Adrenergics (Konorev) Flashcards
Direct acting adrenomimetics come in three broad flavors. What are they?
Alpha agonists
Mixed alpha and beta agonists
Beta agonists
What are the alpha agonists?
Phenylephrine (Neo-Synephrine) (a1>a2>>>B)
Clonidine (Catapres) (a2>a1>>>>B)
What are the mixed alpha and beta agonists?
Norepinephrine (Levophed) (a1=a2; B1>>>B2)
Epinephrine (Adrenalin) (a1=a2; B1=B2)
What are the Beta agonists?
Dobutamine (Dobutrex) (B1>B2>>>>a)
Isoproterenol (Isuprel) (B1=B2>>>a)
Albuterol (Ventolin) (B2>B1>>>a)
Indirect Adrenomimetics come in four flavors. What are they?
Reuptake inhibitors of DA and NE
Inhibitors of MAO
Reverse NE and DA uptake mechanisms and increase release
Releasing agent and direct adrenergic receptor agonist
What are the DA and NE reuptake inhibitors?
Cocaine
What are the inhibitors of MAO?
Selegiline (Eldepryl)
Phenelzine (Nardil)
What drugs reverse NE and DA uptake mechanisms and increase their release?
Amphetmines
Methyphenidate (Ritalin)
Tyramine (not a drug)
What drugs are releasing agents AND direct adrenergic receptor agonists?
Ephedrine
What are the two targets of adrenergic drugs?
Sympathetic cholinergic terminals at the target site (NE or DA)
Examples: Cardiac and smooth muscle, glands, nerve terminals (NE); renal vascular smooth muscle (DA).
What is the primary role of adrenergic drugs?
Modulate adrenergic transmission and primarily control the function of sympathetic nervous system
What is the effect of drugs that activate adrenergic transmission?
AKA adrenomimetics or sympathomimetics
These mimic/promote the effects of NE, epinephrine, DA, at adrenergic receptors in the sympathetic NS
What is the effect of drugs that inhibit adrenergic transmission?
AKA sympatholytics/antiadrenergics
These prevent the effects of NE/DA/epinephrine at adrenergic receptors in the sympathetic NS
Direct acting adrenergic drugs produce their effects how?
By interacting with adrenergic receptors
either: adrenergic receptor agonists or antagonists
Indirect acting adrenergic drugs produce their effects how?
By increasing or reducing the concentration of NE at target receptors
This works by altering NTM concentration at the target site
MAO inhibitors, reuptake blockers, and releasing agents all take place where?
at the presynaptic neuron (reuptake blockers and MAO inhibitors) and in the synapse (releasing agents)
These are all indirect acting
Adrenergic receptor agonists take place where?
At the post synaptic neuron
these are direct acting
What are the effects of epinephrine on cardiac function?
Acts on B1
Increases force of contraction (positive inotropic)
increase HR
increases conduction velocity at AV node
What are the effects of Epinephrine on vascular tone?
Acts on B2 and a1
increases systolic BP
may decrease diastolic BP and TPVR
MAP unchanged
Note: many different receptor types in vascular beds
What other tissues and receptor types can Epinephrine effect?
skin vessels and mucous membranes-mostly a1
skeletal muscle-a1 and B2
renal and cerebral-D1 and a1
What are the effects of epineprhine on the respiratory system?
relaces bronchial muscle at B2
decreases secretions and congestion in mucosa at a1
What are the effects of epinephrine on skeletal muscles?
causes muscle tremor at B2
increases K uptake at B2
promotes hypokalemia and decreases K excretion by kidney
What are the effects of epinephrine on serum concentrations of glucose/FFA, renin?
Enhances liver glycogenolysis and gluconeogenesis (B2)
increases FFA in blood (B)
increases renin release (B1)
What are the effects of NE?
a1=a2; B1>>B2
- stimulates cardiac muscle, reduces HR
- vasoconstrictor
- lacks B2 agonist effects, no bronchodilation or vasodilation
- increases PVR and BP
- role of baroreflex