Cholinergics Flashcards by Jennifer Baker

What is acetylcholinesterase?

An enzyme that breaks down acetylcholine

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What is miosis?

Very constricted pupils

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What is a cholinergic agonist?

Drugs that mimic the effects of the neurotransmitter acetylcholine (and therefore the parasympathetic nervous system)
agonist = to stimulate/increase the effects

Not limited to a specific site –> many undesired systemic effects

Work either directly or indirectly on ACh receptors

(AKA parasympathomimetic)

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What is Myasthenia gravis?

A chronic autoimmune disorder affecting the muscles
Patients make antibodies to ACh receptors, causes destruction of them
Progressive weakness and lack of muscle control with periodic acute episodes

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What is Alzheimer’s Disease?

A progressive disease that causes neural degeneration in the cortex
Leads to marked loss of memory, decreased ability to perform ADLs
Believe there is a progressive loss of ACh producing neurons

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What are the effects of the parasympathetic nervous system?

REST AND DIGEST
* Pupil constriction
* ⬆️ salivation
* ⬆️ respiratory secretions
* ⬆️ peristalsis
* Vasodilation (in most blood vessels)
* Bronchoconstriction
* ⬇️ heart rate
* ⬇️ blood pressure
* Bile release
* Urination

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Lifespan Considerations of Cholinergic Drugs
In Children

Increased risk of adverse effects
Dosages should be based off weight

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Lifespan Considerations of Cholinergic Drugs
In Adults

Caution against driving while on medication
No studies on safety during pregnancy/lactation
Use alternative method to breastfeeding

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Lifespan Considerations of Cholinergic Drugs
In Older Adults

More likely to have adverse effects
More likely to have toxic levels
Start low and go slow
Institute safety precautions

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Direct Acting Cholinergic Agonists
Mechanism of Action

Mimics acetylcholine at the receptor sites (muscarinic or nicotinic) on the surfaces of the target cells of the postganglionic cholinergic nerves
Causes an increased stimulation of the cholinergic receptor

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Direct-Acting Cholinergic Agonists: 🍄Muscarinic
Indications

Urinary Retention (Bethanechol)
To induce miosis (carbachol)
Treat dry mouth (cevimeline & pilocarpine)

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Direct-Acting Cholinergic Agonists: 🍄Muscarinic
Drug Names

Bethanechol (urinary retention)
Carbachol (to induce miosis)
Cevimeline (treats dry mouth)
Pilocarpine (treats dry mouth)

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Direct-Acting Cholinergic Agonists: 🍄Muscarinic
Contraindications

Absolute:
* Allergy
* Any condition that would be exacerbated by parasympathetic effects: Bradycardia, hypotension
* Peptic Ulcer Disease, GI obstruction or recent GI surgery
* Asthma (can cause bronchoconstriction)
* Bladder obstruction
* Epilepsy and parkinsonism (can worsen)

Caution:
* Pregancy and lactation

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Direct-Acting Cholinergic Agonists: 🍄 Muscarinic
Adverse Effects

💩 Diarrhea, involuntary defecation, cramps
🤮 Nausea, vomiting, increased salivation
💓 Bradycardia, heart block, hypotension
🫣 Urinary urgency
💦😳 Flushing or increased sweating

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Direct-Acting Cholinergic Agonists: 🍄Muscarinic
Drug Interactions

Acetylcholinesterase Inhibitors

(Indirect-Acting Cholinergic Agonists)

Can lead to a cholinergic crisis!

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Direct-Acting Cholinergic Agonists: 🍄Muscarinic
Assessment

History:
* Contraindications & Cautions

Physical:
* Vitals
* Lung sounds
* Bowel sounds
* Bladder distention
* Input & Output

Direct-Acting Cholinergic Agonists: 🍄Muscarinic
Nursing Diagnoses

Impaired Comfort (r/t GI effects)
Altered cardiac output (r/t CV effects)
Impaired urinary elimination (r/t GU effects)
Injury risk (r/t blurry vision, changes in visual acuity)
Diarrhea (r/t GI effects)
Knowledge Deficit

Direct-Acting Cholinergic Agonists: 🍄Muscarinic
Implementation/Patient Teaching

Ensure proper administration of opthalmic preparations
Administer oral drugs on an empty stomach
Monitor response closely
Provide safety precautions (fall risk) if pt experiences poor visual acuity
Monitor urinary output

Direct-Acting Cholinergic Agonists: 🚬 Nicotinic
Indications

Smoking cessation

(Work mostly in CNS - quicker acting than muscarinc receptor agonists)

