Lotronex: Uses & Side Effects

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

Lotronex is used to treat severe, chronic irritable bowel syndrome (IBS) in women who have had diarrhea as the main symptom for at least 6 months. Alosetron should be used only by women who have tried other IBS treatments without success. Alosetron not been shown to be effective in men with IBS.

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

Before taking this medicine

Do not take Lotronex 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).

Lotronex is not expected to harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment.

It is not known whether alosetron passes into breast milk or if it could harm a nursing baby. Tell your doctor if you are breast-feeding a baby.

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

Side effects

Get emergency medical help if you have signs of an allergic reaction to Lotronex: 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 Lotronex. In rare cases, alosetron has caused severe constipation, or ischemic colitis (caused by reduced blood flow to the intestines).

Stop taking Lotronex 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 Lotronex 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 Lotronex side effects may include:

  • constipation;
  • nausea; or
  • pain or discomfort in your stomach or intestines.


Keywords: Lotronex; alosetron.

* The Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.