Neurological Agents: Autonomic Nervous System (ANS)

what are the 2 parts of the ANS?

sympathetic nervous system

parasympathetic nervous system

where do afferent neurons carry information to?

to the brain

where do efferent/motor neurons carry information to?

back through the spinal cord and to the effector organs

the SNS is also known as what system?

adrenergic

what are the two main NT's for the SNS?

norepinephrine and epinephrine

define sympathomimetic

adrenergic agonist

define sympatholytic

adrenergic antagonist

what response is the SNS responsible for?

fight or fight response

the PSNS is also known as what system?

cholinergic

what is the main NT of the PSNS?

acetylcholine

define parasympathomimetic

cholinergic agonist

define parasympatholytic

cholinergic antagonist

what can the PSNS do to your...

pupils?

saliva secretions?

heartbeat?

airways?

stomach activity?

gall bladder?

intestines?

bladder?

genitals?

- constrict pupils

- stimulate saliva

- slow heartbeat

- constrict airways

- stimulate activity of stomach

-inhibit release of glucose; stimulate gallbladder

- stimulate activity of intestines

- contract bladder

- promote erection of genitals

what can the SNS do to your...

pupils?

saliva secretions?

heartbeat?

airways?

stomach activity?

gall bladder?

intestines?

norepinephrine and epinephrine?

bladder?

genitals?

- dilate pupils

- inhibit salivation

- increase heart rate

- relax airways

- inhibit stomach activity

- stimulate release of glucose; inhibits gallbladder

- inhibits activity of intestines

- secretes epinephrine and norepinephrine

- relax bladder

- promote ejaculation and vaginal contraction

what are the 2 categories of receptors of the peripheral nervous system?

what are the types of receptors in those categories?

what do they respond to?

adrenergic receptors:

- respond to norepinephrine and epinephrine

- alpha 1, alpha 2, beta 1, beta 2

cholinergic receptors:

- responds to acetylcholine

- nicotinic and muscarinic receptors

what do alpha 1 receptors do to your....

blood vessels?

pupils?

bladder?

prostate?

smooth muscles in sphincters?

nasal cavity?

- can vasoconstrict arterioles and veins which leads to increase blood pressure and contractility of the heart

- causes mydriasis which is pupil dilation

- can cause contraction of smooth muscles in sphincters (stomach, intestine, bladder)

- can cause nasal decongestion

what can alpha 2 receptors do to your...

blood vessels?

smooth muscle in GI tract?

- inhibit release of norepinephrine, reduce vasoconstriction, which can decrease blood pressure

- can decrease gastrointestinal tone and motility

what are the beneficial responses of alpha 1 receptors?

- pupillary dilation/ mydriasis

- vasoconstriction of arterioles and veins to affect BP

- contraction of smooth muscles in sphincters (stomach, intestine, bladder)

- nasal decongestion

are alpha 2 receptors common pharmaceutical agents?

no, there aren't many agents

what are beneficial pharmacological responses of beta 1 receptors?

- positive inoTRope (contractility of heart)

- positive cHRonotrope ( heart rate )

- positive Dromotrope ( electrical conduction )

what are beneficial pharmacological responses of beta 2 receptors?

- bronchodilation

- relaxation of uterine contractions

- increased glycogenolysis

what receptors does epinephrine activate?

alpha 1

alpha 2

beta 1

beta 2

(aka all of them)

what receptors does ephedrine activate?

alpha 1

alpha 2

beta 1,

beta 2

what receptors does phenylephrine activate?

alpha 1

what receptors does dopamine activate?

alpha 1

beta 1

dopamine

what receptors does norepinephrine activate?

alpha 1

alpha 2

beta 1

what receptors does isoproterenol activate?

beta 1

beta 2

what receptors does dobutamine activate?

beta 1

what receptors does terbutaline activate?

