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Generic Name: Alosetron (a LOE se tron)
Brand Name: Lotronex

Medically reviewed by Last updated on Sep 4, 2020.


  • Very bad GI (gastrointestinal) side effects have rarely happened in people taking alosetron. Sometimes, these have led to a hospital stay and, rarely, blood transfusions, surgery, and death. Call your doctor right away if you get constipation, new or worse stomach pain, rectal bleeding, or blood in your stools.
  • This medicine is only approved for some women who have tried other drugs and the drugs have not worked. Talk with your doctor.

Uses of Alosetron:

What do I need to tell my doctor BEFORE I take Alosetron?

  • If you have an allergy to alosetron or any other part of alosetron.
  • If you are allergic to alosetron; any part of alosetron; or any other drugs, foods, or substances. Tell your doctor about the allergy and what signs you had.
  • If you have constipation.
  • If you have ever had any of these health problems: Blood clots or blood-clotting problems, blood flow problems in the bowel, bowel block, Crohn's disease, diverticulitis, hole in the GI (gastrointestinal) tract, ischemic or ulcerative colitis, a large colon, liver problems, long-term or very bad constipation, or narrowing or growths in the bowel.
  • If you are taking fluvoxamine.
  • If you are taking any of these drugs: Cimetidine, ciprofloxacin, delafloxacin, fluvoxamine, gemifloxacin, levofloxacin, moxifloxacin, norfloxacin, or ofloxacin.
  • If the patient is a child. Do not give alosetron to a child.

This is not a list of all drugs or health problems that interact with alosetron.

Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take alosetron with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

What are some things I need to know or do while I take Alosetron?

  • Tell all of your health care providers that you take alosetron. This includes your doctors, nurses, pharmacists, and dentists.
  • If you are 65 or older, use alosetron with care. You could have more side effects.
  • Tell your doctor if you are pregnant, plan on getting pregnant, or are breast-feeding. You will need to talk about the benefits and risks to you and the baby.

How is this medicine (Alosetron) best taken?

Use alosetron as ordered by your doctor. Read all information given to you. Follow all instructions closely.

  • Take with or without food.
  • Take alosetron at the same time of day.

What do I do if I miss a dose?

  • Skip the missed dose and go back to your normal time.
  • Do not take 2 doses at the same time or extra doses.

What are some side effects that I need to call my doctor about right away?

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

  • Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.

What are some other side effects of Alosetron?

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at

If OVERDOSE is suspected:

If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

How do I store and/or throw out Alosetron?

  • Store at room temperature.
  • Protect from light.
  • Store in a dry place. Do not store in a bathroom.
  • Keep all drugs in a safe place. Keep all drugs out of the reach of children and pets.
  • Throw away unused or expired drugs. Do not flush down a toilet or pour down a drain unless you are told to do so. Check with your pharmacist if you have questions about the best way to throw out drugs. There may be drug take-back programs in your area.

Consumer information use

  • If your symptoms or health problems do not get better or if they become worse, call your doctor.
  • Do not share your drugs with others and do not take anyone else's drugs.
  • This medicine comes with an extra patient fact sheet called a Medication Guide. Read it with care. Read it again each time alosetron is refilled. If you have any questions about alosetron, please talk with the doctor, pharmacist, or other health care provider.
  • If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.