Cholinergic

• Cholinergic agonists


  Drugs that stimulate the parasympathetic nervous system
• Parasympathomimetics


  Drugs that mimic the parasympathetic neurotransmitter acetylcholine
• Acetylcholine (ACh)


  The neurotransmitter located at the ganglions and the parasympathetic terminal nerve endings
• Muscarinic receptors


  • Stimulate smooth muscle and slow the heart rate
• Nicotinic receptors


  • Affect the skeletal muscles
• Types of cholinergic agonists

  • Direct-acting
  • Indirect-acting
• Direct-acting cholinergic agonists


  Act on receptors to activate a tissue response
• Indirect-acting cholinergic agonists


  Inhibit the action of the enzyme cholinesterase (ChE), also called acetylcholinesterase (AChE), allowing acetylcholine to persist and attach to the receptor
• Cholinesterase inhibitors


  Drugs that inhibit ChE
• Bethanechol chloride


  A direct-acting cholinergic agonist that acts on the muscarinic (cholinergic) receptor and is used primarily to increase urination in the treatment of urinary retention and neurogenic bladder
• Metoclopramide hydrochloride


  A direct-acting cholinergic agonist that is usually prescribed to treat gastroparesis, nausea, and gastroesophageal reflux disease (GERD)
• Pilocarpine


  A direct-acting cholinergic agonist that constricts the pupils of the eyes, thus opening the Schlemm canal to promote drainage of aqueous humor (fluid), used to treat glaucoma and promote miosis in eye surgery and examinations
• Reversible cholinesterase inhibitors


  Used to produce pupillary constriction in the treatment of glaucoma and to increase muscle strength in patients with myasthenia gravis, drug effects persist for several hours
• Physostigmine


  A reversible anticholinesterase drug used as an antidote for atropine to reverse anticholinergic toxicity
• Irreversible cholinesterase inhibitors


  Potent agents with long-lasting effects, used to produce pupillary constriction
• Cholinergic antagonists


  Drugs that inhibit the actions of acetylcholine by occupying the acetylcholine receptors, also called muscarinic antagonists, anticholinergics, cholinergic blocking agents, antispasmodics, or parasympatholytics
• Anticholinergics and cholinergic agonists

  Have opposite effects
• Atropine


  A classic anticholinergic or muscarinic antagonist drug
• Scopolamine


  The second belladonna alkaloid produced
• Antiparkinson-Anticholinergic Drugs


  Suppress tremors and muscular rigidity of parkinsonism, but have little effect on mobility and muscle weakness
• Benztropine


  Decreases involuntary movement and diminishes tremors and muscle rigidity of parkinsonism and pseudoparkinsonism