beta 2

list 4 characteristics about catecholamines

give examples of catecholamines

- can produce a SNS response

- can't be taken orally

- short half life

- CANNOT cross the blood brain barrier

examples: endogenous (epinephrine, norepinephrine, dopamine)

drug sources: isoproterenol and dobutamine

list 4 characteristics about non-catecholamines

give examples of non-catecholamines

- can stimulate adrenergic receptors to cause sympathetic response

- can be take orally

- have a longer half-life than the catecholamine group

- CAN cross the blood brain barrier

ex: phenylephrine and albuterol

what are alpha 1 agonists used for?

vasoconstriction in blood vessels which can help increase BP in hypotensive pts or pts with shock

stop bleeding

and treat nasal congestion

what type of agent is phenylephrine hydrochloride?

alpha 1 agonist

what is phenylephrine hydrochloride commonly used for and what is it's mechanism of action?

commonly used for nasal decongestion

mech of action: constricts nasal blood vessels which will decrease inflammation/swollen mucous membranes in the area

what are 3 main side effects of alpha 1 activation?

- hypertension (can persistently elevate BP)

- bradycardia (reflex slowing of the heart triggered from response by baroreceptors responding to hypertension)

- necrosis at IV site with infiltration into tissues (due to vasoconstriction)

define extravasation

when a drug or fluid accidentally leaks out of a blood vessel into the surrounding tissue during intravenous (IV) administration

what are alpha 2 receptor agonists commonly used for?

-hypertension (causes vasodilation, BP will decrease)

what type of agent is clonidine hydrochloride?

alpha 2 agonist

what is clonidine hydrochloride used for?

what is it's mech of action?

what are side effects/adverse effects of using it?

- used for hypertension

mech of action: centrally acting drug that produces vasodilation by stimulating alpha 2 receptors in CNS

side effects: hypotension, orthostatic hypotension, bradycardia, dizziness, edema, dry mouth, GI distress

what are the main uses for beta 1 receptor agonists and how do they do it?

treatment of cardiac arrest caused by no cardiac output

- increases myocardial contractility, conduction, and heart rate

treatment of heart failure (failure to pump blood forward)

- increases contractility to increase CO

treatment of shock

- increase HR, force of contraction, conduction, and CO

what are side effects of beta 1 receptor activation?

- altered heart rate and rhythm (tachycardia or dysrhythmias can happen)

- angina pectoris (chest pain): can happen due to increase in cardiac oxygen demand that body can't meet

what is the mech of action of dopamine?

what can it be used for?

mech of action: primarily binds to dopamine receptors but can also stim alpha 1 and beta 1 receptors

uses: shock (will increase CO and dilate renal BV)

heart failure (to pump blood forward, med will increase myocardial contractility)

what are beta 2 receptor agonists used for?

asthma: promotes bronchodilation

preterm labor: relaxes uterine smooth muscles

what type of agent is terbutaline sulfate?

beta 2 agonist

what are the uses for terbutaline sulfate?

what is it's mechanism of action?

what are the side effects/adverse effects?

uses: to stop preterm labor

mech of action: binds to beta 2 receptors to relax uterine contraction

side effects: tremors, dizziness, headache, tachycardia, palpitations, changes in blood sugar (high or low)

what type of agent is albuterol sulfate?

beta 2 agonist

what is the use for albuterol sulfate?

what is the mech of action?

what are the side effects/adverse effects?

uses: to treat bronchospasm, asthma, bronchitis, COPD

mech of action: binds to beta 2 receptors to promote bronchodilation of lungs

side effects: tremors, dizziness, nervousness, tachycardia, palpitations, cardiac dysrhythmias

how can beta 2 activation cause hyperglycemia?

what type of patients will this effect?

promotes breakdown of glycogen into glucose which increase blood sugar

major concern for diabetic pts, insulin doses may need to be increased

what is epinephrine used for?

anaphylaxis, anaphylactic shock

bronchospasms, status asthmaticus

cardiogenic shock

what effect does epinephrine have on each adrenergic receptor?

alpha 1: can cause vasoconstriction of blood vessels (increase BP)

alpha 2: can modulate norepinephrine release

beta 1: can cause an increase in myocardial contraction, increase HR, and increase conduction of the heart (overall increase of CO)

beta 2: cause bronchodilation in the lungs

how is epinephrine administered?

