polyanion · Thrombocid
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Osteoarthritis (High loading dose for treatment of OA signs of pain, lameness and stiffness) | 20 mg/kg PO twice weekly for 5 weeks | PO | twice weekly | 5 weeks | 🌎 NA |
| Osteoarthritis (Medium Loading dose for management of OA after joint surgery) | 10 mg/kg PO once weekly for 12 weeks | PO | once weekly | 12 weeks | 🌎 NA |
| Osteoarthritis (Maintenance dose) | 10 mg/kg once weekly for 4 weeks as needed | PO | once weekly | 4 weeks | 🌎 NA |
| Osteoarthritis | 3 mg/kg IM or SC on four occasions with an interval of 5-7 days between injections | IM/SC | q5-7d | 4 doses | 🌎 NA |
- Osteoarthritis (High loading dose for treatment of OA signs of pain, lameness and stiffness): Always give on an empty stomach.
- Osteoarthritis (Medium Loading dose for management of OA after joint surgery): Always give on an empty stomach.
- Osteoarthritis (Maintenance dose): Always give on an empty stomach.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Persistent or recurrent FLUTD | 2-16 mg/kg PO q12h | PO | q12h | — | 🌎 NA |
| Persistent or recurrent FLUTD | 8 mg/kg PO q12h | PO | q12h | — | 🌎 NA |
- Persistent or recurrent FLUTD: Recent studies have not shown any statistical benefit.
- Persistent or recurrent FLUTD: Recent studies have not shown any statistical benefit.
Horses
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Osteoarthritis | 3 mg/kg IM on four occasions with an interval of 7 days between injections. | IM | q7d | 4 doses | 🌎 NA |
| Osteoarthritis | Inject mixture back into joint | Intra-articular | Once | — | 🌎 NA |
- Osteoarthritis: Prepare site as for surgery. Avoid iodine based skin preps; use neutral soapless cleanser. Withdraw ~1 mL synovial fluid, mix with pentosan in syringe, inject back. Firmly bandage and confine for 3-4 hours. Rest horse for 2 weeks, follow with 2 weeks graded walking.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Pentosan Polysulfate Sodium (PPS) is a semi-synthetic, heparin-like macromolecular carbohydrate derivative derived from Beechwood hemicellulose. It is primarily utilized in veterinary medicine as a Disease-Modifying Osteoarthritis Drug (DMOAD) and as an adjunctive therapy for lower urinary tract conditions.
Key clinical applications include:
- Osteoarthritis (OA): Used in dogs, cats, and horses to improve joint function, reduce inflammation, and promote cartilage health.
- Feline Idiopathic Lower Urinary Tract Disease (FLUTD) / Interstitial Cystitis: Used off-label to help restore the protective glycosaminoglycan (GAG) layer of the bladder urothelium, though clinical efficacy for short-term acute flare-ups is not well-documented.
Clinical Pearl: While structurally related to heparin, its anticoagulant activity is significantly weaker (approximately 1/15th that of heparin). However, caution is still warranted in patients with bleeding disorders or those undergoing surgery.
Mechanism of action
Pentosan polysulfate sodium exhibits multiple pharmacological effects depending on the target tissue:
- Osteoarthritis (Disease-Modifying Effects):
- Inhibits catabolic enzymes: Downregulates matrix metalloproteinases (MMPs) and aggrecanases that degrade articular cartilage.
- Stimulates matrix synthesis: Promotes the synthesis of hyaluronic acid by synovial fibroblasts and preserves proteoglycan content within the cartilage matrix.
- Improves microcirculation: Its mild anticoagulant, fibrinolytic, and hypolipidemic properties help mobilize thrombi and lipid deposits in subchondral blood vessels, thereby increasing synovial blood flow and nutrition to the joint.
- Interstitial Cystitis / FLUTD:
- Urothelial Protection: Excreted partially unchanged in the urine, PPS adheres to the mucosal membranes of the bladder wall. It acts as a synthetic glycosaminoglycan (GAG) buffer, preventing irritating urinary solutes and toxins from reaching and damaging the underlying transitional epithelial cells.
