Anticholinergic Bronchodilators – Study Notes

1. Autonomic Nervous System Overview

• Sympathetic Nervous System (SNS) = “Fight & Flight”

  • Shunts blood to heart, lungs, brain, skeletal muscle

  • Neurotransmitter: Epinephrine, Norepinephrine

  • Drugs that mimic SNS = Sympathomimetics

• Parasympathetic Nervous System (PNS) = “Rest & Digest”

  • Shunts blood to GI tract, kidneys, bladder

  • Controls saliva, urination, digestion

  • Neurotransmitter: Acetylcholine (ACh)

  • Drugs that mimic PNS = Cholinergics

• Think of it like a teeter-totter:

  • Turn off one → the other dominates.

2. Cholinergic vs Anticholinergic

• Cholinergic (PNS ON):

  • “You can See, Spit, Pee, Poop”

  • Moist eyes, saliva, urination, bowel movement

• Anticholinergic (PNS OFF):

  • “You Can’t See, Can’t Spit, Can’t Pee, Can’t Poop”

  • Dry eyes, dry mouth, urinary retention, constipation

  • Blood/energy directed to heart + lungs instead of GI/urinary system

3. Anticholinergics as Bronchodilators

• Block muscarinic ACh receptors in the airway → prevent bronchoconstriction.

• Result: airway relaxation & dilation (more airflow).

Examples

• Atropine (classic anticholinergic, increases HR too)

• Ipratropium (Atrovent)

• Tiotropium (Spiriva)

• Aclidinium, Glycopyrrolate, Umeclidinium (newer long-acting agents)

4. Clinical Uses

• COPD: first-line maintenance therapy (esp. long-acting agents like tiotropium).

• Asthma: sometimes as add-on therapy.

• Emergency use: ipratropium + albuterol (Duoneb) for acute exacerbations.

5. Key Side Effects of Anticholinergics

• Dry mouth (most common)

• Blurred vision (↑ intraocular pressure; avoid in glaucoma)

• Urinary retention (caution in BPH)

• Constipation

• Tachycardia (esp. systemic atropine)

Quick Mnemonic

• Cholinergic = “Rest & Digest” → See, Spit, Pee, Poop

• Anticholinergic = “Fight & Flight” → Can’t See, Can’t Spit, Can’t Pee, Can’t Poop