Drugs Affecting the Autonomic Nervous System Adrenergic and Cholinergic Agents and Blockers

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Some Definitions A paradoxical response is an opposite response An agonist imitates the action of the neurotransmitter. An antagonist inhibits or blocks the action of the neurotransmitter. Example: –An adrenergic agent (agonist) like epinephrine vasoconstricts and stimulates cardiac activity, and bronchodialates. An adrenergic blocker (antagonist)(also called alpha or beta blockers) like sotolol vasodialates and decreases cardiac activity, and causes bronchoconstriction.

The Major transmitters of the Autonomic Nervous system (ANS) 1. Norepinephrine is an Adrenergic (a catecholamine) 2. Acetylcholine is a Cholinergic (a non- catecholamine)

Cholinergic Agents (Agonists) Anticholinergic Agents (Antagonists) Cholinergic agents produce effects similar to acetylcholine. Anticholinergic agents inhibit or block effects of acetylcholine. Example: –Cholinergic agents like neostigmine improve muscle contraction and increase salivation. –Anticholinergic agents like atropine decrease contractions and salivation.

Uses for Cholinergics To________________pupils (myosis) –__________intraoccular pressure _____________gastric emptying _____________bladder emptying _____________muscle contractions

Remembering the Effects of Cholinergic Agents S - salivation L – lacrimation U – urination D –diarrhea G – GI motility E - emesis Mild is the desired effect Severe is adverse effects, “cholinergic poisoning”

Uses for Anticholinergics Decrease muscle ____________________ ______________heart rate in low doses ______________heart rate in high doses ______________secretions ______________ bronchioles

Remembering the side effects of Anti-cholinergic Agents (Cholinergic blockers) Anti means against (not or can’t) Effects of Anticholinergics are that the patient: –Can’t see (pupil dilation and dryness) –Can’t pee (decreased bladder contraction=retention –Can’t spit (decreased salivation/secretions) –Can’t sh** (move their bowels) Modified from Nursing Pharmacology Incredibly Easy (2004)

Important Precautions Cholinergic Agents –Monitor for cardiovascular and respiratory changes. –Teach safety precautions related to orthostatic hypotension. Anticholinergic agents –Monitor and treat for urinary retention, constipation and orthostatic hypotension.

Uses for Adrenergic Agents Adrenalin – think GO! Broncho_________________ Positive inotropic_____________________ Positive chronotropic__________________ Mydriasis___________________________ ______________vessels to essential organs

Important Precautions Adrenergic agents: Expect more side effects with increased doses. Use nrsg. measures to ensure safety with orthostatic hypotension. Monitor and report cardiovascular changes (Vital signs).

Uses for Adrenergic Blockers Alpha – vasodilate or vasoconstrict Beta – vasodilates, constricts bronchioles, bradycardia Atropine reverses bradycardia from overdose

Important Precautions Adrenergic Blocking Agents –Expect increases side effects with increased doses. Discontinue over 2 weeks (taper down) because sudden stoppage=exacerbation or rebound angina, tachycardia or myocardial infarction.

Disclaimer This workforce solution was funded by a grant awarded under the President’s Community-Based Job Training Grants as implemented by the U.S. Department of Labor’s Employment and Training Administration. The solution was created by the grantee and does not necessarily reflect the official position of the U.S. Department of Labor. The Department of Labor makes no guarantees, warranties, or assurances of any kind, express or implied, with respect to such information, including any information on linked sites and including, but not limited to, accuracy of the information or its completeness, timeliness, usefulness, adequacy, continued availability, or ownership. This solution is copyrighted by the institution that created it. Internal use by an organization and/or personal use by an individual for non-commercial purposes is permissible. All other uses require the prior authorization of the copyright owner.