Ch. 18: Adrenergic drugs Flashcards
Describe the classification of the nervous system
Nervous system –> CNS and PNS
CNS –> brain + spinal cord
PNS –> somatic and ANS
ANS –> SNS and PSNS
Target receptor sites for catecholamines (NEP and EP) are called ___________
adrenergic receptors
What are the 2 main groups of adrenergic receptors? What is the difference between the receptors?
Alpha and Beta (1 and 2)
Alpha 1 - mostly on blood vessels
Beta 1 - mostly heart
Beta 2 - mostly lungs (bronchioles) + arterioles, visceral organs
What are the main NT(‘s) for the SNS and PSNS?
SNS: EP and NEP
PSNS: DA
Catecholamines are metabolized by 2 enzymes: ___________, and ___________
Monoamine oxidase (MAO) - breaks down catecholamines in the nerve ending catechol O-methyltransferase (COMT) - breaks down catecholamines at the synaptic cleft
Explain the difference between direct-acting and indirect-acting sympathomimetics
direct-acting binds directly to receptor to cause the physiological response e.g. epinephrine
indirect-acting causes the release of the catecholamine from the vesicles in the nerve end bulb, which then binds to receptors and causes a physiological response e.g. amphetamines
How does a mixed-acting sympathomimetics stimulate the receptor?
by binding to it and indirectly stimulating the receptor to release the neurotransmitter in the vesicles e.g. Ephedrine
Is Salbutamol an adrenergic drug? Explain.
Salbutamol is a noncatecholamine adrenergic ie. structrually dissimilar to endogenous catecholamines so longer duration of action than endogenous or synthetic catecholamines
What is the MAIN drug effect of alpha 1 adrenergic drugs?
smooth muscle contraction –> vasoconstriction
What is the main drug effect of alpha 2 adrenergics?
no physiologically or pharmacologically significant
What are the 3 main drug effects of Beta-1 adrenergics?
1) positive inotropic effect
2) positive chronotropic effect
3) increase in conduction of cardiac electrical nerve impulses through the AV node (positive dromotropic effect)
What are the main drug effects of Beta-2 adrenergics?
relaxation of bronchi –> bronchodilation
relaxation of the uterus
increased glycogenolysis in the liver
increase in renin secretion in the kidneys
T/F: the topical adrenergics applied to the surface of the eye are called ophthalmics and can be used to reduce intraocular pressure and dilate the pupils (mydriasis)
True
What are the 2 most life-threatening toxic effects of adrenergic drugs?
seizures and intracranial bleeding
T/F: the antidote for adrenergic drug overdose is acetylcholine
False - adrenergics have very short half-lives, so stopping the drug should quickly cause the symptoms to subside
