Cholinergic agonists and anticholinergics- week 2 content

The PNS facilitates

Salivation

Lactation

Urination

Defecation

What is the PNS responsible for?

-Reductions in HR and contractility to conserve energy

-Constrictions of the bronchi with increased secretions

-Pupillary constriction

-Vasodilation

-Perspiration and tear production

-Increases in neuromuscular transmission to maintain muscle strength and tone

-Detrusor muscle contracts, bladder neck relaxes and urine is released

Acetylcholine (Ach)

Neurotransmitter that communicates with receptors on the PNS

Muscarinic receptors

-Found on smooth muscles

-Muscarinic receptors are said to be cholinergic receptors

Drugs that stimulate the PNS mimic the neurotransmitter ______

Acetylcholine

Ach activity is terminated by hydrolysis with the enzyme ______

Acetylcholinesterase

Direct-acting cholinergic agonists

-Selective to site of muscarinic receptors

-Located in smooth muscles

-Pilocarpine (Pilocar) and Bethanechol chloride (Urecholine)

Pilocarpine (Pilocar)

-Direct acting cholinergic agonist that is used to constrict pupils

-Allows drainage of aqueous humor to treat glaucoma

-Administered as eyedrops to limit systemic absorption and adverse effects

Bethanechol chloride (Urecholine)

-Used to increase urination in patients suffering from urinary retention

-Could lead to systemic absorption and adverse effects related to cholinergic stimulation

Side effects of Bethanechol

-Blurred vision

-Hypotension, bradycardia, sweating

-Increased salivation and gastric acid, nausea, vomiting, diarrhea, abdominal cramps

-Bronchoconstriction

Contraindications for Bethanechol

Bradycardia, hypotension, COPD, peptic ulcer

Assessment related to direct acting cholinergic agonist: Bethanechol (Urecholine)

-Baseline vital signs

-Urine output should be greater than 1500 mL

-Hx of urinary obstruction and asthma

Nursing diagnosis r/t Bethanechol (Urecholine)

-Changes in urinary output

-Anxiety r/t wheezing

-Risk for impaired skin integrity r/t rash

-Ineffective breathing pattern r/t excess mucous secretion in lungs

Nursing interventions r/t Bethanechol (Urecholine)

-Monitor VS and I&O

-Give cholinergic agents 1 hour before or 2 hours after meals. If patient has gastric pain, give with meals

-Observe for side effects like gastric pain or cramping, diarrhea, increased salivary or bronchial secretions, bradycardia, and orthostatic hypotension

-Auscultate for rales

Antidote for Bethanechol (Urecholine)

IV atropine sulfate (0.6- 1.2 mg)

Patient teaching r/t Bethanechol (Urecholine)

-Report severe side effects, like profound dizziness or decrease in HR

-Rise slowly

-Report any difficulty in breathing as a result of respiratory distress.

Cholinesterase Inhibitors (Indirect-Acting Cholinergic agonists)

-Break down acetylcholinesterase enzyme into choline and acetic acid

-Allows Ach to accumulate and activate cholinergic receptors

-Used in glaucoma

Pyridostigmine (Mestinon)

Cholinesterase inhibitor that's used to treat multiple sclerosis

Side effects of Pyridostigmine (Mestinon)

Muscle cramps, twitching, bradycardia, increased bronchial secretions

Contraindications for Pyridostigmine (Mestinon)

-Intestinal and urinary obstruction

-Severe bradycardia

Anticholinergics (AKA Parasympatholytics)

-Agents that block Ach and the effects of the PNS

-Inhibits action of Ach by occupying Ach receptors

Effects of Anticholinergics

-Increase HR

-Decrease lung secretions

-GI: relax smooth muscle tone, decrease motility and peristalsis, decrease secretions

-GU: Relax detrusor muscle, increase bladder neck constriction

-Eye: dilate pupils

-Glands: decrease salivation and perspiration

Atropine

Anticholinergic that increases pulse, decreases motility and peristalsis, and decreases salivary secretions

Anticholinergic medications are useful for ______

-Motion sickness

-Slows GI motility and reduces gastric secretion

-Useful for travelers to prevent "sea-sickness"

-Ex) Scopolamine (Ivenex) and Meclizine hydrochloride (Antivert)

Hyoscyamine (Levsin)

-Slows GI motility and secretions

-Useful in treating patients with stomach cramps due to diarrhea

Bladder-specific anticholinergic medications

-Block Ach receptors in the GU tract to prevent bladder spasms, and thus preventing urinary incontinence

-Oxybutynin (Ditropan, Ditropan XL) and Tolterodine (Detrol, Detrol LA)

Side effects of anticholinergics

-Decrease salivation, lactation, urination, and defecation

-Tachycardia

-Monitor for: dry mouth, mucous plugging, reductions in urine and GI output, increases in HR.