Skip to Content

Alosetron Dosage

Applies to the following strength(s): 0.5 mg ; 1 mg

The information at is not a substitute for medical advice. ALWAYS consult your doctor or pharmacist.

Usual Adult Dose for:

Additional dosage information:

Usual Adult Dose for Irritable Bowel Syndrome

-Initial dose: 0.5 mg orally twice a day
-Maintenance dose: 0.5 mg orally once or twice a day; can be increased up to 1 mg orally twice a day after 4 weeks of treatment.

-Due to the serious GI adverse reactions associated with this drug, treatment should be restricted to female patients for whom the benefit-to-risk balance is most favorable.

Use: For women with severe diarrhea-predominant irritable bowel syndrome (IBS) who have chronic IBS symptoms (generally lasting 6 months or longer), had anatomic or biochemical abnormalities of the gastrointestinal tract excluded, and have not responded adequately to conventional therapy.

Renal Dose Adjustments

No adjustment recommended.

Liver Dose Adjustments

-Mild or moderate hepatic impairment (Child-Pugh score 9 or less): Use with caution.
-Severe hepatic impairment (Child-Pugh score greater than 9): Contraindicated.

Dose Adjustments

-Reduce frequency of dose to 0.5 mg orally once a day if constipation occurs with initial dose level; immediately discontinue if constipation recurs at this lower dose.

-After 4 weeks of treatment: May increase dose up to 1 mg orally twice a day if current dosage well tolerated but IBS symptoms not adequately controlled; discontinue if IBS symptoms not controlled after 4 weeks of treatment at 1 mg orally twice a day.


US REMS: The US FDA requires a Risk Evaluation and Mitigation Strategy (REMS) for this drug. It includes a medication guide, elements to assure safe use, and an implementation system. For additional information:

-Infrequent but serious gastrointestinal adverse reactions have been reported with the use of this drug. These events (including ischemic colitis and serious complications of constipation) have resulted in hospitalization, and rarely, blood transfusion, surgery, and death.
-Only healthcare providers who have enrolled in the REMS program should prescribe this drug.
-This drug is indicated only for women with severe diarrhea-predominant irritable bowel syndrome (IBS) who have not responded adequately to conventional therapy.
-This drug should be discontinued immediately in patients who develop constipation or symptoms of ischemic colitis. Treatment should be permanently discontinued in patients with ischemic colitis, but it may be resumed in patients with resolved constipation on the advice of their prescriber.

Safety and efficacy have not been established in patients younger than 18 years. Use is not recommended in the pediatric population based upon the serious complications or constipation and ischemic colitis in adults.

Consult WARNINGS section for additional precautions.


Data not available

Other Comments

Administration Advice:
-Take with or without food.

-To prescribe this drug, physicians must be enrolled in the REMS program. The Prescriber Enrollment Form can be found at
-This drug may be dispensed only if the prescription has a sticker for the REMS program attached; No telephone, facsimile, or computerized prescriptions are permitted with this drug.
-Inhibition of the metabolic elimination and reduced first pass of other drugs might occur with overdoses of this drug.

Gastrointestinal: Signs/symptoms of constipation, serious complications of constipation, and ischemic colitis

Patient Advice:
-Do not drink alcohol while taking this drug.
-This drug is for women only; there has not been enough testing done to confirm that this drug works in men and children under age 18.