Week 2 Adrenergic And Adrenergic Blockers Flashcards
Adrenergic blockers
- deal with parasympathetic system
- neurotransmitter is acetylcholine
Alpha-1 receptor
-heart:increases force of contraction •vasoconstriction=⬆️ BP -pupil dilation -decrease saliva -increase bladder relaxation -increase prostrate contraction
Alpha-2
Inhibits the release of norepinephrine
- decreases blood pressure(vasodilation)
- decreases gastric motility and tone
Beta-1
- increases HR and force of contraction
- kidney increases renin&angiotensin=⬆️BP
Beta-2
- bronchial dilation
- decreased GI tone and motility
- promotes uterine relaxation
- activates glycogenesis in liver which raises blood sugar
Alpha-1 receptors location
-blood vessels, eyes(pupil dilation, bladder, prostate
Aloha-2 receptor location
- located in postganglionic sympathetic nerve endings
- when stimulated they inhibit the release of norepinephrine
- leading to a decrease in vasoconstriction
Beta-1 receptor location
- heart and kidneys
- increased heart contraction, increased heart rate
Beta-2 receptor location
- found mostly in smooth muscle of lungs, GI tract, liver, uterine muscle.
- lungs:bronchodilation
- decreases peristalsis
- activation of glycogenesis
- decreased uterine contraction
Inactivation of neurotransmitters
- Reuptake
- Enzyme degradation
- MAO &COMT 2 enzymes that inactivate norepinephrine - diffusion away from transmitter
Direct acting sympathomimetics
-directly stimulate epinephrine and norepinephrine
Indirect acting sympathomimetics
- amphetamine
- stimulates neurons to produce more neurotransmitter
Mixed acting sympathomimetics
- both direct and indirect
- stimulates the adrenergic sites and stimulate the release of norepinephrine from terminal nerve ending
Epinephrine(adrenalin)
- class: sympathomimetic,adrenergic agonists
- acts on: alpha-1,beta-2,beta-2
- quick onset, short duration of action
- contraindicated by cardiac dysrhythmias and pregnancy
- TE treat: allergic reaction, anaphylaxis, bronchospasm
Dopamine
- alpha-1 increases BP
- beta-1 increases HR
-typically used after cardiac arrest to stimulate heart
Phenylphrine (neo-synephrine)
- OTC allergy spray
- alpha 1 only
- benefit IV: increases BP without increasing HR
- if overused as nasal spray you get rebound congestion and causes a systemic response increasing BP
Adrenergic
- deal w/sympathetic nervous system
- neurotransmitter is epinephrine
Norepinephrine (levophed)
- synthetic form that only stimulates alpha-1 and Beta-1(increased BP,HR)
- used in treatment of shock
- potent vasoconstrictor
- antidote is regitine
- given IV
Pseudo ephedrine(sudafed)
- stimulates alpha-1 and beta-1
- decongestant
Terbutaline (brethine)
- stimulates beta-2
- relaxation of uterine muscle
Albuterol(Proventil)
- selective beta-2
- bronchodilation
- wide therapeutic range
- at high doses can stimulate beta-1
- given po,SR,neb, or inhaler
Common adrenergic side effects
Hypertension Tachycardia Palpating Urinary retention Dysrhythmias Pulmonary edema
Nursing actions with adrenergics
- assess vitals,urine output, breath sounds
- correct hypotension before giving
- if extravasation occurs use regitine
Adrenergic blockers(sympatholytics)
-drugs that block the effects of the adrenergic transmitter
