Sympathetic Drugs (Adrenergic) Flashcards
Neurotransmitter in Sympathetic
Preganglionic - Ach
Postganglionic - NE
Catecholamines Synthesis
Phenylalanine → L-tyrosine → L-Dopa → Dopamine → Norepinephrine → Epinephrine
Enzymes:
Phenylalanine hydroxylase
Tyrosine Hydroxylase
Dopa decarbocylase
Dopamine b-hydroxylase
Phenylethanolamine N-Methyltransferase
Neurotransmitter Synthesis
Tyrosine Uptake → DOPA → Dopamine → NE Synthesis → NE release → NE Binding → Metabolism (MAO, COMT), → Reuptake
Metyrosine
Inhibits Tyrosine Hydroxylase
Reserpine
Inh. reuptake of NE to vesicles
Bretylium
Inh. release of NE
TCA, Cocaine
Inh. reuptake of NE, Binds to NET
Non-Selective Direct-Acting
Epinephrine
Norepinephrine
Dopamine
Natural Catecholamines Pharmacodynamics
Higher affinity to Beta than alpha
Epinephrine: B1 = B2 > A1
Norepinephrine: B1 > A1
Dopamine: D1 > B1 > A1
Natural Catecholamines Pharmacokinetics
Undergo extensive first pass effect
(decreased oral BA)
- Routes: IV, SQ, inhalation
- Metabolism by MAO & COMT
DOC for Anaphylactic Shock & Cardiac stimulant
Epinephrine
Treating patients with bleeding conditions and ventricular fibrillation
Epinephrine
DOC for Septic Shock
Norepinephrine/Noradrenaline/Levaterenol - Inotropic Agent
Treatment of shock with Hypertension (Cardiogenic Shock, Septic Shock, Hypovolemic Shock)
Dopamine
Dopamine Doses
1-3 mcg/kg/min: D1 activation
2-5 mcg/kg/min: B1 activation
> 5 mcg/kg/min: A1 activation
Alpha1 Overstimulation
Digital necrosis
Beta 1 Overstimulation
Tachyarrhythmias
Non-selective Beta Agonist
Isoproterenol
B1 = B2 > A
Beta 1 Selective Agonist
Dobutamine
Dobutamine
Cardioselective
Shock with NO Hypertension
First line for Cardiogenic Shock & Acute Heart Failure
Dobutamine
Beta 2-selective Agonist
SABA (short-acting beta agonists)
* Albuterol/Salbutamol
* Terbutaline
LABA (long-acting)
* Salmeterol - slow onset of action
* Formoterol - fast onset of action
* Bambuterol
* Indacaterol
Tocolytics
* Ritodrine
* Isoxsuprine - most common
* Terbutaline (SQ) - off-label
Alpha1-selective Agonists
Phenylephrine (decongestant)
Methoxamine
Propyhexedrine
Tetrahydrozoline
Oxymetazoline
Nafazoline
Alpha 2-selective Agonists
Clonidine
Methyldopa
Guanfacine
Guanabenz
Dexmedetomidine
Aparaclonidine
Brimonidine
Management of Hypertension in pregnant
Methyldopa
Alpha-2 agonist, false neurotransmitter
Methyldopa
Converted to alpha-methylnorepinephrine
(Coomb’s Test – test for hemolytic anemia)
Phenylephrine
Nasal decongestant
Orthostatic hypotension
Mydriasis
Treatment of orthostatic hypotension caused by infections in infants or induced by psychotropic agents
Midodrine - Alpha 1 agonist
Topical decongestant
Oxymetazoline
Activates ocular alpha-2; Antiglaucoma
Apraclonidine, Brimonidine
Clonidine uses
Treatment of ADHD
Anti-hypertension
Treatment of opioid Dependence
Dexmedetomidine
Analgesic + Sedative effect
D1-selective Agonist
Fenoldepam - Hypertension crisis
Mirabegron
Selective β3 agonist
Relaxes detrusor smooth muscle, increases urinary bladder capacity, promotes urinary retention
Mirabegron
Indirect-Acting
a. NE Displacers
* Amphetamine, Methylphenidate, Modafinil
b. Reuptake Inhibitors
* TCAs, Cocaine, SNRIs, Reboxetine
Treatment of narcolepsy
Amphetamines
DOC for ADHD
Methylphenidate
Psychostimulant
Modafinil
First natural local anesthetic
Cocaine
Ephedrine
Obtained from Ma Huang
Nasal decongestant
Anti-asthma
Management of Hypotension
Pseudoephedrine
Nasal decongestant
Phenylpropanolamine/Norephedrine
Nasal decongestant
Risk of cerebral hemorrhage