adrenergic
another word for sympathetic nervous system
sympathetic NTs
epinephrine (adrenal medulla) hepatic deactivation
Norepinephrine (postganglionic of sympathetic) reuptake deactivation
ACh (sympathetic sweat glands) NO MAJOR ROLE
receptor sites
Alpha (1&2)
Beta (1&2)
Alpha 1 receptors
located- eye, blood vessels, male sex organs and prostate, bladder
Activation- midrasis, vasoconstriction in BV, ejaculation and prostate contraction, and bladder contraction
Alpha 2 receptors
located- nerve terminals
control release of NE
no major role in PNS
Beta 1 receptor
located- Heart
Activation- increased heart rete and force of contraction, increased AV conduction and renin release (leads to high BP)
beta 2 receptors
located- skeletal muscles and smooth muscles on bronchioles
activation- dilates arterioles and bronchi, relaxes uterus, promotes glycogenolysis, and enhances contraction of skeletal muscles
sympathomimetics
mimic the sympathetic
How NT acts on receptor sites
1. direct binding or activation
2. indirect- promoting, inhibiting NT release, reuptake or storage
3. mixed
adrenergic agonists
1. catecholamines
2. noncatecholamines
catecholamines
adrenergic agonist
cannot be given orally, brief duration, cannot cross BBB
noncatecholamines
adrenergic agonist
given orally, longer half life, and crosses BBB
Adrenergic Drugs
dose dependent
the higher the dose, the less selective the drug becomes
Alpha 1 Activation
Adrenergic Drug effect;
? Increase force of heart contraction,
? blood pressure and cause Mydriasis (dilation of the pupil)
Adrenergic Blocking effect;
Vasodilation and Miosis (constriction of the pupil)
Example:
Epinephrine and Norepinephrine (agonists)
Alpha 1 therapeutic effects
vasoconstriction
Midriasis
Alpha 1 side effects
hypertension
tissue necrosis
bradycardia (to try to lower BP)
Alpha 2 Activation
Adrenergic Drug effect;
Inhabits release of norepinephrine and dilates blood vessels, producing hypotension (Low blood pressure)
Adrenergic Blocking effect;
NO effect on the PNS
Beta 1 Activation
Adrenergic Drug effect;
? Increases heart rate and forces of heart contraction
Adrenergic Blocking effect;
Epi and NE
? Decrease Heart rate
Beta 1 therapeutic effects
initiate contraction of heart after it stops
increase heart rate
improve force of contraction
enhance AV node
Beta 2 activation
Adrenergic Drug effect;
Dilates bronchioles and relaxes gastrointestinal tract
Adrenergic Blocking effect;
Epi & NE
Constricts Bronchioles
beta 2 therapeutic effects
lungs and uterus
bronchodilator
delay of preterm labor
beta 2 side effects
hyperglycemia (bc stimulates glycogenolysis)
tremor (enhances skeletal muscle contraction)
adrenergic antagonist (blockers)
occupy receptor sites to block binding of NT for activation
Alpha blockers (antagonists)
vasodilation
reduces contraction of bladder and prostate
Alpha blocker therapeutic effects
treat hypertension
reverse toxicity caused by alpha 1 agonists
treat pheochromocytoma (tumor of adrenal gland --> outpouring of epi)
treat Raynaud's disease (bc vasodilation)
relieves BPH (bc less contraction of prostate)
Alpha blockers side effects
Orthostatic hypotension
tachycardia
nasal congestion
inhibition of ejaculation
promotion of Na and H2O retention
Beta Antagonists (blockers)
three subgroups:
1. (1st generation) nonselective 2. (2nd generation)cadioselective 3. (3rd generation) dilate blood vessels but can be selective or nonselective
beta blockers therapeutic effects
reduce heart rate,
reduce force of contraction,
reduce AV node,
treat angina,
treat hypertension,
treat arrhythmias,
treat myocardial infarctions,
treat hyperthyroidism,
stage fright,
glaucoma
Adverse effects of Beta 1 blockers
bradycardia
reduced cardiac output
AV node blockade
rebound cardiac excitation
Adverse effects of beta 2 block
bronchoconstriction (bad for asthmatics)
inhibition of glycogenesis (bad for diabetic)
nonspecific beta blockers may bind to beta 1 receptor sites
high doses of beta 1 blockers can block beta 2 receptors
Epinephrine
Adrenergic agonists - Sympathomimetic
Nonselective activator of all receptors (Alpha1, Beta1 and Beta2)
? Heart rate
? Cardiac output
Constriction of blood vessel to skin
Dilation of bronchioles
Dilation of blood vessels to muscles
Emergency Drug; cardiac
Isoproterenol
Adrenergic Agonists - Sympathomimetic
Selective for beta receptors (Beta1, Beta2)
Treats Bronchodiliation
Dopamine
Adrenergic Agonists - Sympathomimetic
Selective for dopamine receptors
will activate (Alpha 1 and Beta 1 at higher doses)
Treats Shock, Congestive Heart Failure
Dobutamine
Adrenergic Agonists
Selective adrenergic drug for Beta 1
Treat Heart Failure
albuterol
selective for beta 2
salmeterol
selective for beta 2
tamsulosin hydrochloride
adrenergic antagonist
alpha 1
doxazosin
adrenergic antagonist
alpha 1
Propranolol
Adrenergic Blocking Agents - Sympatholytic
Blocks Beta1, Beta2 receptors
Treats: Cardiac, Arrhythmias, Cardiac Disease, Antispasmodic
metroprolol
beta 1 cardioselective
Phenylpropanolamine (Prion)
Nonselective Adrenergic drug that affects Alpha1, Beta1 receptors
Treat Incontinence in dogs
Yohimbine (Yobine)
Adrenergic Blocking Agents - Sympatholytic
Blocks Alpha1
Used to treat OD of Xylazine admin toxic effects of antiparasitic drug Amitraz
SE: CNS stimulation, muscle tremors, salivation.
It is a stimulant with aphrodisiac and mild MAOI effects that primaril