Lotronex (generic: alosetron) is a prescription medication used to treat women with the symptoms of severe irritable bowel syndrome (IBS) including diarrhea, pain, cramps, and the urgent need to have bowel movements. Lotronex belongs to a group of drugs called serotonin agonists which work by slowing the movement of stool through the intestines.

This medication comes in tablet form and is usually taken twice daily, with or without food.

Common side effects of Lotronex include constipation and nausea.