Pharm

Alosetron

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Alosetron, Lotronex

  • See Also
  1. Irritable Bowel Syndrome
  • Indications
  1. Diarrhea Dominant Irritable Bowel Syndrome in women
  • 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
  • Precautions
  1. FDA Black box warning
    1. Deaths have occurred due to Ischemic Colitis
    2. Requires signed Informed Consent before prescribing
  • 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
  • Dosing
  1. Start 0.5 mg orally twice daily for 4 weeks
  2. Next: Increase to 1 mg orally twice daily if tolerated
  • Adverse Effects
  1. Common
    1. Abdominal Pain
    2. Nausea
    3. Constipation
  2. Serious
    1. Ischemic Colitis (deaths have occurred)
  • Safety
  1. Pregnancy Category B
  2. Unknown safety in Lactation
  • Drug Interactions
  1. CYP1A2 Inhibitors
    1. Fluvoxamine (contraindicated)
    2. Fluoroquinolone
    3. Cimetidine
  2. CYP3A4 Inhibitors
    1. Ketoconazole, Voriconazole, Itraconazole
    2. Clarithromycin
    3. Protease Inhibitors
  • Resources
  1. Alosetron (DailyMed)
    1. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=526ba44c-a476-4675-a63c-4d0a72b723f5
  • References
  1. (2021) Irritable Bowel Syndrome Drug Comparison, Presc Lett, #370305
  2. (2020) Med Lett Drugs Ther 62(1594): 41-58