1. Drugs Affecting the Autonomic Nervous System
Cholinergic Drugs
Drugs Affecting the Autonomic Nervous System

2. Cholinergic Drugs
Describe the cholinergic drug effects on major body systems.
Discuss the nursing process related to the care of patients receiving cholinergic drugs for select problems.

3. Cholinergic Drugs
Drugs that stimulate the parasympathetic nervous system (PSNS)
opposing system to the SNS
Known as: cholinergic agonists or parasympathomimetics
Mimic the effects of the PSNS neurotransmitter: acetylcholine (Ach)
Two types of Receptors:
determined by: Location & Action once stimulated
Muscarinic receptors – recommended doses with desired effect
Nicotinic receptors – higher doses with undesirable effects

5. Cholinergic Drugs Mechanism of Action
Direct-acting cholinergic agonists
Bind to cholinergic receptors, activating them
Indirect-acting cholinergic agonists
Inhibit the enzyme acetylcholinesterase - preventing, which breaks down ACh - more ACh is available at the receptors
Reversible - Bind to cholinesterase for a period of minutes to hours
Irreversible - Bind to cholinesterase and form a permanent covalent bond
The body must make new cholinesterase to break these bonds

6. Cholinergic Drugs “rest and digest” system
“SLUDGE”
Salivation
Lacrimation
Urinary incontinence
Diarrhea
Gastrointestinal cramps
Emesis

7. Cholinergic Drugs Drug Effects
Stimulate intestine and bladder
Increased gastric secretions
Increased gastrointestinal motility
Increased urinary frequency
Stimulate pupils
Constriction (miosis)
Reduced intraocular pressure
Increased salivation and sweating
Cardiovascular effects
Decreased heart rate
Vasodilation
Respiratory effects
Bronchial constriction, narrowed airways

8. Cholinergic Drugs Drugs
Bethanechol (Urecholine) – urinary retention
Cevimeline (Evoxac) – Xerostomia
Memantine (Namenda) – Alzheimer’s dementia
Physostigmine (Antilirium) – reversal of anticholinergic drugs effects
Pyridostigmine (Mestinon) – Myasthenia gravis

9. Cholinergic Drugs Indications
Direct-acting drugs
Reduce intraocular pressure
Topical useful for glaucoma and intraocular surgery
pilocarpine

10. Cholinergic Drugs Indications
Direct-acting drug—bethanechol (Urecholine)
Increases tone and motility of bladder and GI tract
Relaxes sphincters in bladder and GI tract, allowing them to empty
Used to reverse postsurgical atony of the bladder and GI tract
Oral dose or SC injection

11. Cholinergic Drugs Indications
Indirect-acting drugs
Cause skeletal muscle contractions
Used for diagnosis and treatment of myasthenia gravis
Pyridostigmine (Mestinon) – Myasthenia gravis
Used to reverse neuromuscular blocking drugs/anesthesia
Used to reverse anticholinergic poisoning (antidote)
Examples: physostigmine (Antilirium)

12. Cholinergic Drugs Indications
Indirect-acting drugs—cevimeline (Evoxac)
Used to treat xerostomia (dry mouth) resulting from Sjögren’s syndrome

13. Cholinergic Drugs Adverse Effects
Adverse effects are a result of overstimulation of the PSNS
Cardiovascular
Bradycardia, hypotension, conduction abnormalities (AV block and cardiac arrest)
CNS
Headache, dizziness, convulsions
Gastrointestinal
Abdominal cramps, increased secretions, nausea, vomiting
Respiratory
Increased bronchial secretions, bronchospasm
Other
Lacrimation, sweating, salivation, loss of binocular accommodation, miosis

14. Cholinergic Drugs Interactions
Anticholinergics, antihistamines, sympathomimetics
Antagonize cholinergic drugs, resulting in decreased responses
Other cholinergic drugs
Additive effects

15. Cholinergic Drugs Nursing Implications
Assess for allergies, presence of GI or GU obstructions, asthma, peptic ulcer disease, or coronary artery disease
Perform baseline assessment of vital signs and systems overview
Medications should be taken as ordered and not abruptly stopped
The doses should be spread evenly apart to optimize the effects of the medication
Overdosing can cause life-threatening problems. Only physicians should adjust the dosages

16. Cholinergic Drugs Nursing Implications
Encourage patients with myasthenia gravis to take medication 30 minutes before eating to help improve chewing and swallowing
When cholinergic drugs are prescribed for Alzheimer’s disease, be honest with caregivers and patients that the drugs are for management of symptoms, not a cure
Therapeutic effects of anti-Alzheimer’s drugs may not occur for up to 6 weeks

17. Cholinergic Drugs Nursing Implications
Monitor for therapeutic effects
Alleviated signs and symptoms of myasthenia gravis
In postoperative patients with decreased GI peristalsis, look for:
Increased bowel sounds
Passage of flatus
Occurrence of bowel movements
In patients with urinary retention/hypotonic bladder, urination should occur within 60 minutes of bethanechol administration
ALSO monitor for adverse effects