Autonomic Nervous System

Sympathetic (Adrenergic) Parasympathetic (Cholinergic) Have a balancing effect

Neurotransmitters

Acetycholine (ACH) Norepinephrine (NE) Epinephrine Dopamine

Receptors

Alpha 1 & 2 Beta 1 & 2 Muscarinic Nicotinie

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