Alosetron
Alosetron is a medication prescribed for women with irritable bowel syndrome with diarrhea (IBS-D), working by blocking 5-HT3 receptors to reduce bowel symptoms.
Alosetron is a 5-HT3 receptor antagonist used to treat diarrhea-predominant IBS in women under a restricted prescribing program.
This medication carries a boxed (black box) warning — the strongest type of FDA warning. Review the full prescribing information before use.
Key facts at a glance
- ATC
- A03AE01
- RxNorm
- 85248
- Generic
- Alosetron
- Class
- atc-a03
- Brands
- Lotronex
- Availability
- rx
- Lactation
- unknown
- Routes
- oral
- Forms
- tablet
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Dosage and administration
- Usual dose
- 0.5mg twice daily
- Maximum
- consult physician
- Frequency
- every 12 hours
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 0.5mg once daily
- Maximum
- consult physician
- Frequency
- once daily
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 0.5mg once daily
- Maximum
- consult physician
- Frequency
- once daily
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
Overdose information
Special Populations
8 groupspregnancy
first trimesteravoid unless benefits outweigh risks
use only if clearly needed, avoid in first trimester unless benefits outweigh potential risks
regular prenatal monitoring
Use with caution and monitor for adverse effects.
pregnancy
second trimesteruse lowest effective dose
use only if benefits outweigh risks
regular prenatal monitoring
Use with caution and monitor for adverse effects.
pregnancy
third trimesteruse lowest effective dose
discontinue before delivery if possible
fetal monitoring near term
Use with caution and monitor for adverse effects.
lactation
breastfeedingavoid or discontinue breastfeeding
not recommended during breastfeeding due to unknown excretion in breast milk
monitor infant for adverse effects
pediatric_age
age less than 18not recommended
not approved for use in pediatric patients under 18 years of age
not applicable
Use of this medication in this population requires careful consideration of risks and benefits.
geriatric
elderly 65start with lower dose
use with caution, increased sensitivity to adverse effects, start at 0.5mg
monitor for constipation and ischemic colitis
Use with caution and monitor for adverse effects.
renal_impairment
severe renaluse with caution, consider dose reduction
use cautiously in severe renal impairment, not recommended in end-stage renal disease
monitor renal function and for adverse effects
Use with caution and monitor for adverse effects.
hepatic_impairment
moderate hepaticdose reduction recommended
reduce dose in moderate hepatic impairment, avoid in severe hepatic impairment
monitor liver function tests
Use with caution and monitor for adverse effects.
Statistics and clinical data
FDA approval year
Alosetron was initially approved by the FDA in February 2000
Drug class
Pharmacological classification based on mechanism of action
Primary indication
Therapeutic indication for Alosetron (Lotronex)
Market status
Drug was withdrawn in November 2000 due to safety concerns and reintroduced in 2002 with restricted access program
Alosetron is indicated for the treatment of irritable bowel syndrome with diarrhea (IBS-D) in women who have not responded adequately to conventional therapies.
Alosetron is a potent and selective 5-HT3 receptor antagonist. 5-HT3 receptors are ligand-gated cation channels extensively distributed on enteric neurons in the GI tract. By blocking these receptors, alosetron reduces intestinal secretion, slows GI motility, and decreases visceral sensitivity.
Due to risks of serious GI adverse events including ischemic colitis and severe constipation with complications, alosetron is only available through a restricted prescribing program (Risk Evaluation and Mitigation Strategy). It is contraindicated in men, patients with constipation-predominant IBS, and those with a history of bowel obstruction. Patients should seek immediate medical attention if they experience severe constipation, rectal bleeding, or new or worsening abdominal pain.
Contraindications
Conditions and patient states where this medication should be avoided or used with caution.
Do not use (1)
Known allergy to this medication or its components
Use caution (1)
Consult healthcare provider for benefits vs risks assessment
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed July 26, 2026. · Read our editorial policy