Question Answer
These mimic peripheral effects of the sympathetic nervous system Sympathomimetics
+ inotropic= increased muscular contraction
+ chronotropic = increased rate
What is a receptor? the site of biological activity, pharmacologic activity
Stimulation of Alpha receptors usually results in what? excitation
Stimulation of Beta 1 receptors results in? myocardial excitation
Stimulation of Beta 2 leads to what? depression of activity, bronchial and skeletal vasculature relaxation
Name the 5 Sympathomimetic drugs that are typical of all the others epinephrine, norepinephrine, isopropyl norepinephrine (isuprel), ephedrine, amphetamine
Sympathomimetics and adrenomimetics are classified into what two groups? Direct acting amines and indirect acting amines
How do direct acting amines work? they combine directly with postganglionic adrenergic receptors to cause action
3 examples of direct acting amines Epinephrine, norepinephrine, Isuprel
How do indirect acting amines work? cause most of their activity by releasing sympathetic transmitter from the postganglionic neurons
An example of an indirect acting amine is Aramine
Exceptions to rules about Alpha and Beta receptors Stimulation of Beta 1 receptors results in + HR and SV. Isuprel is an example- its effects are blocked by beta blocking/adrenolytic/sympatholytic agents
These receptors are classified as beta even though they are excitatory cardiac
GI smooth muscle receptors contain both alpha and beta receptors but what occurs? inhibition of tone
Ephinephrine(adrenaline) occurs at both _ and _ isomers. _ is 50 times as potent “l” and “d”; “l”
Epinephrine is secreted by the postganglionic sympathetic terminals and the adrenal medulla
Action of epinephrine Stimulated both alpha(in large doses) and Beta (small doses)
Cardiac effects of Epinephrine increased HR and SV (B1), Heart becomes more susceptible to arrythmias, results in increased systolic pressure
Vascular effects of Epinephrine increases PVR. Constriction of blood vessels in skin, mucosa, spleen, and kidneys d/t alpha stimulation. Dilation of coronary and skeletal muscle vessels d/t Beta effects
What happens with the blood after administration of Epi? it is redistributed to vital areas
Bronchial effects of Epi Bronchial muscle relax(Beta), mucosa constrict (alpha). Raw decreases
Eye effects from Epi pupils dilate d/t alpha receptors
GI effects of Epi muscle tone decreased d/t alpha and beta stimulation. peristalsis reduced. Sphincters are constricted(alpha)
Glandular effects of Epi Secretions decrease(alpha)
CNS effects from Epi anxiety, restlessness and weakness
Clinical uses of Epi acute episodes of Asthma, local anesthetic(vasoconstriction, increase induration), and Cardiac arrest
Preparations of Epi 1-not effective by mouth, 2-1/1000 solution used for IV and SQ use, 3-1/100 solution for inhalation
Adverse effects of Epi exaggerated therapeutic effects
Norepinephrine(Levarterenol, Levaphed):The _-isomer is usual sympathetic postganglionic transmitter l
Action of NorEpi substantial alpha effects, minimal beta effects (VERY IMPORTANT)
Cardiovascular effects of NorEpi increased systolic and diastolic BP d/t increase in vascular resistance. The heart is not directly stimulated
Clinical uses for NorEpi Shock- long used as a vasocontrictor to treat hypotension- action is on peripheral resistance
Preparation of NorEpi 1/1000 solution IV
Adverse effects of NorEpi cardiovascular injury. Local necrosis d/t extravasation of IV causing tissue vasoconstriction and skin necrosis
Isopropylnorepinephrine cardiovascular effects +inotropic and chronotropic effects. vasodilator.
Isuprel ___ pulse presure and Systolic pressure increases
Isuprel ____ Mean arterial pressure and diastolic pressure decreases
What drug is the most potent heart stimulant Isuprel
Bronchial effects of Isuprel dilate bronchi(beta 2), does not constrict mucosa(alpha)
Uses of Isuprel given SL or inhalation to athma patient, serves to stimulate myocardium with heart block until pacemaker placed
Preparation of Isuprel 1/100 and 1/200 solutions inhaltion and IV
THis is a naturally occurring catecholamine and precursor to epinephrine that has its own receptors and acts as a mixed amine Dopamine(Intropin)
Cardiovascular effects of dopamine CO increases, Peripheral resistance decreases, mean arterial pressure and HR unaltered
These drugs act directly and indirectly, have a longer duration of action, orally active, and people exhibit tachyphylaxis d/t them Ephedrine and amphetamine
Cardiovascular effects of Ephedrine slow onset, prolonged action, increase CO and PVR leading to htn
Bronchial effects of ephedrine dilates bronchi, slow, lasts longer
Eye effects of ephedrine dialtes pupils
CNS effects of ephedrine stimulates causing insomnia, restlessness
Uses of ephedrine allergic d/o, asthma, nasal congestions(clears up but may cause rebound congestion and mucosal burning), and for heart block(not usual drug of choice)
These are powerful central stimulants, often abused amphetamines(Benzadrine)
Action and use of Amphetamine Peripheral Nervous system, CNS, Barbituate poisoning, Obesity
Question Answer
Adrenergics Sympathomimetics/bronchodilators
Short acting agents- 4-6hrs -acute reversible airflow obstruction(asthma) -eg albuterol, levalbuterol etc
Long-acting agents (12hrs) -used for maintenance -control nocturnal symptoms -bronchodilation eg salmeterol, formoterol
Ultra-short(<3hrs) -racemic epinephrine -for status asthmaticus, post extubation, bronchitis.
Catecholamines hormone released by adrenal glands in a stress situation. Mimic epinephrine
Effects of catecholamines -tachycardia, hypertension, smooth muscle relaxation, glycogenesis, TREMORS and CNS stimulation