Definition of "Anticholinergic"

Last modified: 13 hours

Anticholinergics inhibits parasympathetics, by blocking the neurotransmitter acetylcholine [specifically, its binding to its receptor in neurons]. Parasympathetics are responsible for involuntary movement of smooth muscle present in the GI, urinary tract, lungs, etc.

Patient information

What are anticholinergics?
It's drugs that inhibit the parasympathetics, which is the rest and digest response, by blocking acetylcholine. So rest and digest includes digestion, urination, and constriction of the breathing tubes.

  • GI disorders, including:
    • Gastritis
    • Diarrhea
    • Pylorospasm
    • Diverticulitis
    • UC
    • Nausea
    • Vomiting
  • Genitourinary disorders, including:
    • Cystitis
    • Urethritis
    • Prostatitis
  • Respiratory disorders, including:
    • Asthma
    • Chronic bronchitis
    • COPD
  • Sinus bradycardia, due to a hypersensitive vagus nerve
  • Insomnia, although usually only on a short term basis
  • Dizziness, including vertigo, and motion sickness-related Sx

Patient information

When do you want to give a drug to inhibit the rest and digest response?
If there's a GI problem, like diarrhea, diverticulitis, ulcerative colitis, vomiting. If there's a urinary problem, like inflammation of the bladder, urethra, or prostate. If there's a breathing problem, like asthma, or COPD.


Anticholinergics can be divided into their specific targets:

  • Antimuscarinics, which block activity of the muscarinic ACh receptor. These include:
    • Aclidinium bromide (Genuair)
    • Atropine
    • Atropine methonitrate
    • Benzatropine
    • Biperiden
    • Chlorpheniramine
    • Cyclopentolate
    • Darifenacin
    • Dicyclomine
    • Dimenhydrinate
    • Diphenhydramine
    • Doxylamine
    • Flavoxate
    • Glycopyrronium bromide (aka Glycopyrrolate, Seebri)
    • Hydroxyzine
    • Ipratropium [bromide] (Atrovent), which relieves bronchspasms. It is used to Tx COPD and acute asthma
    • Mebeverine
    • Orphenadrine
    • Oxitropium
    • Oxybutynin
    • Pirenzepine
    • Procyclidine
    • Scopolamine (Hyoscine)
    • Solifenacin
    • Tolterodine
    • Tiotropium [bromide] (Spiriva), used to Mx COPD
    • Trihexyphenidyl +/- Benzhexol
    • Tropicamide
  • Antinicotincs, including:
    • Bupropion
    • Dextromethorphan
    • Doxacurium
    • Hexamethonium
    • Mecamylamine
    • Tubocurarine
  • [Post-]ganglionic blockers, by acting as a nicotinic antagonist
  • Neuromuscular blockers, which act presynaptically via inhibition of acetylcholine ACh, or postsnaptically at the ACh receptors of the motor nerve end-plate. This causes paralysis of the affected skeletal muscles

Patient information

What are the different types of drugs that inhibit the rest and digest response?
The biggies are the antimuscarinics and antinicotinics. As it's mentioned, it acts against the muscarinic and nicotinic receptors. They're both receptors that bind acetylcholine.

Side effects
  • Decreased mucus production in the nose and throat, causing dry, sore throat
  • Dry mouth w/ possible acceleration of dental caries
  • Pupil dilation, causing photophobia (sensitivity to bright light)
  • Tachycardia (increased HR)
  • Diminished bowel movement, sometimes ileus (decreased motility via the vagus nerve)
  • Urinary retention
  • Ataxia (poor coordination)
  • Dementia
  • Stopping of sweating, causing decreased epidermal thermal dissipation causing warm, blotchy, or red skin
  • Increased body temperature
  • Loss of accommodation, loss of focusing ability, blurred vision
  • Double vision
  • Tendency to be easily startled
  • Increased IOP (intraocular pressure), dangerous for Pt's w/ narrow-angle glaucoma

Patient information

What are the side effects of the drugs that inhibit the rest and digest response?
Because you're inhibiting the rest and digest response, you'd be worried about promoting things associated with the fight and flight response. So things like decreased mucus production, dry mouth, pupil dilation, increased heart rate, slower bowel movement, urinary retention.

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Definition of Anticholinergic | Autoprac

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