• See Also
  1. Dicyclomine
  2. Atropine
  3. Anticholinergic Medication
  4. Anticholinergic Toxicity
  5. Parasympathetic Nervous System
  • Indications
  1. Bladder Spasm
  2. Irritable Bowel Syndrome
  3. Decrease gastrointestinal hypermotility
  4. Decrease gastric secretions
  • Contraindications
  1. Narrow Angle Glaucoma
  2. Obstructive Uropathy
  3. Paralytic Ileus
  4. Small Bowel Obstruction
  5. Toxic Megacolon
  6. Myasthenia Gravis
  7. Acute Gastrointestinal Hemorrhage
  • Mechanism
  1. Hyoscyamine is an L-isomer of the belladonna alkaloid, Atropine
  2. Similar to Atropine, Hyoscyamine is an Anticholinergic Agent
    1. Non-selective, competitive Muscarinic Antagonist
  3. Inhibits at various sites
    1. Inhibits Bladder smooth Muscle Contraction
    2. Slows gastrointestinal motility and digestive enzyme secretion
    3. Decreases secretion of Saliva, sweat and Bronchial mucus
  • Medications
  1. Hyoscyamine 0.125 ODT (Anaspaz)
  2. Hyoscyamine 0.125 tablets (Levsin)
  3. Hyoscyamine 0.125 SL (Levsin-SL)
  4. Hyoscyamine 0.125 chewable
  5. Hyoscyamine 0.125/5ml elixir
  6. Hyoscyamine 0.125/ml drops
  7. Hyoscyamine 0.375 Extended Release (Levbid)
  • Dosing
  • Adult (or age >12 years)
  1. Regular release
    1. Take 125 to 250 mcg (0.125 to 0.25 mg) orally (or sublingual) every 4 hours as needed
  2. Extended release (ER)
    1. Take 375 to 750 mcg (0.375 to 0.75 mg) orally every 12 hours
  3. Maximum
    1. Limit to 1500 mcg (1.5 mg) per day
  • Dosing
  • Child
  1. Note that dosing is in mcg (not mg)
  2. Age <2 years: Dose up to every 4 hours as needed (maximum of 6 doses daily)
    1. Weight 2.3 kg: Give 12.5 mcg (or 3 drops of 0.125 mg/ml)
    2. Weight 3.4 kg: Give 16.7 mcg (or 4 drops of 0.125 mg/ml)
    3. Weight 5 kg: Give 20.8 mcg (or 5 drops of 0.125 mg/ml)
    4. Weight 7 kg: Give 25 mcg (or 6 drops of 0.125 mg/ml)
    5. Weight 10 kg: Give 32 mcg (or 8 drops of 0.125 mg/ml)
    6. Weight 15 kg: Give 46 mcg (or 11 drops of 0.125 mg/ml)
  3. Age 2 to 12 years: Dose up to every 4 hours as needed (maximum 750 mcg/day)
    1. Weight 20 kg: Give 62.5 mcg orally every 4 hours as needed
    2. Weight 40 kg: Give 93.8 mcg orally every 4 hours as needed
    3. Weight 50 kg: Give 125 mcg orally every 4 hours as needed
  4. Age >12 years
    1. Use adult dosing
  • Adverse Effects
  1. See Anticholinergic Toxicity
  2. Somnolence
  3. Dizziness
  4. Xerostomia
  5. Urinary Retention
  6. Blurred Vision
  • Safety
  1. Pregnancy Category C
  2. Unknown safety in Lactation
  • Resources
  1. Hyoscyamine (DailyMed)
    1. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=49fe1783-ab0c-4adb-869b-384121cf7f05
  • References
  1. (2020) Med Lett Drugs Ther 62(1594): 41-58
  2. Hamilton (2020) Tarascon Pocket Pharmacopoeia