Adrenergics Flashcards
Phenylephrine: Brand Name
Neosynephrine
Phenylephrine: Description
Synthetic alpha-receptor agonist, alpha1»alpha2
Phenylephrine: Actions
Produce vasoconstriction and venoconstriction by stimulating contraction of vascular smooth muscle cells
Phenylephrine: Indications (3)
Nasal decongestant
Mydriatic (dilate pupil for eye exam)
Increase BP in vasodilated state
Phenylephrine: Other facts (3)
Less potent vasoconstrictor than NE
Not inactivated by COMT
Topical (eye, nose), IV (increase BP)
Clonidine: Brand name
Catapres
Clonidine: Description
Synthetic and selective alpha-2 receptor agonist
Clonidine: Actions
Stimulate alpha-2 receptors in brainstem -> down-regulation of SNS
Clonidine: Indications (2)
Treat HTN
Treat/prevent migraine
Clonidine: Other Facts (3)
May be given orally or patch
Causes sedation and dry mouth
If given IV or OD can cause increased BP
Isoproterenol: Brand Name
Isuprel
Isoproterenol: Description
Synthetic beta-1 and beta-2 receptor agonist
Isoproterenol: Action
Potent agonist at both beta receptors
Isoproterenol: Indications (3)
Increase cardiac contractility
Increase HR
Increase cardiac conduction
Isoproterenol: Other facts (3)
Given intravenously
No longer used as much in CCU
Also causes vasodilatation, tachyarrhythmias
Dobutamine: Brand name
Dobutrex
Dobutamine: Description
Synthetic beta-1 receptor agonist, with very little alpha stimulation at high doses
Dobutamine: Actions
Potent agonist at beta-1 receptors in heart (increase contractility) and blood vessels (dilates renal and mesenteric vessels
Dobutamine: Indications (2)
Increases cardiac contractility more than HR
Useful in CCU for pts in cardiogenic shock, where you do not want to produce tachycardia (eg post MI)
Dobutamine: Other facts (2)
Given as IV infusion
Side effects: unwanted tachycardia, HTN, ectopy
Albuterol: Brand name
Ventolin
Albuterol: Description
Synthetic selective beta-2 (»beta-1, esp at low doses) receptor agonist
Albuterol: Action
Potent agonist at beta-2 receptors on smooth muscle cells in airways
Albuterol: Indications (2)
Prompt-acting rescue inhaler for asthma, COPD (bronchodilator)
Inhibit premature labor (relaxes smooth muscle cells in uterus)
Albuterol: Other facts (4)
Most often given as MDI
Can be given via nebulizer
Rarely given as IV infusion
Side effects: anxiety, tachycardia, tremor
Mirabegron: Brand name
Myrbetriq
Mirabegron: Description
Synthetic selective beta-3 receptor agonist (»beta-1 and -2)
Mirabegron: Actions (2)
Stimulation of beta-3 receptors in smooth muscle of bladder
Reduces detrusor muscle tone
Mirabegron: Indications (3)
Treatment of pts with overactive bladder with features of urinary urgency or frequency
Increases bladder capacity
No anticholinergic symptoms
Mirabegron: Other facts (2)
Approved by FDA in June 2012
Administered orally as extended release tablets
Dopamine: Description
Endogenous/synthetic agonist at DA, beta-1, and alpha-1 receptors
Dopamine: Actions (3)
Relative potency depends somewhat on dose being delivered
DA agonist = low dose
Beta-1 agonist = medium dose
Alpha-1 agonist = high dose
Dopamine: Indications (2)
Shock of various etiologies in ICU
Can -> increased contractility (b1), vasoconstriction (a1), and improved mesenteric and renal perfusion (DA)
Dopamine: Other facts
Given IV, preferably for short duration
Ephedrine: Description
Alkaloid obtained from plant
Ephedrine: Actions (2)
Acts indirectly to release NE from adrenergic nerve endings
Also some direct agonism at receptors
Ephedrine: Indications (2)
Mild to moderate hypotension during surgery
Nasal congestion
Ephedrine: Other facts (4)
Prolonged duration of action
Potent CNS stimulant
Side effects: HTN, insomnia
Banned OTC
Pseudoephedrine: Brand name
Sudafed
Pseudoephedrine: Description
Synthetic derivative of ephedrine
Pseudoephedrine: Actions (2)
Acts indirectly to release NE from adrenergic nerve endings
Some direct agonism at alpha and beta receptors
Pseudoephedrine: Indications (2)
Nasal and sinus decongestant
Less ability to dilate bronchioles than ephedrine
Pseudoephedrine: Other facts (3)
