Pharmacology: Katzung symphathomimetics Flashcards
What are the two classes of symphathomimetics?
(1) direct acting
(2) indirect acting
What are the two classes of direct acting symphathomimetics?
(1) Alpha agonists
(2) Beta agonists
What are the two classes of indirect acting symphathomimetis?
(1) releasers
(2) re-uptake inhibitors
What are the three subclasses of direct acting sympathomimetics?
(1) catecholamines
(2) Non-catecholamines
(3) Non-catecholamine beta selective.
To what drug class do epinephrine, norepinephrine, Dopamine, isoproterenol, and dobutamine belong to?
They are catecholamines.
What is the mechanism of action for Epinephrine?
Epinephrine is an alpha 1 & 2, Beta 1,2, & 3 agonist.
What is the clinical use for epinephrine?
Epinephrine is used for anaphylaxis and hemostasis.
What are the major toxicities of epinephrine?
(1) hypertension
(2) arrythmia
(3) stroke
(4) MI
(5) pulmonary edema
What is the mechanism of action for Norepinephrine?
Alpha 1 & 2. Beta 1 agonist.
What are the clinical uses for Norepinephrine?
Neurogenic shock, last resort therapy in shock.
What are the adverse effects associated with norepinephrine?
(1) vasospasm
(2) tissue necrosis
(3) excessive blood pressure increase
(4) arrythmias
(5) infarction
What is the mechanism of action for dopamine?
D1, Alpha1, Alpha 2, beta 1, beta 2, beta 3 agonist
What are the clinical uses for dopamine?
(1) Shock
(2) renal shutdown
(3) occasionally heart failure
What are the adverse affects of dopamine?
(1) cardiovascular disturbances
(2) arrythmias
What is the mechanism of action for isoproterenol?
Isoproterenol is a Beta 1, 2, & 3 agonist
What is the clinical use for isoproterenol?
isoproterenol is used for acute asthma by nebulizer.
What is the mechanism of action for dobutamine?
Dobutamine is a beta 1 agonist
What is the primary clinical use for dobutamine?
Dobutamine is a beta 1 agonist used in acute heart failure to increase cardiac output.
What is the mechanism of action for phenylephrine?
Phenylephrine is an alpha 1 alpha 2 agonist
What is the primary clinical use for phenylephrine?
(1) decongestant
(2) Mydriatic
(3) neurogenic hyotension.
What are the adverse affects associated with phenylephrine?
(1) hypertension
(2) stroke
(3) MI
What is the mechanism of action for albuterol, metaproterenol, terbutaline, Salmeterol, and formoterol?
They are all Beta 2 agonists.
What is the primary clinical use for albuterol, metaproterenol, and terbutaline?
They are used for prompt onset for acute bronchospasm.
What are the adverse effects of the selective beta 2 agonists?
(1) tachycardia
(2) tremor.
What are clinical uses for salmeterol, and formoterol?
Salmeterol, and formoterol are not useful in acute bronchospasm. They are used only with corticosteroids for prophylaxis. Slow onset, long action.
What are the three classes of indirect acting symphathomimetics?
(1) Phenylisopropylamines
(2) cocaine
(3) Tyramine
What class of drugs do amphetamine, methamphetamine, and ephedrine belong to and what is their mechanism of action?
They are phenylisopropylamines. The MOA is that they displace stored catecholamines.
What are the clinical uses for Amphetamine and methamphetamine?
(1) narcolepsy
(2) anorexiant
(3) ADHD
What are the adverse effects associated with Amphetamine and methamphetamine?
(1) High addiction liability
(2) Paranoia
(3) aggression
(4) insomnia
(5) Hypertension
What are the clinical uses for ephedrine?
(1) narcolepsy
(2) idiopathic postural hypotension
(3) enuresis
Lower addiction liability than amphetamines
What is the mechanism of action for Cocaine?
Cocaine blocks norepinephrine and dopamine re-uptake
What are the clinical uses for cocaine?
(1) local anesthetic
(2) intrinsic hemostatic action
What are the adverse effects associated with cocaine?
(1) very high addiction liability
(2) Hypertension
(3) arrythmias
(4) siezures. (common with overdose)
What is the mechanism of action for tyramine?
Tyramine displaces stored catecholamines
What are the clinical uses for tyramine?
No clinical uses but found in fermented foods
How is tyramine metabolized?
Usually has a high first pass effect however in those taking MAO inhibitors it is absrobed.
What are the adverse effects associated with tyramine?
(1) hypertension
(2) arrythmias
(3) stroke
(4) MI
What effect can MAO and COMT inhibitors have on symphathomimetics?
They will increase the intracellular stores of catecholamines and may therefore potentiate the action of catecholamine releasers.
Amphetamines have what unique pharmacokinetic property?
amphetamines are resistant to MAO.
Where are alpha 1 receptors found?
(1) vascular smooth muscle (contraction)
(2) eye (contraction of pupillary dilator and pilomotor smooth muscle)
(3) Liver (stimulate glycogenolysis)
Where are alpha 2 receptors found?
(1) Nerve terminals (inhibits transmitters)
(2) Platelets (stimulate aggregation)
(3) Some vascular smooth muscle (contraction)
(4) fat cells (inhibits lipolysis)
(5) pancreatic beta cells (inhibits insulin release)
Where are Beta 1 receptors found?
(1) heart ( increases HR and contractility)
2) Juxtaglomerular cells (stimulates renin
Where are beta 2 receptors found?
(1) Airway, uterine, and vascular smooth muscle (relaxes)
(2) Liver (stimulates glycogenolysis)
(3) pancreatic beta cells (stimulates insulin release
(4) somatic motor neuron terminals (causes tremor)
(5) Heart (stimulates rate and force)
Where are beta 3 receptors found?
(1) fat cells (stimulates lipolysis)
Where are D1 receptors found?
renal and splanchnic blood vessels (dilates)
Where are D2 receptors found?
Nerve terminals (inhibits adenylyl cyclase.)
What kind of drug is clonidine?
Clonidine is an alpha 2 agonist
What are the effects of the alpha 2 agonists like clonidine?
(1) vasoconstriction when taken IV
(2) reduced sympathetic outflow and blood pressure when given orally.
What are the effects of beta agonists on the heart?
They increase rate and contractility. The direct effect overcomes the baroreceptor reflex from the increased pressure.
What are the effects on the heart of the pure alpha agonists?
They usually slow the heart rate because of the baroreceptor reflex.
What class of drug is tetrahydrozoline?
Tetrahydrozoline is an alpha agonist use to produce mydriasis.
What class of drugs do apraclonidine and brimonidine belong to?
They are alpha 2 agonists that are used for glaucoma
What is midrodine?
Midrodine is an alpha 1 agonist that is used for orthostatic hypertension.
