Adrenergic Flashcards
\_\_\_\_\_\_ nervous system -Regulates all organ systems and blood pressure Organ systems, blood pressure Hormone vs. neurotransmitter Adrenal medulla
Sympathetic nervous system
Does NE get broken down right away?
No; ACh does
What enzyme reuptakes NE in pre-synaptic scenarios?
Monoamine oxidase
What enzyme reuptakes NE in postC-synaptic scenarios?
Catechol-O-Methyltransferase
____ sympathetic agonists:
Route
Affinity
Expression of receptor subtypes
Direct
____ sympathetic agonists:
Catecholamine displacement
Amphetamines
Decreased NE clearance
Reuptake inhibition
Indirect
\_\_\_\_ receptors: α1 α2 β1 β2 Dopamine Sympathomimetic vs sympatholytic
Adrenergic receptors
\_\_\_\_\_\_ receptors Can be downregulated / desensitized Congestive Heart Failure (CHF) Acidosis Hypoxia
Adrenergic receptors
Vasoconstriction Blood pressure increased Mydriasis Urinary sphincter constriction Peripheral vascular beds Excitatory
Alpha 1
In the vasculature Inhibition of NE and ACh Decreased sympathetic tone Decreased BP Sedation Inhibitory
Alpha-2
Cardiac excitation Increased rate, contractility, conduction -Excitatory -Heart
Beta-1
Are beta and alpha 1s excitatory or inhibitory?
Excitatory
Are beta and alpha 2s excitatory or inhibitory?
Inhibitory
Bronchodilation Smooth muscle relaxation Skeletal muscle vasodilation Decreased vascular resistance -Inhibitory
B2
Resistance vessel vasodilation Renal Splanchnic Coronary Cerebral
Dopamine
What are the endogenous catechloamines?
epi
NE
dopamine
Where does dopamine get released from?
Brain and kidney
Where does NE get released from?
Sympathetic nerve endings
Where does epi get released from?
adrenal medulla
Endogenous Primary neurotransmitter at sympathetic nerve endings Maintenance of sympathetic tone BP No cardiac output changes Minimal chronotropic changes Increased coronary blood flow Caution with prolonged infusions Uses: - increase bp in super sick pts
NE
Endogenous Only released by adrenal medulla Stress preparation coronary blood flow Caution prolonged infusions Uses: -B2 action in low dose for anaphylaxis -Vasoconstriction in nerve block
Epi
Endogenous NE precursor Dose-specific effects Low dose (0.5 – 3 mcg/kg/min) Intermediate (3 – 10 mcg/kg/min) High (10 – 20 mcg/kg/min) Uses: -Increases bp and significantly increases HR -Increase risk of ventricular arrthmias
Dopamine
Synthetic
Augments myocardial contractility
Dose-dependent increase in stroke volume (SV) and cardiac output (CO)
Alpha agonist AND antagonist
Beta-mediated vasodilation (low dose)
High dose increases myocardial O2 consumption
Uses:
-cardiac stress test
-INcrease contraction with smooth muscle dilation (HF pts)
Dobutamine
Synthetic All alpha, no beta Not a catechol derivative, not metabolized by COMT Can lead to baroreceptor-mediated decrease in HR Push dose pressor Uses: -increases bp -Only taken up in pre-synaptic neuron by MOT
Phenylephrine
Phosphodiesterase-3 inhibitor Inhibits breakdown of cAMP Positive inotropy Potent vasodilator Increased diastolic relaxation Reduced preload and afterload Good in the setting of receptor downregulation Uses: - increase force of contraction -MOre likely to elicit B2 effect than dobutamine -More likely to cause hypotension
Milirone
AKA: antidiuretic hormone
Stored in posterior pituitary
Released when plasma osmolality increases or BP drops
V1 and V2 receptor agonist
Neutral to negative impact on CO
Dose dependent SVR and vagal tone increase
Not affected by pH
Uses:
- Decreases urination to get osmolarity of blood back to normal
Vasopressin
What is the drug of choice for pregnant women to increase bp?
