autonomic nervous system sympathetic (adrenergic) parasympathetic (cholinergic) have a balancing...
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Autonomic Nervous System
Sympathetic (Adrenergic) Parasympathetic (Cholinergic) Have a balancing effect
Sympathetic Response
Increase HR Increase RR Increase metabolic rate Increase fat & glycogen breakdown Pupillary dilation Smooth muscle vasoconstriction Skeletal & cardiac muscle vasodilation Decrease GI activity Bronchial relaxation
Parasympathetic Response
Decrease HR Decrease RR Increase digestion & elimination Increase GI tone Bronchial constriction Pupillary constriction
Cholinergic Agonist (Direct Acting)
Stimulates cholinergic receptors bethanechol chloride (Duvoid, Urecholine)
* decreases urinary retention *antidote is atropine
pilocarpine (Pilocar) * increases outflow aqueous humor (open angle glaucoma) * pupillary constriction (miosis) & decrease visual acuity
*headache
Nicotine
Stimulates nicotine receptors Used for cessation of tobacco
smoking Cannot smoke when using patch
Antichoinesterase (Indirect-acting Cholinergic Agonists
Inhibits enzyme acetlycholinesterase
Results in decrease destruction of ACH
Which results in increase cholinergic action
Neostigmine (prostigmin)
Cholinergic Blockers (anticholergic)
Interrupts parasympathetic nerve impulses
Relaxes GI & urinary tract muscles & decrease GI secretions
Counteracts bronchospasm & decrease respiratory secretions
Decrease salivation Blocks cardiac vagal inhibitions
Atropine(cholinergic antagonist)
Blocks actions of ACH at muscarinic receptors
blocks vagal effects of SA node (tx bradycardia)
preoperative - decrease salivation & respiratory tract secretions
bronchodilator watch for tachycardia, urinary retention,
constipation, dry mouth
Scopolamine
Produces CNS depression with sedative & tranquilizing effects
Used to tx motion sickness
Anticholinergic Overdose
“mad as a hatter (CNS psychotic effect), dry as a bone (salivary), red as a bat (peripheral vasodilation), & blind as a bat (mydriasis)
Adrenergic Receptors
Alpha-1 & alpha-2 are differentiated by location on nerve, alpha -1 causes vasoconstriction
Beta - 1 primarily located in heart, causes cardiac stimulation
Beta - 2 located in smooth muscle of bronchioles, arterioles and visceral organs, relaxation of bronchial & GI
Side effects - alpha & beta may have headache, insomnia, restlessness, tachycardia, hypertension, N&V
Summary with receptors
Alpha - 1 = vasoconstriction beta - 1 = cardiac stimulation beta - 2 = bronchiole dilation
Alpha-1 Adrenergic Agonist
Phenylephrine: most common use is as decongestant, treat nasal congestion
Side effects: sleep disturbances, headache
Epinephrine (nonselective) (Adrenergic Agonist)
Increases heart rate & CO Increase in blood sugar Bronchiole dilation Indicated for anaphylaxis,
cardiac arrest, asthma
Beta Adrenergic Agonist
Isoproterenal (Isuprel) Increase contractility & heart rate Bronchodilator Indicated in asthma, bradycardia,
cardiac arrest Dopamine (Intropin) Dobutamine (Dobutrex) Proventil & Brethine, respiratory,
bronchodilators
Alpha Adrenergic Antagonist
Disrupts sympathetic response Relaxation of vascular smooth
muscle, peripheral vasodilation & decrease BP
prazosin (Minipress) Used for hypertension, angina,
peripheral vascular disorders Watch for orthostatic hypotension
Beta Adrenergic Blockers (antagonist)
Prevents SNS stimulation decrease peripheral vascular
resistance, decrease BP, decrease CO, decrease HR
Used to tx hypertension, angina, arrhythmias
Beta Blockers
Need to know whether cardioselective or nonselective
Beta - 1 blockers will decrease myocardial contractility& HR, Lopressor (metoprolol) & Tenormin (atenolol)
Nonselective - blocks beta - 1 and beta -2 which causes above & bronchiole constriction
Propranolol (Inderal)Nonselective Beta Blocker
Important to ask if history of asthma, bronchitis, etc.
Decrease HR so must check rate prior to giving
client may experience decrease libido or impotence
watch for orthostatic hypotension
Combined blocker
Carvedilol (Coreg) Combined alpha and beta blocker Frequently administered with other
antihypertensive agents. Watch for orthostatic hypotension
& bradycardia