Adrenergic drugs Flashcards
Drugs and MOA of alpha 2 receptor agonists.
Clonidine and Methyldopa- activation of a2 rors decreasing release of NE. For HTN
These drugs constrict smooth muscles such as pupillary dilator, prostate GI tract, bladder, pilomotor and uterus) Inc ♥️ contract. and drug examples with indications.
glycogenolysis, gluconeogenesis
Alpha-1 agonists:
E- septic/anaphylactic shock
Midodrine- orthostatic hypotension
Phenylephrine- nasal decongestant
They increase ♥️ force and rate, renin secretion from kidneys and ghrelin secretion from stomach. Drugs and indications.
Beta 1 agonists:
Dobutamine and Iso, Prenalterol- CHF, cardiogenic shock
For asthma:
SABA: Terbutaline, salbutamol, prenalterol
LABA: salmeterol, formoterol
Beta 2 agonists: Bronchodilation, increases K uptake in muscles, glycogenolysis, gluconeogenesis, lipolysis
Sympathomimetics SAR
- C3 and C4 aryl OHs elevate potency but dec. oral bioav and duration of action
- Larger the alkyl subs. on amino grp, greater Beta selectivity
- alpha-C subs. prolongs DOA by interfering w dg Ox’n by MAO
- Beta OH facilitates ror activation
As you increase DOPA dose what happens with A and B effects
With Epinephrine dose?
DOPA: vasoconstriction (b-effect)
VD (a-effect)
E: VD (b)
VC (a)
Action for B3 agonists and main location, drug example and indication.
Adipose tissue and bladder: relaxes detrusor muscle, lipolysis and thermogenesis
Mirabegron for overactive bladder
Alpha antagonists for HTN and BPH drug examples.
Alpha 1 ant: Prazosin (shortest) Tera Doxa (longest and Tamsulosin
Used for Pheochromocytoma
A1 and 2: Phentolamine
Irrev ant: Phenoxybenzamine
A2 agonist with SE rebound HTN
Clonidine
A1 antagonist with SE syncope
Terazosin
Mostly replaced by phosphodiesterase inhibitors for erectile dysfunction.
Alpha 1 antagonists
Non selective Beta blockers.
B and A blockers.
- Nado, Timo, Propranolol
- Carve and Labetalol
B blockers with Intrinsic Sympathomimetic Activity
Acebutalol, Pindolol
About SNS (differentiating from PSNS)
Originates from thoracic and lumbar regions
short preganglionic, long post nerve fibers
ganglia near spinal cord
NT: E NE DOPA ACh
Adrenergic receptors and classifications.
a1- postsynaptic in the SNS
a2- pre in the SNS and post in the brain
b1- in the heart
b2- sympathetically innervated structures
SAR. What ring system does a-blockers contain attached to a piperazine ring?
4-amino-6-7-dimethylxoquinazoline ring system
SAR. Reduction of this ring of Prazosin to the ring of Terazosin alters metabolism rate.
Reduction of furan ring of Prazosin to the tetrahydrofuran ring of Terazosin increases DOA by altering metabolism rate.
BB drugs that are renally cleared?
Cleared by the liver?
- Hydrophilic: Ateno, Nadolol
- Lipophilic: Propra, Pindo, Metoprolol (hepatic elimination)
The only BB that can be used for anxiety, CNS SEs insomia, depression and vivid dreams. Why?
Propranolol can penetrate into the CNS
These BB drugs block b2 rors in ciliary muscles (produces aqueous humor)
Timo, Betaxo, Metoprolol
