III. Contraindications

  1. History of Ischemic Colitis (including from Alosetron)
  2. Fluvoxamine concurrent use (CYP1A2 Inhibitor)
  3. Constipation
  4. Crohns Disease
  5. Intestinal Obstruction
  6. Severe liver disease

IV. Precautions

  1. FDA Black box warning
    1. Deaths have occurred due to Ischemic Colitis
    2. Requires signed Informed Consent before prescribing

V. Mechanism

  1. Potent, selective 5-HT3 Receptor Antagonist
  2. Blocks Serotonin at 5-HT3 receptors throughout Peripheral Nervous System including the Gastrointestinal System
  3. Effects (similar to Ondansetron)
    1. Decreases gastrointestinal motility (decreases rapid transit and stool urgency)
    2. Decreases gastrointestinal secretions

VI. Dosing

  1. Start 0.5 mg orally twice daily for 4 weeks
  2. Next: Increase to 1 mg orally twice daily if tolerated

VII. Adverse Effects

  1. Common
    1. Abdominal Pain
    2. Nausea
    3. Constipation
  2. Serious
    1. Ischemic Colitis (deaths have occurred)

VIII. Safety

  1. Pregnancy Category B
  2. Unknown safety in Lactation

XI. References

  1. (2021) Irritable Bowel Syndrome Drug Comparison, Presc Lett, #370305
  2. (2020) Med Lett Drugs Ther 62(1594): 41-58

Images: Related links to external sites (from Bing)

Related Studies

Cost: Medications

alosetron (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing)
ALOSETRON HCL 0.5 MG TABLET Generic $4.67 each
ALOSETRON HCL 1 MG TABLET Generic $6.20 each