topically, by injection, or by inhalation

why can't epinephrine be given orally?

catecholamines metabolize rapidly in GI tract/liver which limit the drug from reaching the systemic circulation

list side effects of epinephrine

tachycardia

hypertension

dysrhythmias

angina

insomnia

restlessness

hyperglycemia

necrosis following IV extravasation

which patients should be cautious about using epinephrine?

patients with...

hypertension

close angle glaucoma

labor/pregnancy

diabetes mellitus

what are adrenergic antagonist also called?

adrenergic blockers

sympatholytic agents

what is the action of adrenergic antagonists and how does it work?

they block effects of adrenergic NTs or agonist drugs by blocking the alpha and beta receptor sites

- by occupying the receptors the agents will block the intended response or they will inhibit the release of NTs like epinephrine and norepinephrine

what are the effects of adrenergic antagonists on alpha 1 receptors?

vasodilation

dizziness

orthostatic hypotension

reflex tachycardia

pupil constriction

suppresses ejaculation

reduces contraction of smooth muscles in bladder neck and prostate

what are the effects of adrenergic antagonists on beta 1 receptors?

reduced cardiac contractility

decreases pulse

what are the effects of adrenergic antagonists on beta 2 receptors?

bronchoconstriction

contracts uterus

inhibits glycogenolysis

leads to hypoglycemia

what does selective alpha adrenergic blockers target?

what do non-selective alpha adrenergic blockers target?

selective: alpha 1

non-selective: alpha 1 and alpha 2

what are alpha adrenergic antagonists used for?

hypertension

decreases symptoms of PVD like Raynaud's phenomenon

benign prostate hyperplasia

reversal of toxicity from alpha 1 agonist

how does alpha adrenergic antagonists treat Raynaud's phenomenon?

promotes vasodilation to the peripheral blood vessels to increase blood flow to the periphery

how does alpha adrenergic antagonists treat benign prostatic hyperplasia?

decreases contraction in smooth muscle in the bladder neck and the prostate

what type of agent is doxazosin (cardura)?

what is it used for?

what is it's mechanism of action?

alpha adrenergic antagonist

uses: hypertension and BPH

mech of action: selective to alpha 1 receptors, causes vasodilation of arterioles and veins to lower BP, and causes relaxation of bladder neck and prostatic capsule to allow an increase of urine flow from bladder

what type of agent is phentolamine mesylate?

what is the mechanism of action?

what is it used for?

where do you inject it?

alpha adrenergic antagonist

mech of action: blocks alpha 1 and alpha 2 receptors to promote vasodilation to blood vessels that may have been constricted by an alpha 1 agonist

uses: prevents necrosis following extravasation of drugs that produced alpha 1 vasoconstriction (ex: norepi or epineph)

inject into affect tissue area

list the 3 main side effects of alpha blockers and how they cause them

orthostatic hypotension: alpha blockers reduce muscle tone in venous wall, blood tends to pool when patient stands up

reflex tachycardia: increases heart rate by triggering baroreceptor reflex

can be suppressed by use of beta blockers

nasal congestion: dilates blood vessels of nasal mucosa

how do non selective beta blockers work on beta 1 and beta 2 receptors?

beta 1: decreases heart rate, cardiac contractility, and cardiac conduction

by decreasing cardiac HR, contractility, and conduction = decrease BP

blocking renin will also decrease BP

beta 2: bronchoconstriction, increase GI motility, uterine contraction, prevent liver glycogenolysis (decrease in blood sugar)

what patients should AVOID beta blockers?

