pentosan, Elmiron

Pharmacy Author:
Medical and Pharmacy Editor:

GENERIC NAME: pentosan


DRUG CLASS AND MECHANISM: Pentosan is a semi-synthetic (man-made) drug that resembles the anticoagulant ("blood thinner") heparin and is used for treating the symptoms of interstitial cystitis. Interstitial cystitis is a condition, usually of unknown cause, in which there is inflammation of the urinary bladder that most frequently causes pelvic pain and frequent urination. The exact mechanism whereby pentosan reduces the symptoms of interstitial cystitis also is unknown; however, scientists believe that pentosan may coat the lining of the bladder and prevent irritating substances in the urine from reaching the cells of the lining. The FDA approved pentosan in September 1996.



PREPARATIONS: Capsules: 100 mg.

STORAGE: Pentosan should be stored at room temperature, between 15 C to 30 C (59 F to 86 F).

PRESCRIBED FOR: Pentosan is used for relieving bladder pain caused by interstitial cystitis.

DOSING: The recommended dose of pentosan is 100 mg three times daily (every 8 hours) taken at least one hour before or two hours after meals so that food does not retard its absorption. Patients should be evaluated after 3 months, and treatment may be continued for another three months if patients have not improved and they are tolerating pentosan.

DRUG INTERACTIONS: Pentosan resembles heparin and it affects the ability of blood to clot. Therefore, it can cause bleeding and if combined with other drugs that also cause bleeding (anticoagulants) the risk of bleeding may increase. Examples of drugs that cause bleeding include heparin, streptokinase, aspirin, nonsteroidal anti-inflammatory drugs (for example, ibuprofen), and warfarin (Coumadin).

PREGNANCY: Studies with pentosan have not been conducted in pregnant women.

NURSING MOTHERS: Studies of pentosan have not been conducted in nursing mothers.

SIDE EFFECTS: The most common side effects of pentosan are stomach upset, diarrhea, nausea, headache, rash, abdominal pain, hair loss and dizziness. Some patients may develop abnormalities of liver tests in the blood. Bleeding from the rectum and other areas also may occur.

Reference: FDA Prescribing Information

Medically Reviewed by a Doctor on 3/21/2013

Report Problems to the Food and Drug Administration

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Pill Finder Tool

Need help identifying pills and medications?
Use the pill identifier tool on RxList.

Back to Medications Index