11 04 2014 Adrenergic Agonists and Antagonists Flashcards
Name of drugs that mimic SNS response vs. drugs that go against SNS response
Agonists: Sympathomimetics, adrenomimetics
Antagonists: Sympatholytics
Epinephrine
Adrenergic Agonist
alpha 1 = alpha 2 , Beta 1= B2
Norepinephrine
Adrenergic Agonist
Alpha 1= alpha 2; Beta 1»» B2
Used (uncommonly) for pressor effects
Isoproterenol
Adrenergic Agonist
Beta 1 = Beta 2»_space;»> alpha
Used mostly for heart stimulation in bradycardia or heart block (direct and reflex from beta 2 effects)
Dobutamine
Adrenergic Agonist
Beta 1 > Beta 2»_space;»»> alpha
(+) inotropic effects more prominent than (+) chronotropic effects ( HR)
- used in congestive heart failure
Dopamine
Adrenergic Agonist
D1 = D2»_space;»> beta 1» alpha
Vasodilation of renal, mesenteric, and coronary beds
* dose dependent. If go too high you can cause severe vasoconstriction = ischemia of peripheral tissues
Use: heart stimulation with positive effects on renal output
Who are the catecholamines
Epinephrine, Norepinephrine, Isoproterenol, Dobutamine, Dopamine
All work directly on receptor
Who are the direct noncatecholamines?
Phenylephrine
Clonidine
Albuterol, ritodrine
Phenylephrine
Noncatecholamine– Direct
Alpha 1 > Alpha 2»_space;» Beta
Vasoconstrictive effects used to treat hypo tensions, shock
nasal decongestion (topical), ophthalmic effect (topical) - mydriasis (dilation of pupil)
Clonidine
Noncatecholamine– Direct
Alpha 2 > alpha 1»_space;»» Beta
Penetrates CNS, inhibits SNS output
= Hypotension, bradycardia, sedation
Used in hypertension
Also used in deminish craving in narcotic, alcohol, and nicotine withdrawal
Albuterol, ritodrine
Noncatecholamine– Direct
Beta 2»_space; Beta 1»_space;»» alpha
- Asthma, COPD for bronchodilation
- Inhalers minimize systemic effects
- uterine muscle relaxant to delay preterm labor (benefits?)
Who are the Noncatecholamine– Indirect ??
Amphetamine, methylphenidate
Tyramine (when MAO inhibitor present)
Cocaine
( alpha and beta, typically like NE)
Who are the mixed Noncatecholamines
Ephedrine
Pseudeoephedrine
(indirect plus direct alpha and beta)
Therapeutic uses of Epinephrine
- Anaphylactic shock ( bronchioconstriction, hypotensions and vasucular collapse, angioedema) ( via alpha and beta)
- Acute asthmatic attacks (not really anymore because of beta -2 specific agonists)
- Prolonged action of local anesthetics (alpha)
- Topical hemostatic agent (alpha)
- Cardiac arrest ( alpha – increase diastolic pressure)
Adverse effects of Epinephrine
** DO NOT USE ON HYPERTHYROID PATIENTS because increase in thyroid hormone increases epinephrine receptors = crisis
- Marked HYPERTENSION
- Arrhythmias
- Angina
- Necrosis following extravasiation