cholinergic drugs. describe the cholinergic drug effects on major body systems. discuss the...
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Cholinergic Drugs
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.
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
Cholinergic DrugsMechanism 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
Cholinergic Drugs“rest and digest” system
“SLUDGE”
Salivation Lacrimation Urinary incontinence Diarrhea Gastrointestinal cramps Emesis
Cholinergic DrugsDrug 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
Cholinergic DrugsDrugs
Bethanechol (Urecholine) – urinary retention
Cevimeline (Evoxac) – Xerostomia Memantine (Namenda) – Alzheimer’s
dementia Physostigmine (Antilirium) – reversal
of anticholinergic drugs effects Pyridostigmine (Mestinon) –
Myasthenia gravis
Cholinergic DrugsIndications
Direct-acting drugs Reduce intraocular pressure
Topical useful for glaucoma and intraocular surgery pilocarpine
Cholinergic DrugsIndications
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
Cholinergic DrugsIndications
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)
Cholinergic DrugsIndications
Indirect-acting drugs—cevimeline (Evoxac)
Used to treat xerostomia (dry mouth) resulting from Sjögren’s syndrome
Cholinergic DrugsAdverse 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
Cholinergic DrugsInteractions
Anticholinergics, antihistamines, sympathomimetics Antagonize cholinergic drugs, resulting
in decreased responses Other cholinergic drugs
Additive effects
Cholinergic DrugsNursing 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
Cholinergic DrugsNursing 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
Cholinergic DrugsNursing 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