Direct-Acting Cholinergic Agonists: 🚬 Nicotinic
Drug Names

Bupropion (weakly inhibits neuronal reuptake of NE and Dopamine)
Varenicline (acts as nicotine receptor partial agonist)
Nicotine (replacement therapy)

Direct-Acting Cholinergic Agonists: 🚬 Nicotinic
Contraindications

Absolute:
* Allergy
* Seizure disorder (Bupropion) reduces seizure threshold

Caution:
* Pregnancy and lactation

Direct-Acting Cholinergic Agonists: 🚬 Nicotinic
Adverse Effects

💓 Tachycardia, hypertension (due to too much increased fluid)
🧠 Seizures, neuropyschiatric adv. effects, dizziness, strange dreams
🤢Nausea and dry mouth
😡Skin rash (r/t cholinergic urticaria)

MORE potential for CNS effects than muscarinic agonists

Direct-Acting Cholinergic Agonists: 🚬 Nicotinic
Drug Interactions

TOO MANY to name

Direct-Acting Cholinergic Agonists: 🚬 Nicotinic
Assessment

History:
* Contraindications & Cautions
* Amount of tobacco use
* Sleep patterns
* suicidal thoughts and behaviors

Physical:
* Lung sounds
* Heart Sounds
* Vital Signs
* ECG
* mood, affect

**Direct-Acting Cholinergic Agonists: 🚬 Nicotinic** Nursing Diagnoses

* Impaired comfort *(r/t GI effects)* * Altered cardiac output *(r/t CV effects)* * Injury risk *(r/t seizures or neurpsychiatric side effects)* * Knowledge deficit

**Direct-Acting Cholinergic Agonists: 🚬 Nicotinic** Implementation/Patient Teaching

* ensure proper administration of nicotine replacement preparations * Check for med interactions * May be taken with or without food * Dose may be adjusted * Safety precautions for neuropsychiatric effects or seizure activity * Correct # of patches changed at the right times * Take OFF old patches before applying new one * Report changes in CNS effects

**Indirect-Acting Cholinergic Agonists** Indications

* Myasthenia gravis * Alzheimer's Disease

**Indirect-Acting Cholinergic Agonists** Drugs to treat Myasthenia gravis

* **Neostigmine** *(strong influence at neuromuscular junction)* * **Pyridostigmine** *(longer duration of action than neostigmine)* * **Edrophonium** *(diagnostic agent.... no longer used - too many false positives)*

**Indirect-Acting Cholinergic Agonists** Adverse Effects

💓 **Brady**cardia, **hypo**tension 💩 Increased GI activity and secretions 💛 Increased bladder tone = overactive bladder 🟢 Relaxation of GI and Genitourinary sphincters 🫁 Broncho**constriction** 👁️ Pupil **constriction**

**Indirect-Acting Cholinergic Agonists** Drug Interactions

* NSAIDs *(cause GI erosions)* * Cholinergic Drugs *(can cause Increased secretions)* Combining the drugs can lead to a Gastric Bleed

**Indirect-Acting Cholinergic Agonists** Drugs used to treat Alzheimer's Disease

* **Galantamine** *(avail. in solution for easy swallowing)* * **Rivastigmine** *(avail. in solution for easy swallowing)* * **Donepezil** *(once a day dosing, rapidly dissolving tablet)*

How does nerve gas affect Cholinergic receptors?

* **Permanently** and irreversibly binds to **Acetylcholinesterase** --> leads to significant increase in Acetylcholine * Treatment: **Atropine and Pralidoxime *(anticholinergics)***

**Indirect-Acting Cholinergic Agonists** Assessment

**History:** * Contraindications & cautions **Physical:** * Neuro: Orientation, affect, reflexes, ability to perform ADLs * Vital Signs * ECG * Urinary output **Labs:** * Renal and Liver function tests

**Indirect-Acting Cholinergic Agonists** Nursing Diagnoses

* Altered thought processes *(r/t CNS effects)* * Impaired comfort *(r/t GI effects)* * Decreased cardiac output *(r/t blood pressure changes, arrhythmias, and vasodilation)* * Injury risk *(r/t CNS effects)* * Diarrhea *(r/t GI stimulatory effects)* * Knowledge deficit

**Indirect-Acting Cholinergic Agonists** Implementation

* If given via IV, go slowly * Maintain atropine sulfate on standby for cholinergic crisis * Discontinue drug if: excessive salivation, diarrhea, emesis, or frequent urination * Oral drug with meals * If going into surgery, notify surgeon that they are on cholinergic drugs * Monitor Alzheimer's pts for progress * Arrange for supportive care and comfort measures