alosetron
Alosetron (Lotronex) is a serotonin antagonist. It's used to treat severe irritable bowel syndrome with diarrhea (IBS-D) in adult females. But alosetron (Lotronex) isn't a first-choice option and is typically only prescribed when other treatments haven't worked well. Alosetron (Lotronex) comes as tablets that are taken by mouth, typically twice a day. Some common side effects include constipation, stomach pain, and nausea. It's available under the brand name Lotronex and as a lower-cost generic.
What is Alosetron (Lotronex)?
What is Alosetron (Lotronex) used for?
Severe irritable bowel syndrome with diarrhea (IBS-D) in females (when other treatment options haven't worked well)
How Alosetron (Lotronex) works
Alosetron (Lotronex) is a selective serotonin 5-HT3 antagonist. It works by blocking serotonin (a signaling protein) from binding to its receptors the gut that are involved in pain and secretions. This helps ease stomach discomfort, pain, and diarrhea.
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What are the side effects of Alosetron (Lotronex)?
Common Side Effects
- Constipation (29%)
- Abdominal discomfort and pain (7%)
- Nausea (6%)
Other Side Effects
- Bloating
- Heartburn, acid reflux
- Hemorrhoids
Serious Side Effects
- Ischemic colitis: fever, bloating, worsening stomach pain, rectal bleeding, blood in stool, bloody diarrhea
- Severe constipation
Source: DailyMed
The following side effects have also been reported
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
More common
Get emergency help immediately if any of the following symptoms of overdose occur:
Symptoms of overdose
Clumsiness, unsteadiness, trembling, or other problems with muscle control or coordination
convulsions (seizures)
difficulty breathing
shakiness and unsteady walk
withdrawn or socially detached behavior
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Less common
Bleeding after bowel movement
full or bloated feeling
pressure in the stomach
swelling of abdominal or stomach area
uncomfortable swelling around rectal area
Incidence not known
Headache
skin rash
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Pros and cons of Alosetron (Lotronex)
Pros
Might be a good option if other medications haven't worked for diarrhea
Available as a lower-cost generic
Not a controlled medication, like some other antidiarrheals
Cons
Not currently FDA approved for males
Can't be used in people with serious liver or gut conditions
Must be taken twice a day
Pharmacist tips for Alosetron (Lotronex)
You can take alosetron (Lotronex) with or without food.
Tell your prescriber if you're still having diarrhea after taking alosetron (Lotronex) for a month. They might need to raise your dose or talk with you about other options.
Stop taking alosetron (Lotronex) and contact your prescriber if you start having constipation, bloody diarrhea, or blood in your stool. This could be a sign of a more serious problem with your gut.
If you've had constipation while taking alosetron (Lotronex), your prescriber might lower your dose or ask you to stop taking it. Don't restart alosetron (Lotronex) unless your prescriber says it's safe to do so. Typically, they'll ask you to wait until you're no longer constipated.
Make sure your care team has a full list of the medications you're taking so they can check for interactions with alosetron (Lotronex). You can't take alosetron (Lotronex) with certain medications, such as fluvoxamine, because doing so can raise the level of alosetron (Lotronex) in your body and put you at higher risk for constipation and other serious gut problems.
Frequently asked questions about Alosetron (Lotronex)
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What are the risks and warnings for Alosetron (Lotronex)?
Alosetron (Lotronex) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Serious gut problems
Risk factors: Taking other medications that can cause constipation
Constipation is one of the more common side effects of alosetron (Lotronex). If left untreated, constipation can lead to serious complications, including gut block. To lower the risk of constipation, your prescriber will have you take the lowest dose of alosetron (Lotronex) needed to treat your condition. If you experience constipation with alosetron (Lotronex), your prescriber will ask you to stop treatment. Depending on your condition, your prescriber might ask you to restart alosetron (Lotronex) once the constipation gets better, or ask you to consider other treatment options.
Though rare, some people who took alosetron (Lotronex) have also reported ischemic colitis, a potentially life-threatening condition where there isn't enough blood flow to the intestines. Symptoms of ischemic colitis include bloating, bloody stools or diarrhea, and worsening stomach pain. Stop taking alosetron (Lotronex) and get medical help right away if you develop symptoms of ischemic colitis. You won't be able to take alosetron (Lotronex) if you experience ischemic colitis.
Alosetron (Lotronex) dosage forms
Typical dosing for Alosetron (Lotronex)
Adults: The typical starting dose is 0.5 mg by mouth two times a day. After a month of treatment, your prescriber might raise your dose to 1 mg two times a day, if needed.
Interactions between Alosetron (Lotronex) and other drugs
Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
- Apomorphine
- Fluvoxamine
- Viloxazine
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Capmatinib
- Cimetidine
- Ciprofloxacin
- Gatifloxacin
- Givosiran
- Norfloxacin
- Ofloxacin
Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
How much does Alosetron (Lotronex) cost?
Alosetron (Lotronex) contraindications
Currently constipated
History of severe or long-term constipation
Certain gut problems, including blockage in the intestines, narrowing of intestines, toxic megacolon, or tear in the gut
Reduced blood flow to the intestines (ischemic colitis)
Bleeding disorders
Serious liver problems
What are alternatives to Alosetron (Lotronex)?
Severe irritable bowel syndrome with diarrhea (IBS-D) in females (when other treatment options haven't worked well)
What is the latest news about Alosetron (Lotronex)?
Alosetron (Lotronex) images
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References
Best studies we foundAmneal Pharmaceuticals of New York LLC. (2023). Alosetron hydrochloride tablet, film coated [package insert]. DailyMed.
Butt, I., et al. (2024). Alosetron. StatPearls.
Camilleri, M., et al. (2001). A randomized controlled clinical trial of the serotonin type 3 receptor antagonist alosetron in women with diarrhea-predominant irritable bowel syndrome. Archives of Internal Medicine.
Chang, L., et al. (2005). A dose-ranging, phase II study of the efficacy and safety of alosetron in men with diarrhea-predominant IBS. The American Journal of Gastroenterology.
Desai, J., et al. (2020). Toxic megacolon: Background, pathophysiology, management challenges and solutions. Clinical and Experimental Gastroenterology.
Koch, K., et al. (2004). Pharmacodynamics and pharmacokinetics of oral contraceptives co-administered with alosetron (Lotronex). Digestive Diseases and Sciences.
Lembo, A., et al. (2022). AGA Clinical Practice Guideline on the pharmacological management of irritable bowel syndrome with diarrhea. Gastroenterology.
van Kessel, L., et al. (2021). Sex-gender differences in the effectiveness of treatment of irritable bowel syndrome: A systematic review. International Journal of General Medicine.
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