Need to report bulk sales
Locked behind counter, need ID to purchase
Risk of death for kids <2
Amphetamine: Description
Synthetic compound similar to ephedrine
Amphetamine: Actions
Acts indirectly to release NE from adrenergic nerve endings
Amphetamine: Indications (3)
Obesity
Narcolepsy
ADHD
(none FDA approved)
Amphetamine: Other facts (2)
V. high risk of dependence
Insomnia, restlessness, tremor
Tyramine: Description (2)
Naturally occurring byproduct of tyrosine metabolism
Present in many aged or fermented foods - red wine, smelly cheeses, pickled herring
Tyramine: Actions
Acts indirectly to release NE from adrenergic nerve endings
Tyramine: Indications (3)
Obesity
Narcolepsy
ADHD
(none FDA approved)
Tyramine: Other facts (3)
Metabolized in liver by MAO
Caution in pts on MAOIs
Chance of food/drug interaction
Cocaine: Description
Naturally occurring but purified alkaloid extracted from coca plant
Cocaine: Actions (3)
Acts indirectly to block reuptake of NE (also epi, DA) at synapse
Can stimulate release of NE, epi, and DA from neuron
Also acts as local anesthetic and CNS stimulant
Cocaine: Indications (2)
Nose bleeds (anesthesia + vasoconstriction) Anesthesia for corneal surgery
Cocaine: Other facts (4)
CNS stimulation more intense, shorter lasting than amphetamine
Can be smoked, snorted, or injected
Side effects: HTN, tachycardia, arrhythmias, seizures, MI
Controlled substance
Prazosin: Brand name
Minipress
Prazosin: Drug class (3)
Pharmacologic: selective alpha-1 adrenoceptor blocker
Therapeutic: antihypertensive, treatment of BPH (not as good as tamsulosin)
Prazosin: Pharmacodynamics (1)
Blocks alpha-1 receptors on arterioles and veins -> inhibits NE-mediated vasoconstriction and venoconstriction
Prazosin: Pharmacokinetics (4)
Available po or transdermal
Variable oral bioavailability (60%)
Onset 2h, duration 12-24h
Extensively metabolized in liver
Prazosin: Toxicity
Excessive hypotension with passing out, esp. orthostatic and in pts on diuretics (this is why it’s not first line therapy)
Prazosin: Interactions
Additive effects with most other antiHTVs, esp. diuretics
Prazosin: Special considerations (2)
Start gradually, at bedtime, to avoid first-time passing out
Male pts with BPH?
Prazosin: Indications/dose/route
Monotherapy: 1mg tid -> 20mg divided tid
Prazosin: Monitor (3)
BP, weight, edema
Tamsulosin: Brand name
Flomax
Tamsulosin: Drug class (2)
Pharmacologic: selective alpha-1 adrenoceptor blocker
Therapeutic: treatment of obstructive symptoms of BPH
Tamsulosin: Pharmacodynamics
Selectively blocks alpha-1 receptors, but preferentially in the prostate -> relaxation of smooth muscles in bladder neck and prostate -> improved urine flow, reduced symptoms
Tamsulosin: Pharmacokinetics (3)
Completely absorbed after oral ingestion
>90% metabolized by CYP450 enzymes
Half life about 6 hours, duration of action up to 15 hrs (slow absorption)
Tamsulosin: Toxicity (3)
Excessive hypotension with syncope, esp. orthostatic and in pts on diuretics
Allergic reactions
Decreased libido
Tamsulosin: Interactions
Additive effects with most other antihypertensives, esp. diuretics
Tamsulosin: Special considerations (3)
Rule out carcinoma of prostate before beginning treatment
Do not crush or chew (will speed absorption)
Can also be used to treat spasm of ureter in pts with kidney stones
Tamsulosin: Indications/dose/route
For symptoms of BPH, 0.4mg po qd or bid; similar for renal colic from kidney stones
Tamsulosin: Monitor
BP
Phentolamine: Brand name
Regitine
Phentolamine: Drug class (2)
Pharmacologic: non-selective competitive alpha-adrenoceptor blocker
Therapeutic: antihypertensive drug for pts with pheochromocytoma
Phentolamine: Pharmacodynamics
Blocks ***alpha-1 and alpha-2 receptors at presynaptic and postsynaptic alpha receptors, decreasing preload and afterload
Phentolamine: Pharmacokinetics (2)
**Only via IV (F=100%)
Plasma half life ~20min
Phentolamine: Toxicity (3)
Excessive hypotension with syncope, esp. orthostatic and in pts on diuretics
Allergic reactions
Decreased libido
Phentolamine: Interactions
Additive effects with most other antihypertensives, esp. diuretics
