W3 : Flashcards
what are the effects of stimulation of å1 adrenoceptor?
the site is at blood vessels ; can be used for shock
agonist does the following :
- increase peripheral resistance
- increase BP
- mydriasis
- increase closure of internal sphincter of bladder
what are the effects of stimulation of ß1 adrenoceptor?
agonist does the following :
- tachycardia
- increase lipolysis
- increased myocardial contractility
- increase release of renin
can be used for HT failure
what are the effects of stimulation of ß2 adrenoceptor?
agonist does the following :
- vasodilation
- slightly decrease peripheral resistance
- bronchodilation
- increase muscle and liver glycogenolysis
- increase release of glucagon
- relax uterine smooth muscle (can prevent preterm delivery)
what are DIRECT acting adrenergic agonist?
these drugs act directly on å or ß receptors, producing effects similar to those that occur following stimulation of sympathetic nerves or release the hormone epinephrine from the adrenal medulla
there are two types of DIRECT acting adrenergic agonist :
- catecholemines
- noncatecholemines
epinephrine
direct acting adrenergic agonist
catecholemines
å1, å2, ß1, ß2
used in intense asthma
anaphylactic shock, etc.
dobutamine
direct acting adrenergic agonist
catecholemines
ß1
drug of choice to stimulate heart
dopamine
direct acting adrenergic agonist
catecholemines
å1, ß1
used to treat shock
phenylephrine
direct acting adrenergic agonist
noncatecholemines
å1
causes intense vasoconstriction
terbutaline
direct acting adrenergic agonist
noncatecholemines
ß2
used as bronchodilator (asthma)
albuterol
direct acting adrenergic agonist
noncatecholemines
ß2
used as bronchodilator (asthma)
salmeterol
direct acting adrenergic agonist
noncatecholemines
ß2
long acting bronchodilator
what are INDIRECT acting adrenergic agonist?
they cause norepinephrine release from presynaptic terminals or inhibit the uptake of nor-epinephrine
amphetamine
INDIRECT acting adrenergic agonist
has CNS stimulatory effects
used for narcolepsy, ADHD, appetite control
methylphenidate
same as amphetamine
INDIRECT acting adrenergic agonist
has CNS stimulatory effects
used for narcolepsy, ADHD, appetite control
what happens if a patient taking MAO-inhibitors eat lots of cheese?
- tyraminine is oxidized by MAO (manoamine oxidase)
- if patient taking MAP-inhibitors eat cheese, tyramine of cheese cannot be oxidized
- tyramine enters nerve terminal, and displaces store norepinephrine, thereby causing hypertensive crisis
[patient can carry 25mg tablets of chlorpromazine for emergency]
what are adrenergic antagonist?
these drugs bind to the adrenergic receptors and PREVENT their activation by endogenous epinephrine and norepinephrine
there are :
- å-adrenergic blocking agents (non-selective & selective)
- ß-adrenergic blocking agents (non-selective & selective)
- å & ß blockers
what are 2 families of adrenergic receptors?
and how are they further subdivided?
å adrenoceptor & ß adrenoceptor
å adrenoceptor are subdivided into two groups :
å 1 and å 2 - these are further subdivided into :
å 1A, å 1B, å 1C, å 1D & å 2A, å 2B, å 2C
MOA of non-selective å blocker (å1 and å2 blockers)?
there drugs block both å adrenergic receptors causing vasodilation and lowering blood pressure
Phenoxybenzamine
adrenergic antagonist(å1 and å2 blockers)
cause vasodilation and lower blood pressure
tx of pheochromocytoma (tumor of adrenal medulla, which produces too much epinephrine),
tx of hypertensive episodes
doxazosin
adrenergic antagonist
selective å1 blocker
tx. hypertension (can cause orthostatic hypotension
tamsulosin
adrenergic antagonist
selective å1A blocker
relaxes smooth muscle in urinary bladder neck and prostate–> improving urine flow in benign prostate hyperplasia
clonidine
adrenergic antagonist
å2 agonist (in blood vessel)
inhibits both sympathetic output from the brain and release of norepinephrine from nerve terminals–> reduce blood pressure
tx. hypertension