- Analgesia: Provides mild local analgesic and anti-inflammatory effects within the bladder wall.
Safety & warnings
Contraindications
- Known hypersensitivity to pentosan polysulfate sodium
- Patients with active bleeding disorders
- Use with caution prior to surgery
Adverse effects
- Vomiting
- Anorexia
- Lethargy
- Mild depression
- Bleeding or prolonged coagulation times (dose-dependent increase in PTT in horses)
- Transient increases in liver enzymes (reported in humans)
Precautions
Bleeding Risk: Because pentosan has mild anticoagulant properties, bleeding is possible in any species. Use with extreme caution in animals receiving other drugs that affect coagulation or those undergoing stressful exercise or surgery.
- Oral Administration in Cats: Dosing twice daily can be stressful for both the cat and the owner.
- Surgical Procedures: Consider withholding treatment prior to major surgical interventions due to the potential for increased surgical bleeding.
Drug interactions
May increase the risk of bleeding due to concurrent effects on coagulation and platelet function; use cautiously.
Increased risk of bleeding due to combined anticoagulant and antiplatelet effects.
Additive anticoagulant effects; increased risk of hemorrhage.
Monitoring
- Clinical efficacy (improvement in lameness/mobility for OA, or reduction in urinary signs for FLUTD)
- Signs of bleeding or bruising
- Intra-articular bleeding (when administered directly into joints)
Pharmacokinetics
Absorption
In rats, 10-20% of the calcium derivative is absorbed orally. In humans, only about 3% of an oral dose of pentosan polysulfate sodium is absorbed.
Distribution
Distributes primarily to the uroepithelium of the genitourinary tract. Smaller concentrations are found in the liver, spleen, lung, skin, bone marrow, and periosteum.
Metabolism
About two-thirds of absorbed drug is desulfated in the liver and spleen within one hour.
Elimination
About 3.5% of the absorbed drug is excreted into the urine.
Overdose
Information regarding overdoses is limited.
- Potential Signs: Overdoses could potentially cause bleeding, thrombocytopenia, gastrointestinal distress, and liver function abnormalities.
- Treatment: Treatment recommendations are basically supportive in nature. If an acute oral overdose occurs, consider standard protocols for drug removal from the gut (e.g., emesis, activated charcoal) if performed promptly.
Available products
Formulations
- Oral capsules
- Injectable solution (IM, SC, Intra-articular)
Veterinary
- Cartrophen-Vet Oral Capsules: 100 mg (pentosan polysulfate calcium) - Not available in USA
- Pentosan 100 Injection: 100 mg/mL - Not available in USA
- Cartrophen-Vet Injection: 100 mg/mL - Not available in USA
- Pentosan Equine Injection: 250 mg/mL - Not available in USA
Human-labeled
- Elmiron Oral Capsules: 100 mg
Regulatory status
No regulatory data for: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Unless otherwise labeled, store oral pentosan products at controlled room temperature (15-30°C; 59-86°F). Injectable pentosan products should be stored under refrigeration and protected from light.
Client information
For Pet Owners:
- Purpose: This medication is used to help manage joint pain and inflammation in arthritis, or to help soothe the bladder lining in cats with chronic urinary tract issues.
- Administration:
- Give on an empty stomach to ensure the best absorption.
- For cats taking the human capsule form, the dose is often half a capsule. Your veterinarian may instruct you to empty half the powder into a new, empty gelatin capsule to make dosing easier.
- What to Watch For: Because this drug has mild blood-thinning effects, watch for any unusual bleeding, bruising, or dark/tarry stools. Contact your veterinarian if you notice these signs.
- Side Effects: Mild stomach upset (vomiting, loss of appetite) or lethargy can occasionally occur. Let your vet know if these persist.
- Safety: Do not give your pet any over-the-counter pain medications (like aspirin) without consulting your veterinarian, as this can increase the risk of bleeding.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.