autonomic nervous system: sympathetic division

divisions of autonomic nervous system

sympathetic and parasympathetic

synthetic adrenaline

epinephrine

Sympathetic effects

dilates pupils, inhibit saliva, accelerates heartbeat, dilates bronchi, inhibits peristalsis, conversion of glycogen to glucose, inhibits bladder contractions, increases blood pressure, decreases blood flow to organs and increases blood flow to muscles

parasympathetic endogenous neurotransmitter

acetylcholine

sympathetic endogenous neurotransmitters

adrenaline, norepinephrine, dopamine

adregenic receptors

alpha-1, alpha-2, beta-1, and beta-2, (rare dopamine receptor)

Where are alpha 1 receptors located?

vascular smooth muscle, eyes, nose (mucous membranes), prostate/bladder

increased stimulation of alpha-1 receptors leads to

constriction of blood vessels and increase in blood pressure

where are alpha 2 receptors located?

eyes, presynaptic nerve terminals in the brain

Where are beta 1 receptors located?

heart, kidneys (juxtaglomerular cells), eyes

Where are beta 2 receptors found?

bronchiole smooth muscle (lungs

skeletal muscle vasculature

liver

uterine smooth muscle

Where are dopamine (D1) receptors located?

vasculature of the kidneys

Symathomimetic drugs

agonists to alpha and beta receptors that mimic (nor)epinephrine at the target site

vasopressors (class)

drugs used to increase blood pressure

Vasopressor Prototypes

epinephrine/adrenaline, phenylephrine

IV epinephrine

used for ACLS in cases of shock, hypotension, bradycardia, asystole

Sub-Q epinephrine

used with lidocaine as a local anesthetic

IM epinephrine

First-line treatment for anaphylaxis. (epipen)

inhaled epinephrine

used to treat asthma but NOT recommended for routine use for effects on HR and BP

Epinephrine mechanism of action

non selective alpha and beta agonist (binds to both types of receptors)

epinephrine beta 1 effects

positive chronotropic and ionotropic effects

positive chronotropic effect

an increase in heart rate

positive ionotropic effect

increase in the force of contraction of the heart muscle (myocardium)

epinephrine beta 2 effect

bronchodilation

epinephrine alpha 1 effect

vasoconstriction—> increased BP

epinephrine alpha 2 effect

no significant effects on the brain

adverse effects of epinephrine

hypertensive crisis, dysrhythmias, tachycardia, angina, MI, stroke, poor perfusion of extremities

nursing considerations for epinephrine

monitor HR, BP, RR, gas exchange (desired pulse ox for critical pts is generally above 90)

IV Phenylephrine

used for shock and hypotension

nasal phenylephrine

used against congestion

phenylephrine mechanism of action

selective alpha1 agonist, leads to vasoconstriction and increased blood pressure

adverse effects of phenylephrine

tachycardia, hypertension, dysrhythmias, CNS excitation and seizures, dry mouth, nausea and vomiting, anorexia, rebound nasal congestion

nursing considerations for phenylephrine

monitor blood pressure as well as HR, RR and pulse ox, dont use as a nasal decongestant for more than three days

beta-1 antagonist prototypes

includes metoprolol tartrate

Metoprolol Tartrate

used for current or history of MI, HTN, angina (chest pain), dysrhythmias, heart failure, thyroid storm (thyrotoxicosis), migraine prophylaxis, glaucoma

metoprolol tartrate mechanism of action

Relatively selectively antagonizes beta-1 adrenergic receptor of the heart which decreased HR and BP, as well as in the eyes leading to pupil constriction and lower intraocular pressure (IOP)

orthostatic hypotension (postural hypotension)

abnormally low blood pressure when the person suddenly stands up/sits up

Signs of orthostatic hypotension

light headedess, dizziness, syncope (short loss of consciousness/confusion), indicates high fall risk in geriatric patients

adverse effects of metroprolol tartrate

orthostatic hypotension, bradycardia, heart failure exacerbation, fluid retention, masking of hypoglycemic effects (particularly in diabetic patients), mood changes, sexual dysfunction (decreased libido, impotence, vaginal dryness)

cautions for metoprolol tartrate

never stop suddenly because it can lead to a heart attack

Non-selective beta blocker prototypes

propranolol, timolol, labetalol, carvedilol

propranolol function

reduces anxiety

carvedilol function

Antihypertensive, cardiac function

labetalol function

HT management in pregnant individuals

non-selective beta blockers treat

HTN, glaucoma, angina, current/history of MI, dysrythmias and heart failure symptoms of hyperthyroidism, anxiety

non-selective beta blockers mechanism of action

Block B1 receptors on the heart and can block B2 and a1 receptors

timolol

eye drops used to treat glaucoma

glaucoma

increased intraocular pressure results in damage to the retina and optic nerve with loss of vision (chronic condition)

types of glaucoma

open angle and narrow angle

mydriasis

dilation of the pupil, increases IOP

miosis

constricted pupils, decreases IOP

adverse effects of non-selective beta blockers

B1: bradycardia leading to decreased cardiac output, hypotension, precipitation of heart failure, masking s/s of hypoglycemia—> tremor and palpitations

B2: bronchoconstriction, prevents glycogenolysis in the liver—> hypoglycemia

contraindications to non-selective beta blockers

Asthma, COPD

CANNOT stop suddenly as it can lead to a heart attack

alpha 1 antagonists include

tamsulosin, prazosin

tamsulosin

relieving BPH and bladder outlet obstruction (often caused by kidney stones)

prazosin

main use is in HTN

Alpha 1 Antagonists MOA

prevents activation of alpha-1 receptors. subtypes may be located in the peripheral vascular smooth muscle or in the bladder/urethra/prostate

reflex tachycardia

temporary increase in heart rate that occurs when blood pressure falls due to anti-hypertensive medication and dilation of blood vessels

treatment of reflex tachycardia

patients can be pretreated with a beta blocker which blocks the sympathetic stimulation of the heart

adverse effects of alpha-1 antagonists

reflex tachycardia, 1st dose orthostatic hypotension, sexual dysfunction (retrograde/inhibited ejaculation), rebound HT

nursing considerations of alpha-1 antagonists

given at bed time to reduce orthostatic effects, change positions slowly, sexual dysfunction, never stop suddenly, monitor U/O and symptoms of retention