Medicine & USMLE


  1. Atropine (Homatropine and Tropicamide)
  2. Glycopyrrolate
  3. Hyoscyamine & Dicyclomine
  4. Oxybutynin Solifenacin Tolterodine
  5. Scopolamine


Glycopyrrolate is an anticholinergic drug, specifically a muscarinic antagonist that mostly inhibits the parasympathetic rest and digest response, which is generally mediated by muscarinic receptors. Clinically, glycopyrrolate is used to reduce airway saliva and secretions for patients undergoing anesthesia or those with chronic drooling due to a neurologic condition.

Key Points

  • Glycopyrrolate
    • Mechanism
      • Muscarinic antagonist
    • Clinical Use
      • Reduces secretions
        • drooling (e.g. cerebral palsy) 
        • airway secretions (e.g. preoperative anesthesia)
        • Also paired with neostigmine for reversal of paralysis in anesthesia
          • Neostigmine increases ACh at nicotinic (NMJ) but also systemic muscarinic effects, which are blocked by glycopyrrolate
      • Peptic ulcers (PUD)
        • Reduction in cholinergic signaling to parietal cells reduces acid production
        • Less effective than H2 histamine blockers (e.g. cimetidine) or PPIs (e.g. omeprazole)