Adrenergic Drugs Flashcards
Where do adrenergic drugs work?
- sympathetics alpha, beta, and D receptors
What G protein do the following receptors use?
a. alpha 1
b. alpha 2
c. beta
d. D
a. q
b. i
c. s
d. s (D1, 5); I (D2-4)
Where does alpha 1 act? role?
a. smooth muscle of BVs, pupillary dilator m., prostate, heart
b. contraction, vasoconstriction, dilates pupil, increase force of heart contraction
Where does alpha 2 act? role?
a. Postsynaptic CNS neurons, Platelets,
Adrenergic and cholinergic nerve terminals, Some vascular smooth muscle, Fat cells
b. Probably multiple, Aggregation, Inhibits transmitter release, Contraction, Inhibits lipolysis
Where does beta 1 act? role?
a. heart, JG cells
b. increase force/rate of contraction, increase renin release
Where does beta 2 act? role?
a. Respiratory, uterine and vascular smooth muscle,
Skeletal muscle, Human liver
b. Promotes smooth muscle relaxation, Promotes potassium uptake, Activates glycogenolysis and gluconeogenesis
Where does beta 3 act? role?
a. bladder, fat cells
b. relax detractor muscle, activates lipolysis
Where does D1 act? role?
a. smooth muscle
b. dilate renal BVs
Where does D2 act? role?
a. nerve endings
b. modules transmitter release
What is the role of Monoamine Oxidase (MAO)?
- leads to degradation of NE
- MAO inhibitors block the enzyme, and leave more NE available
Phenylephrine
a. receptors
b. function
c. adverse effects
d. treatment for…
a. a1 > a2
b. mydriatic, VC, increase BP
c. leads to severe bradycardia (baro R)
d. decongestant
Clonidine
a. receptors
b. function
c. treatment for…
a. a2 > a1 (esp. a 2 in lower brain stem)
b. decrease sympathetic outflow and BP, VC (with local application)
c. HTN
Epinephrine
a. receptors
b. function
c. treatment for…
a. a1 = a2; b1 = b2
b. increase glucose/FFA levels, increase HR/force of contraction/conduction velocity of AV node, increase K+ uptake in skeletal m/muscle tremor, bronchodilator/decrease secretions, increase renin release
c. emergency therapy for complete AV block and cardiac arrest
Norepinephrine
a. receptors
b. function
c. adverse effects
a. a1 =a 2; b1»_space; b2
b. VC, increased PVR/BP, but reduces HR (baro)
c. lacks b2 agonist effects
Isoproterenol
a. receptors
b. function
a. b1 = b2
b. increase CO (+ inotropic/chronotropic), VD, bronchodilator; emergency therapy for complete AV block and cardiac arrest
Dobutamine
a. receptors
b. function
c. treatment for…
a. b1 > b2
b. inotropic action
c. cariogenic shock; acute HF
*less prominent chronotropic action as compared to isoproterenol
Albuterol
a. receptors
b. function
c. treatment for…
a. b2 > b1
b. bronchodilator, relaxation of uterus
c. asthma
Dopamine
a. receptors
b. function
c. treatment for…
a. D1 = D2»_space; b1»_space; a1
b. D1 stimulates VD; D2 surpasses NE release
c. at higher doses, b1 activates in heart, and extremely high doses a1 causes VC; cariogenic shock, congetive, severe HF
Cocaine
a. action
b. result
a. inhibits re-uptake of DA and NE by clocking transporter
b. Local anesthetic properties
Phenelzine, Selegiline
a. action
b. result
a. inhibits MAO
b. Antidepressant action
Amphetamines, methylphenidate
a. action
b. result
a. inhibit re-uptake of DA and NE, increases their release, may have weak direct effect
b. 1. Marked stimulant effect on mood and alertness, Decrease appetite
2. used to tx ADHD
= both tx narcolepsy
Ephedrine
a. action
b. result
c. treatment for…
a. releasing agent and direct adrenergic receptor agonist
b. long duration of action, enters CNS as mild stimulant (similar to E in actions)
c. Nasal decongestant, Increases blood pressure, Stress incontinence in women; chronic hypotension, obesity
Tyramine
a. action
b. result
c. source
a. Releases stored NE from presynaptic adrenergic terminals (if administered parenterally); metabolized by MAO in liver
b. increase BP in patients taking MAO inhibitors
c. found in cheese, cured meats, and smoked/pickled fish
Phentolamine
a. action
b. treatment for…
c. fun fact
a. alpha 1 + 2 adrenoceptor antagonist
b. Pheochromocytoma
c. reversible, competitive antagonist
Phenoxybenzamine
a. action
b. treatment for…
c. fun fact
a. alpha 1 + 2 adrenoceptor antagonist
b. Pheochromocytoma
c. irreversible, non competitive antagonist
Prazosin
a. action
b. treatment for…
a. alpha 1 R selective antagonist
b. LUTS, HTN
Tamsulosin
a. action
b. treatment for…
a. alpha 1 R selective antagonist
b. BPH
*1A is the most important receptor subtype mediating prostate smooth
muscle contraction
Doxazosin
a. action
b. treatment for…
a. alpha 1 R selective antagonist
b. LUTS, HTN
Labetalol
a. action
b. treatment for…
c. fun fact
a. b and a antagonist
b.
c. partial agonist
Carvedilol
a. action
b. treatment for…
c. fun fact
a. b and a antagonist
b.
c. inverse agonist
Propranolol
a. action
b. treatment for…
a. b 1 and 2 blocker
b. Long-term use in post-infarction period – prolong the survival; hyperthyroidism
Pindolol
a. action
b. treatment for…
c. fun fact
a. b 1 and 2 blocker
b.
c. partial agonist
Nadolol
a. action
b. treatment for…
a. b 1 and 2 blockers
Metoprolol
a. action
b. treatment for…
c. fun fact
a. b1 blocker
b. Long-term use in post-infarction period – prolong the survival
c. inverse agonist
Betaxolol
a. action
b. treatment for…
a. b1 blocker
b. glaucoma
Acebutolol
a. action
b. treatment for…
c. fun fact
a. b1 blocker
b.
c. partial agonist
Atenolol
a. action
b. treatment for..
a. b1 blocker
What is the benefit of a beta blocker with an ISA?
- Block sympathetic effects BUT have submaximal effects of their own = a blunted sympathetic response
- Less risk for bradycardia, increase in VLDL/HDL, and other effects of beta receptor blockade
- Example: atenolol drastically drops HR, but pindolol only partially drops HR, so it’s safer
What is an ISA?
- Intrinsic Sympathomimetic Activity
- partial agonists at beta adrenergic receptors
How do beta blockers affect renin release?
inhibit it
Why do you have to taper off beta blockers?
- because while using them the body makes more beta receptors in an attempt to get a response, but these are all blocked by the drug
- with removal of the drug, there are more available receptors, and they all get activated, and have an increase sympathetic response
What are the true beta antagonist? what do they block?
- propanolol, betaxolol, nadolol, atenolol
- endogenous agonists; only work when those are present
