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Lotronex

Generic name: alosetron (oral) [ a-LO-ze-tron ]
Drug class: Serotoninergic neuroenteric modulators

Medically reviewed by Philip Thornton, DipPharm. Last updated on Aug 23, 2023.

What is Lotronex?

Lotronex 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 with 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.

Warnings

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

Do not start taking Lotronex 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 Lotronex. In rare cases, Lotronex has caused severe constipation, or ischemic colitis (caused by reduced blood flow to the intestines).

Stop taking this medicine 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 this medicine if you have these side effects.

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

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

Before taking this medicine

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

Tell your doctor if you are pregnant or breastfeeding.

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

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

How should I take Lotronex?

Take Lotronex exactly as prescribed by your doctor. Follow all directions on your prescription label. Your doctor may occasionally change your dose to make sure you get the best results. Do not use this medicine in larger or smaller amounts or for longer than recommended.

Read all patient information, medication guides, and instruction sheets provided to you. Ask your doctor or pharmacist if you have any questions.

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

You may take this medicine with or without food.

Lotronex does not improve the symptoms of IBS for everyone. This medicine 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 Lotronex and call your doctor if your IBS symptoms do not improve after 4 weeks of treatment.

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

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

Dosing 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.

Comments:
-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.

What other drugs will affect Lotronex?

Many drugs can interact with alosetron, and some drugs should not be used together. This includes prescription and over-the-counter medicines, vitamins, and herbal products.

Some drugs can affect your blood levels of other drugs you take, which may increase side effects or make the medications less effective. Tell your doctor about all medicines you use, and those you start or stop using during your treatment with Lotronex. Give a list of all your medicines to any healthcare provider who treats you.

What happens if I miss a dose?

Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

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

What to avoid

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

Lotronex 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:

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:

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.

What other drugs will affect Lotronex?

Many drugs can interact with alosetron, and some drugs such as fluvoxamine, quinolone antibiotics, cimetidine, ketoconazole, clarithromycin, telithromycin, protease inhibitors, voriconazole, and itraconazole should not be used with alosetron.

Not all possible interactions are listed in this medication guide. Tell your doctor about all medicines you use, and those you start or stop using during your treatment with Lotronex. Give a list of all your medicines to any healthcare provider who treats you.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Lotronex only for the indication prescribed.

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