COPD and Asthma patients

what type of agent is propanolol HCl?

what is it used for?

non-selective beta blocker (blocks both beta 1 and beta 2)

uses: agina, cardiac dysrhythmias, hypertension, heart failure, hyperthyroidism, migraine headaches, and stage fright

what type of agent is metropolol?

what is it used for?

selective agent only blocking beta 1

uses: blocks beta 1 to decrease HR, conduction, and contractility of heart

lowers BP and decreases renin release

low beta 2 side effects but higher dosages can cause

what is the drug of choice for patients with lung issues and/or diabetes mellitus?

selective beta 1 blockers

list side effects of beta 1 blockers

bradycardia

hypotension

dysrhythmias

headaches

dizziness

drowsiness

fatigue

GI distress

heart failure

reduced cardiac output

reduces HR and force of contraction

list side effects of beta 2 blockers

bronchoconstriction

inhibition of glycogenolysis

what are the two types of cholinergic receptors and what do they do?

muscarinic: stimulates PSNS system responses

nicotinic: contraction of skeletal muscles

what are two ways to mimic the action of ACH?

-direct acting cholinergic agonists

- indirect acting cholinergic agonists: inhibits acetylcholinesterase enzyme that breaks down ACH

what are the cholinergic agonist effects on your...

eyes?

lungs?

cardiovascular?

GI?

GU?

Glands?

- pupil constriction, increase accommodation

- bronchoconstriction, increase secretions

- decrease HR and BP, vasodilation, slow conduction of AV node

- increase tone, motility, peristalsis, and relax sphincter muscles

- increase ureter tone, contract bladder, and relax sphincter muscles, stimulates urination

- increase salivation, perspiration, and tears

what are the action of direct acting cholinergic agonists?

primarily selective to muscarinic receptors so expect side effects in these areas

(smooth muscles in heart, lungs, GI, GU, and glands)

what type of agent is bethanechol chloride?

what is it used for?

what is the mech of action?

what are the side effects?

direct acting cholinergic agonist

uses: to treat urinary retention by increasing/stimulating urination

mech of action: stimulates cholinergic receptors to promote contraction of the bladder, increases secretions and peristalsis of the GI tract, can lead to pupillary constriction and bronchoconstriction

side effects: GI distress, hypersalivation, urinary urgency and frequency, miosis, hypotension, tachycardia, and bronchospasm

what patients should be cautious about using Bethanechol chloride?

patients with...

urinary obstruction

hypotension

COPD

why are indirect acting cholinergic agonists important?

they're important for diseases like myasthenia gravis

what do ACHase inhibitors do?

BLOCK the enzyme acetylcholinesterase which can increase ACH levels in synaptic gap

what are side effects of parasympathomimetic agents?

profuse salivation and lacrimation

increased muscle tone

urinary frequency

abdominal cramping and diarrhea

bronchoconstriction

bradycardia

hypotension

what are effects of anticholinergics on you...

eyes?

lungs?

heart?

GI?

GU?

Glands?

muscles?

- dilate pupils, decrease accommodation

- bronchodilation, decrease secretions

- large doses increase HR; small doses decrease HR

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

- relax detrusor muscle, increase sphincter constriction

- decreases salivation and perspiration

- decrease tremors and rigidity of muscles

what type of agent is atropine sulfate?

what are the uses for it?

what is the mech of action?

what does the therapeutic response include?

anticholinergic agent

uses: to treat bradycardia, preop med to decrease salivary secretions and prevent HR from dropping too low

dilate pupils for eye exams/surgery

antidote for cholinergic agonists overdose or exposure to nerve agent in bioterrorism

mech of action: blocks muscarinic receptors and have little effect on nicotinic receptors (unless in high doses)

therapeutic responses: increase HR, decrease GI motility, spasms, peristalsis, salivary and gastric secretions

what is oxybutynin (ditropan) used for?

urinary tract antispasmodic

treats and overactive bladder

used for incontinence

what is dyclomine (bentyl) used for?

irritable bowel syndrome

what is scopolamine used for?

motion sickness and eye examinations

what patients should NEVER use anticholinergic agents?

patients with glaucoma

list the anticholinergic side effects

photophobia, blurred vision due to increase in intraocular pressure and contraindicated in patients with glaucoma

dry mouth and skin, decreased sweating

drowsiness, confusion, dizziness

tachycardia, palpitations, dysrhythmias, hypotension

urinary retention, impotence

abdominal distention, nausea, constipation