Cholinergic Blocking Flashcards by tyler brenda

Cholinergic-Blocking Drugs

Drugs that block or inhibit the actions of acetylcholine (ACh) in the parasympathetic nervous system (PSNS)
Also known as anticholinergics, parasympatholytics, and antimuscarinic drugs

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Mechanism of action of cholinergic-blocking drugs

Competitive antagonists
Compete with ACh for binding at muscarinic receptors in the PSNS
- As a result, ACh is unable to bind to thereceptor site and cause a cholinergic effect.
When these drugs bind to receptors, they inhibit nerve transmission at these receptors.

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Cholinergic-Blocking Drugs: Natural Plant Alkaloids

Atropine sulphate
scopolamine hydropbromide

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Cholinergic-Blocking Drugs: Synthetic and semisynthetic

glycopyrrolate
oxybutynin (Ditropan®)
tolterodine (Detrol®)

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Drug Effects; Cardiovascular

Small doses: decreased heart rate
doses: increased heart rate

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Drug Effects; Central nervous system (CNS)

Small doses: decreased muscle rigidity and tremors
Large dose: drowsiness, disorientation, hallucinations

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Drug effects; EYE

Dilated pupils (mydriasis)
Decreased accommodation caused by paralysis of ciliary muscles (cycloplegia)

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Drug effects; Gastrointestinal (GI)

Relaxed smooth muscle tone of GI tract
Decreased intestinal and gastric secretions
Decreased motility and peristalsis

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Drug Effects; Genitourinary (GU)

Relaxed detrusor muscle
Increased constriction of internal sphincter
Result: urinary retention

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Drug Effects; Glandular

Decreased sweating

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drug effects; Respiratory

Decreased bronchial secretions

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Indications: Central Nervous System

Decreasing muscle rigidity and muscle tremors
Parkinson’s disease (becoming less trendy)
Drug-induced extrapyramidal reactions such as those associated with antipsychotic drugs

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Indications: Cardiovascular

Affects the heart’s conduction system.
- Low doses: slow the heart rate
- High doses:, block inhibitory vagal effects on sinoatrial and atrioventricular node pacemaker cells
- Results in increased heart rate

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Indications: Cardiovascular - atropine

Used primarily for cardiovascular disorders
Diagnosis of sinus node dysfunction
Symptomatic second-degree heart block
Severe sinus bradycardia with hemodynamic compromise (advanced life support)

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Indications: Respiratory

Blocking the cholinergic stimulation of the PSNS allows unopposed action of the sympathetic nervous system.

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Indications: Respiratory, Results

Decreased secretions from the nose, mouth, pharynx, and bronchi
Relaxed smooth muscles in the bronchi and bronchioles
Decreased airway resistance
Bronchodilation

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Indications: Respiratory, Cholinergic blockers are used to treat:

Exercise-induced bronchospasms
Asthma
Chronic obstructive pulmonary disease

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Indications: Gastrointestinal

The PSNS controls gastric secretions and smooth muscles that produce gastric motility.

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Indications: Gastrointestinal, Blockade of PSNS results in:

Decreased secretions
Relaxation of smooth muscle
Decreased GI motility and peristalsis

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Indications: Gastrointestinal, GI drugs are used to treat what?

Irritable bowel disease
GI hypersecretory states

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Indications: Genitourinary

Reflex neurogenic bladder
Incontinence

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Contraindications

Known drug allergy
Angle-closure glaucoma
Acute asthma or other respiratory distress
Myasthenia gravis
Acute cardiovascular instability
GI or GU tract obstruction (e.g., benign prostatic hyperplasia [BPH]) or illness

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Adverse Effects, Body system/adverse effects, Cardiovascular:

Increased heart rate, dysrhythmias

Body system/adverse effects, CNS:

CNS excitation, restlessness, irritability, disorientation, hallucinations, delirium

Body system/ adverse effects; eyes

Dilated pupils (causing blurred vision), increased intraocular pressure

body system/adverse effects, GI

Decreased salivation, decreased gastric secretions, decreased motility (causing constipation)

body system/adverse effects: GU

urinary retention

body systems/adverse effect, glandular

decreased sweating

body systems/ adverse effects, respiratory

Decreased bronchial secretions

Toxicity and Overdose

Symptomatic and supportive therapy Continuous electrocardiographic monitoring Activated charcoal Treatment of shock Physostigmine (this is a cholinergic drug)

what are the interactions?

