Alosetron blocks the action of a chemical called serotonin in the intestines. This slows the movement of stools (bowel movements) through the intestines.

Alosetron is used to treat severe, chronic irritable bowel syndrome (IBS) in women with diarrhea as the main symptom for at least 6 months. Alosetron is given after other treatments have failed.

Alosetron is not a cure for irritable bowel syndrome. After you stop taking alosetron, your symptoms may return within 1 week.

Alosetron has not been shown to be effective in men with IBS.

Alosetron may also be used for purposes not listed in this medication guide.

Alosetron should be used only by women with severe irritable bowel syndrome and diarrhea as the main symptom.

Do not start taking alosetron if you are constipated. You also should not take alosetron if you take another medicine called fluvoxamine (Luvox).

Serious or fatal side effects on the stomach and intestines have occurred in some people taking alosetron. In rare cases, alosetron has caused severe constipation, or ischemic colitis (caused by reduced blood flow to the intestines).

Stop taking alosetron and call your doctor right away if you have: new or worsening constipation, stomach pain, bright or dark red blood in your stools, or bloody diarrhea. You may need to permanently discontinue alosetron if you have these side effects.

If you stop taking alosetron for any reason, do not start taking it again without your doctor's advice.

Do not start taking alosetron if you are constipated. Stop taking the medicine and call your doctor if you become constipated.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose. Use the medicine exactly as directed.

You may take alosetron with or without food.

Alosetron does not improve the symptoms of IBS for everyone. alosetron can help reduce stomach pain and discomfort, bowel urgency, and diarrhea. Some or all symptoms may improve within 1 to 2 weeks of treatment.

Stop taking alosetron and call your doctor if your IBS symptoms do not improve after 4 weeks of treatment.

If you stop taking alosetron for any reason, do not start taking it again without your doctor's advice.

Store at room temperature away from moisture, heat, and light.

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; may be increased up to 1 mg orally twice a day after 4 weeks of treatment.
Maximum dose: 2 mg/day

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

Use: 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

Do not take alosetron if you have ever had any of the following conditions:

• constipation (especially if it is your main IBS symptom);

• a history of severe or ongoing constipation;

• obstruction or perforation of your intestines;

• Crohn's disease, ulcerative colitis, or diverticulitis;

• blood clots, or circulation problems affecting your intestines;

• severe liver disease; or

• a condition for which you also take fluvoxamine (Luvox).

Tell your doctor if you are pregnant or breastfeeding.

If you breastfeed while taking alosetron, call your doctor if your baby shows signs of constipation or has bloody stools.

Alosetron is not approved for use by anyone younger than 18 years old.

Skip the missed dose and use your next dose at the regular time. Do not use two doses at one time.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from light, excess heat and moisture (not in the bathroom).

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

Unless your doctor tells you otherwise, continue your normal diet.

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Serious or fatal side effects on the stomach and intestines have occurred in some people taking alosetron. In rare cases, alosetron has caused severe constipation, or ischemic colitis (caused by reduced blood flow to the intestines).

Stop taking alosetron and call your doctor right away if you develop:

• new or worsening constipation;

• stomach pain;

• bright or dark red blood in your stools; or

• bloody diarrhea.

You may need to permanently discontinue alosetron if you have these side effects.

Older adults and those who are ill or debilitated may be more likely to have serious complications from constipation.

Common side effects of alosetron may include:

• constipation;

• nausea; or

• pain or discomfort in your stomach or intestines.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Sometimes it is not safe to use certain medications at the same time. Some drugs can affect your blood levels of other drugs you take, which may increase side effects or make the medications less effective.

Many drugs can affect alosetron, and some drugs should not be used at the same time. Tell your doctor about all your current medicines and any medicine you start or stop using. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed here.

Keep all appointments with your doctor.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.