Phentolamine: Special considerations (2)
Rule out carcinoma of prostate before beginning treatment
Can also be used to treat spasm of ureter in pts with kidney stones
Phentolamine: Indications/dose/route (5)
Aid in Dx of pheo
***Treatment of intra-op HTN during pheo removal surgery
Prevention of dermal sloughing after extravasation of NE infusion
**Hypertensive crisis from sympathomimetic amines (tyramine - MAOI interaction) or overdose of cocaine
Phentolamine: Monitor
BP
Atenolol: Brand name, others in class
Tenormin Metoprolol (Toprol XL) - has most studies done
Atenolol: Drug class (5)
Pharmacologic: specific beta-1 blocker
Therapeutic: antihypertensive, anti-arrhythmic, primary and secondary prevention of MI, antianginal
Atenolol: Pharmacodynamics (2)
Binds directly to beta-1 receptors (beta-1»beta-2) -> lower BP via decreased CO and decreased RAAS activation
Less effective in preventing strokes than other drugs
Atenolol: Pharmacokinetics (5)
Available PO or iv Variable oral F Onset 1-2h, duration 12-24h Can be given once per day Renally excreted (longer half life) Metoprolol has hepatic metabolism (shorter half life)
Atenolol: Toxicity (4)
Excessive hypotension
Bradycardia
Heart block can worsen severe CHF (but indicated for mild to moderate CHF)
***Worsen bronchospasm in severe asthmatics
Atenolol: Interactions (2)
Additive effects with most other antihypertensives
Additive AV block with CEBs
Atenolol: Special considerations (4)
May be especially useful in HTN pts with exertional angina, MI, a fib
Watch out for abrupt withdrawal
No longer first line drug for essential HTN
Metoprolol needs to be taken several times per day
Atenolol: Indications/dose/route
For treatment of hypertension, 25-100mg/day in one or two doses
Atenolol: Monitor (3)
BP, HR, exercise tolerance
Propranolol: Brand name
Inderal
Propranolol: Drug class (5)
Pharmacologic: **non-specific beta-receptor blocker
Therapeutic: antihypertensive, antiarrhythmic, primary and secondary prevention of MI, anti-anginal
Propranolol: Pharmacodynamics (2)
Binds directly to beta-1 and beta-2 receptors -> lower BP via decreased CO and decreased RAAS activation
Less effective in preventing strokes than other drugs
Propranolol: Pharmacokinetics (4)
Available po or IV
Variable oral F
Onset 1-2h, duration 12-24h
Can be given once per day
Propranolol: Toxicity (4)
Excessive hypotension
Bradycardia
Heart block can worsen severe CHF (but indicated for mild to moderate CHF)
***Worsen bronchospasm in severe asthmatics
Propranolol: Interactions (2)
Additive effects with most other antihypertensives
Additive AV block with CEBs
Propranolol: Special considerations (3)
May be especially useful in HTN pts with exertional angina, MI, a fib
Watch out for abrupt withdrawal
No longer first line drug for essential HTN
Propranolol: Indications/dose/route
For treatment of hypertension, 25-100mg/day in one or two doses
Propranolol: Monitor (3)
BP, HR, exercise tolerance
Labetalol: Brand name, others in class
Trandate
Carvedilol/Coreg (know)
Labetalol: Drug class (3)
Pharmacologic: mixed alpha and beta-receptor blocker
Therapeutic: antihypertensive, treatment of CHF (coreg)
Labetalol: Pharmacodynamics (2)
Reduces BP by blocking access of NE to beta- and alpha-1 receptors
Pts differ in degree of beta-blockade vs alpha blockade
Labetalol: Pharmacokinetics (3)
Excellent absorption but high first-pass effects -> F~25%
Onset 1-2h po, 2-5 min iv
Extensively metabolized in liver by IID6
Labetalol: Toxicity (3)
Avoid in pt with bradycardia, heart block, CHF, asthma, shock Use with caution in pts with cardiomyopathy, pheo Pregnancy class D
Labetalol: Interactions
Additive effects with most other antihypertensives
Labetalol: Special considerations (3)
Use reduced doses in pts with impaired liver function
Dizziness most troubling early side effect
Most often used for hypertensive crises
Labetalol: Indications/dose/route
Most commonly given iv with initial small boluses of 20mg, followed by continuous infusion at 2mg/min
Not usually given po for chronic treatment
Labetalol: Monitor (2)
BP, HR
