Adrenergic drugs Flashcards
Effects of Epi on vascular tone
Increase systolic BP
May decrease disatolic BP and total PVR
Vascular constriction in skin vessels and mucous membranes
Vascular dilation or constriction in skeletal muscle
What are the non-selective α-adrenoreceptor antagonists?
(direct acting antiadrenergic drugs)
Phentolamine
Phenoxybenzamine
Effects of beta-blockers on blood vessels
Initial rise in PVR
Chronic use leads to a decrease in PVR which lowers BP in hypertensive individuals
What direct acting adrenomimetics are mixed alpha and beta agonists?
Norephinephrine (Levophed**)
Epinephrine (Adrenalin)
Effects of isoproterenol
Positive inotropic and chronotropic action, increases CO (β1)
Vasodilator, decreases arterial pressure (β2)
Bronchodilation (β2)
Effects of Clonidine
Decreases sympathetic outflow, reduces BP, bradycardia by acting on the lower brainstem area
Regulates release of NE by binding to presynaptic α2 receptors
Effects of beta-blockers on the respiratory system
increase airway resistance
α2 receptor type activation utilizes what type of GPCR?
Gi
Effects of Epinephrine on cardiac function
Increase force of contraction
Increase HR
Increase conduction velocity of AV node
What direct acting adrenomimetics are beta agonists?
Dobutamine β1 > β2
Isoproterenol β1 = β2
Albuterol (Ventolin) β2 > β1
Locations of α1 adrenoreceptors
What is the outcome of receptor activation?
Most vascular smooth m.
Pupillary dilator m.
Prostate
Heart
Contraction
Effects of Dopamine
D1 receptors lead to vasodilation
D2 receptors suppress NE release
What dopamine receptors utilize Gi GPCRs?
D2, D3 and D4
What drug is an inhibitor of norephinephrine release?(indirect acting antiadrenergic drugs)
Guanethidine
What are the non-selective β-blockers? (direct acting antiadrenergic drugs)
Propranolol
Pindolol
Nadolol
What are the α1 selective α-adrenoreceptor antagonists?
Prazosin
Tamsulosin
Doxazosin
Locations of α2 adrenoreceptors (action)
Postsynaptic CNS neurons
Platelets (aggregation)
Adrenergic OR cholinergic nerve terminals (inhibits NT release)
Some vascular smooth m.
Fat cells (inhibits lipolysis)
Location of β2 adrenoreceptors
Respiratory, uterine and vascular smooth m. (relaxation)
Skeletal m. (K+ uptake)
Human liver (activate gluconeogenesis and glycogenolysis)
Effects of phenylephrine
mydriatic and decongestant
severe vasoconstriction and subsequent increase in BP
severe bradycardia
Location of β1 adrenoreceptors (action)
Heart ( + inotropy, + chronotropy)
Juxtaglomerular cells (increase renin release)
Indirect adrenomimetic that is a releasing agent and a direct adrenergic receptor agonist
Ephedrine
What are the mixed blockers?
(direct acting antiadrenergic drugs)
Labetalol (β and α1 antagonist)
Carvedilol (β and α1 antagonist)
Adverse effects of adrenergic agonists
Elevated BP
Increased cardiac work leading to MI or HF
Sudden death d/t arrhythmias
Insomnia
Lack of appetite
Anxiety
Psychoses, convulsions
Hemorrhagic stroke
Effects of Epi on respiratory system
Relaxes bronchial smooth m. (β2)
Decreases bronchial secretion and congestion within bronchial mucosa (α1)
Effects of Phenelzine and Selegiline
Inhibit MAO and increase NE stores in CNS
Antidepressant action
Effects of Epi on skeletal m.
Tremor (β2)
Increase K+ uptake (β2)
Indirect acting adrenomimetics that reverse NE and DA uptake mechanisms and increase their release
Amphetamines
Methylphenidate (Ritalin)
Tyramine (a byproduct of tyrosine metabolism, not a drug)
β receptor type activation utilizes what type of GPCR?
Gs
Location of D1 receptors
Smooth m. (dilates renal blood vessels)
Adverse effects of alpha antagonists
Postural HoTN
Tachycardia
Retention of fluid and salt
Impaird ejaculation
Nasal stuffiness
Clinical use of beta blockers
HTN
Angina pectoris
MI
Cardiac arrhythmias
HF
Glaucoma
Hyperthyroidism
What is the receptor preference for phenylephrine?
α1 > α2 >>>> β
Effects of Dobutamine
Potent inotropic action
Has α1 receptor activity (can act as an agonist or antagonist)
Effects of Tyramine
Releases stored NE from presynaptic terminals
May increase BP in patients taking MAO inhibitors
Adverse effects of beta-blockers
Sedation
Sleep disturbances
Depression
Increase airway resistance
Bronchospasms
Decrease HR and contractility
Hypoglycemic episodes
Clinical use of alpha antagonists
Pheochromocytoma
Chronic (essential) HTN
ED
BPH
Effects on beta-blockers on the heart
Negative inotropic effect
Negative chronotropic effect
Slow AV node conduction
What dopamine receptors utilize Gs GPCRs?
D1 and D5
What are the β1 selective β-adrenoreceptor blockers?(direct acting antiadrenergic drugs)
Metoprolol
Betaxolol
Acebutolol
Atenolol
What direct acting adrenomimetics are dopamine agonists?
Dopamine
What drug is an inhibitor of tyrosine hydroxylase? (indirect acting antiadrenergic drugs)
Metyrosine
What drug is an indirect acting adrenomimetic that inhibits re-uptake of dopamine and norepinephrine?
Cocaine
Effects of NE
Reduces HR
Potent vasoconstrictor
NO bronchodilation and vasodilation
Increases PVR and BP
Location of D2 receptors
Nerve endings (modulate NT release)
What is the receptor preference of NE?
α1 = α2
β1 >> β2
What drugs are indirect acting adrenomimetics that inhibit MAO (monoamine oxidase)?
Selegiline
Phenelzine
Effects of Albuterol
Bronchodilation
Relaxation of uterus
α1 receptor type activation utilizes what type of GPCR?
Gq
What direct acting adrenomimetics are alpha agonists?
Phenylephrine (α1 > α2)
Clonidine (α2 > α1)
Location of β3 adrenoreceptors
Bladder (relaxes detrusor m.)
Fat cells (activation of lipolysis)
What is the receptor preference for Clonidine?
α2 > α1 >>>> β
Effects of beta-blockers on the eye
Reduced intraocular pressure through reduced production of aqueous humor
Clinical use of Ephedrine
Nasal decongestant
Increase BP
Stress incontinence in women
Clinical use of adrenergic agonists
Hypotensive emergencies
Chronic hypotension
Cardiogenic shock
HF
HTN
Cardiac arrest or complete AV block
Narcolepsy
ADHD
Obesity
Asthma
Decongestion
Anaphylaxis