Methyldopa
Drop BP by reducing
sympathetic tone
Effective antihypertensive
Class effect = sedation
Alpha 2 selective agonists
Rapid CNS uptake
Stimulant
Effects mediated by NE and DA
Amphetamine
Amphetamine variant Similar effect and abuse potential Use: ADD-spectrum Caution - UDS
Methylphenidate (Ritalin)
Psychostimulant Totally different from amphetamine NE, DA reuptake inhibition NE, DA, 5-HT3, glutamate increase; GABA decrease Use: narcolepsy
Modafinil (Provigil)
Selective NE reuptake inhibition No CV effects Clonidine-like effect Use: ADD
Straterra
Local anesthetic, peripheral sympathomimetic Reuptake inhibition, especially dopamine Excited delirium Avoid concurrent beta- blockade Use: epistaxis
Cocaine
\_\_\_\_\_ agonism Key to management of acute asthma Common “allergy” in dentistry7.9% Triggered by allergens, stress, food, drugs Angioedema = similar but different
Beta 2 agonism
The following drugs are ______:
Albuterol
Levalbuterol
Terbutaline
Short term control
Short acting beta agonists
(SABA)
The following are \_\_\_\_: Formoterol Salmeterol Blocks receptors 12-18h NOT FOR ACUTE ATTACKS Have to be used with steroids Advair = salmeterol + fluticasone Symbicort = formoterol + budesonide Dulera – formoterol + mometasone
Longer term control
Long acting beta agonists (LABA)
For \_\_\_\_ pts: Minimize likelihood of exacerbation Talk to your patient to learn their management strategies Instruct pt. to bring albuterol inhaler to all appointments Decrease stressors
Asthma pts
For \_\_\_\_ pts: Drug considerations No ASA or NSAIDS Avoid histaminic drugs Avoid antihistamines Avoid cholinergics In an emergency Supplemental O2 Consider epinephrine 0.3 mg IM (or use EpiPen)
Asthma pts
What drugs should be avoided for asthma pts?
No ASA or NSAIDS
Avoid histaminic drugs
Avoid antihistamines
Avoid cholinergics
______ alpha antagonists
Concentration dependent
Duration dependent on t1/2
reversible
______ alpha antagonists
Body has to generate new receptors
Drug effect can persist even after drug is cleared
-Phenoxybenzamine
Irreversible
\_\_\_\_\_ drugs pharm effects Cardiovascular α1 blockade blocks vasoconstriction Orthostatic hypotension Other Miosis, nasal stuffiness Decreased resistance to urinary flow
Alpha blockers
____ is the most common issue with alpha blockers
-vasoconstriction is inhibited
Orthostatic hypotension
Blocks α1 and α2 Decreased PVR and cardiac stimulation Can lead to CV adverse reactions - Uses: treats extravasated drugs
Phentolamine
What 3 drugs? Selective α1 Arterial and venous vascular smooth muscle relaxation and prostate relaxation 50% bioavailabilityFirst pass effect Uses: BPH
Prazosin
Terazosin
Doxazosin
Competitive α1 blocker High bioavailability More specific to prostate Less orthostatic hypotension
Tamsulosin
Antagonize effects of catecholamines and beta agonists
Differ in affinity for β1 and β2
β1 specificity decreases as dose increases
End in -lol
Beta blockers
What are the 6 B1 specific beta blockers?
Betaxolol Esmolol Acebutolol Metoprolol Atenolol Nebivolol
Beta-1 selective Short t1/2 Quick onset Requires central line for administration Great for tight BP control
Esmolol
Beta and alpha blockade 3:1 oral 7:1 IV Dose dependent duration of action up to 20 hours - minimum effect on alpha -for cocaine users, dont use beta blockers
Labetalol
T/F: for cocaine users, don’t use beta blockers
True
____ specific drugs are safer for asthmatic pts?
B1
Should you use non-specific B-blockers and epi on asthmatic pts?
No