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pentosan (pen-toe-san)



Therapeutic: agents for interstitial cystitis

Pharmacologic: heparin-like compounds


Management symptoms (bladder pain/discomfort) of chronic interstitial cystitis (IC).


Adheres to uroepithelium, providing a protective barrier against irritating solutes in urine; has anticoagulant and fibrinolytic properties. Therapeutic Effects: ↓ pain and discomfort in chronic IC.

Adverse Reactions/Side Effects

CNS: dizziness, headache. EENT: epistaxis. GI: abdominal pain, diarrhea, dyspepsia, gum bleeding, ↑ liver enzymes, nausea, rectal bleeding. Derm: alopecia, ecchymosis, rash. Hemat: bleeding, ↑ bleeding time.


Examination and Evaluation

  • Assess for signs of bleeding and increased bleeding time, including bleeding gums, nosebleeds, and rectal bleeding. Notify physician if this drug causes increased bleeding.

  • Monitor signs of interstitial cystitis, including chronic pelvic pain, persistent urge to urinate, and painful sexual intercourse. Document whether this drug is successful in reducing these symptoms.

  • Assess dizziness that might affect gait, balance, and other functional activities (see Appendix C). Report balance problems and functional limitations to the physician, and caution the patient and family/caregivers to guard against falls and trauma.


  • Use caution with any physical interventions that could increase bleeding, including wound débridement, chest percussion, joint mobilization, and application of local heat.

Patient/Client-Related Instruction

  • Instruct patient to report other bothersome side effects such as severe or prolonged headache, skin reactions (rash, bruising, hair loss), or GI problems (nausea, diarrhea, abdominal pain, indigestion).


Absorption: 6% absorbed following oral administrations.

Distribution: Distributes into uroepithelium of the genitourinary tract with less found in liver, spleen, lung, skin, periosteum, and bone marrow.

Metabolism and Excretion: Metabolized by saturable enzyme systems in liver, spleen, and kidney. Majority (58–84%) excreted in feces as unchanged (unabsorbed drug). Metabolites of absorbed drug are renally excreted; minimal renal excretion of unchanged drug.

Half-life: 27 hr.

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PO within 4 wk–6 mo unknown unknown


Contraindicated in: Hypersensitivity.

Use Cautiously in: Underlying coagulopathy, concurrent medications that ↑ bleeding risk, history of aneurysms. Thrombocytopenia, hemophilia, GI ulceration/bleeding, polyps, diverticula; History of heparin-induced thrombocytopenia; risk of bleeding may be ↑ hepatic insufficiency; OB: Use in pregnancy only if clearly needed; Lactation: Use cautiously in breast-feeding women; Pedi: safe and effective use in children <16 yr has not been established.


Drug-Drug: Concurrent use of coumarin anticoagulants, heparins, t-PA, streptokinase, high-dose aspirin, or NSAIDs may ↑ risk of ...

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