Amantadine, antihistamines, phenothiazines, digoxin

whats the result when given together with the interaction drugs?

When the above drugs are given with other cholinergic-blocking drugs, cause additive cholinergic effects, resulting in increased effects

Atropine uses?

bradycardia, ventricular asystole, antidote for anticholinesterase inhibitor toxicity or poisoning, and preoperatively to reduce salivation and GI secretions

Atropine is a what?

Naturally occurring antimuscarinic

Atropine contraindications?

angle-closure glaucoma, advanced hepatic and renal dysfunction, hiatal hernia associated with reflux esophagitis, intestinal atony, obstructive GI or GU conditions, and severe ulcerative colitis

Glycopyrrolate is a what?

Synthetic antimuscarinic drug, Blocks receptor sites in the autonomic nervous system that control the production of secretions

Glycopyrrolate, uses?

preoperatively to reduce salivation and excessive secretions in the respiratory and GI tracts

Glycopyrrolate, Contraindications?

hypersensitivity, angle-closure glaucoma, myasthenia gravis, GI or GU tract obstruction, tachycardia, myocardial ischemia, hepatic disease, ulcerative colitis, and toxic megacolon

oxybutynin (Ditropan®) is a what?

Synthetic antimuscarinic drug

oxybutynin (Ditropan®), Uses:

overactive bladder and antispasmodic for neurogenic bladder associated with spinal cord injuries and congenital conditions such as spina bifida

oxybutynin (Ditropan®), Contraindications:

drug allergy, urinary or gastric retention, and uncontrolled angle-closure glaucoma

Scopolamine is a what?

Naturally occurring cholinergic blocker and one of the principal belladonna alkaloids

Scopolamine, Uses:

prevention of motion sickness and to help prevent postoperative, postanaesthesia nausea and vomiting

Scopolamine, contraindications?

angle-closure glaucoma, advanced hepatic and renal dysfunction, hiatal hernia associated with reflux esophagitis, intestinal atony, obstructive GI or GU conditions, and severe ulcerative colitis.

Scopolamine adverse effects?

drowsiness, dry mouth, and blurred vision

Scopolamine with CNS depressants cause what?

increase sedation.

tolterodine is a what?

Muscarinic receptor blocker

tolterodine, uses?

urinary frequency, urgency, and urge incontinence caused by bladder (detrusor) over-activity

tolterodine - Newer drugs

Newer drugs are associated with a much lower incidence of dry mouth, partly because of their pharmacological specificity for the bladder as opposed to the salivary glands

Nursing Implications what should we assess for?

Assess for allergies, presence of BPH, urinary retention, glaucoma, tachycardia, myocardial infarction, heart failure, hiatal hernia, and GI or GU obstruction.

Nursing Implications - how should medications be taken?

Medications should be taken exactly as prescribed to have the maximum therapeutic effect.

what may patients experience with light?

Patients may experience sensitivity to light and may want to wear dark glasses or sunglasses.

whats the antidote for atropine overdose?

physostigmine.

Nursing Implications - anticholinergics taken by older adults may cause what?

Anticholinergics taken by older adult patients may lead to higher risk for heatstroke because of the effects on heat-regulating mechanisms

Patients should report the following symptoms to their physician:

urinary hesitancy or retention, constipation, tachycardia, palpitations, tremors, confusion, sedation, hallucinations, and decreased sweating (leading to hot, dry skin).

For patients with Parkinson’s disease, monitor for therapeutic effects such as?

fewer tremors and decreased salivation and drooling

For patients with urological problems, monitor for therapeutic effects such as?

improved urinary patterns, less hypermotility, increased time between voiding