(6) Autonomic Nervous System Drugs II (Norepinephrine & Epinephrine) Flashcards
Epinephrine (Class, Receptor Affinity, Dose-Dependent Effects, Uses, Adverse effects)
- Class: Non-selective, direct adrenergic agonist
- Receptor Affinity: Alpha 1 = Alpha 2; Beta 1 = Beta 2;
- Dose-Dep Effects:
- Low dose = Beta effects; - High dose = Alpha 1 effects - Uses: Anaphylactic shock, cardiac arrest, topical vasoconstriction
- Adverse effects: tremor, palpitations, headache & arrhythmias
Norepinephrine (Class, Receptor Affinity, Uses, Adverse effects)
- Class: Non-selective direct adrenergic agonist
- Receptor Affinity: Alpha 1 = Alpha 2; Beta 1 »_space; Beta 2
- Uses: Hypotension
- Adverse effects: tremor, palpitations, headache & arrhythmias
- Greater peripheral vascular resistive effects than epinephrine (b/c less Beta 2 binding, which causes vasodilation)
Isoproterenol (Class, Receptor Affinity, Uses, Adverse effects)
- Class: Non-selective direct adrenergic BETA agonist
- Receptor Affinity: Beta 1 = Beta 2
- Uses: potent vasodilator (Beta 2 effects), inotropic agent (increase force of contraction) (Beta 1 effects)
- Adverse effects: tachycardia & arrhythmias
Dobutamine (Class, Receptor Affinity, Uses, Adverse effects)
- Class: Selective Beta-1 Agonist
- Receptor Affinity: Beta 1 > Beta 2»_space;» Alpha
- Uses: Acute heart failure, (potent inotropic agent) & Cardiac stress testing
- Adverse: HTN & tachycardia
Albuterol, Levalbuterol & Salmeterol (Class, Effects, Uses)
- Class: Selective Beta 2 Agonist
- Effects: Bronchodilation
- Uses: Asthma & COPD
Terbutaline (Class, Route of Administration: Effects & Uses)
- Class: Selective Beta 2 Agonist
- ROA: Effects & Uses:
- PO = Bronchodilation; Asthma
- IV = Uterus smooth muscle relaxation; Delay premature labor
Phenylephrine (Class, Route of Administration: Effects & Uses)
- Class: Selective Alpha 1 Agonist
- ROA: Effects & uses
- IV: Vasoconstriction; Hypotension & Shock
- PO: OTC decongestant
Oxymetazoline (Class, Uses & Adverse Effects)
“Afrin” Nasal Spray
- Class: Selective Alpha 1 Agonist
- Uses: Topical nasal decongestant
- Adverse effects: Rebound congestion (Tachyphylaxis) if used more than several days
Clonidine (Class, Uses & ROA)
- Class: Selective Alpha 2 Agonist
- Uses: Centrally acting anti-HTN agent & Attenuating substance withdrawal symptoms
- PO or Transdermal patch
Alpha-Methyldopa (Class & Uses)
- Class: Selective Alpha 2 Agonist
- Uses: Centrally acting anti-HTN agent
- Useful during pregnancy
Amphetamine & Methamphetamine (Class, Mechanism, Effects & Chemical Characteristics)
- Class: Indirect Adrenergic Agonist
- Mechanism: Stimulate presynaptic NE & Dopamine release
- Effects:
- Stimulatory on mood/alertness
- Apetite depressant
- Peripheral vasoconstriction
- Cardiac stimulant - Chemical Characteristics: Lipid soluble, thus enters CNS
Methylphenidate (Class, Mechanism, Effects & Chemical Characteristics)
“Ritalin”: Amphetamine derivative w/ similar action
- Class: Indirect Adrenergic Agonist
- Mechanism: Stimulate presynaptic NE & Dopamine release
- Effects:
- Stimulatory on mood/alertness
- Apetite depressant
- Peripheral vasoconstriction
- Cardiac stimulant - Chemical Characteristics: Lipid soluble, thus enters CNS
Cocaine (Class, Mechanism & Effects)
Similar to Amphetamine: shorter/more intense
- Class Indirect Adrenergic Agonist
- Mechanism: Blocks NET & DAT reuptake of NE, Dopamine & Serotonin
- Effects:
- Peripheral vasoconstriction
- Cardiac stimulant
- Local anesthetic (ocular surgery)
Tyramine (Class, Mechanism & Adverse effects)
Naturally occurring amine found in fermented products (cheese, sausage, red wine, beer, bananas, avocados, canned meats, sardines & yeast supplements)
- Class: Indirect Adrenergic Agonist
- Mechanism: Increases NE release
- Adverse effects: can cause HTN crisis w/ MAO inhibitors (used for depression)
Dopamine (Class, Receptor Affinity, Dose-Dependent Effects, Uses & Adverse Effects)
- Class: Mixed Adrenergic Agonist
- Receptor Affinity: D1 = D2»_space; Beta 1»_space; Alpha 1
- Dose-Dep Effects:
- Low dose: D receptor (increase renal blood flow)
- Med dose: D + Beta 1 receptors
- High dose: D + Beta 1 + Alpha 1 receptors - Uses: Cardiogenic shock & Acute renal failure
- Adverse effects @ high doses: tremor, palpitations, headache & arrhythmias
Ephedrine (Class, Mechanism, Effects)
Natural product in Ma-Haung plant
- Class: Mixed Adrenergic Agonist
- Mechanism: Alpha & Beta receptor Agonist + NE release
- Effects: Similar to Epinephrine @ high doses
Psuedoephedrine (Class, Mechanism, Uses & Adverse Effects)
“Sudafed”: Ephedrine stereoisomer
- Class: Mixed Adrenergic Agonist
- Mechanism: Alpha & Beta receptor + NE release
- Uses: Restricted OTC decongestant (primary ingredient in methamphetamine)
- Adverse Effects: Avoid in patients w/ HTN or cardiomyopathy
Phenoxybenzamine (Class, Mechanism, Receptor Affinity, Uses & Adverse Effects)
- Class: Non-Selective Alpha Blockers
- Mechanism: Non-Competitive, Irreversible Antagonist
- Receptor Affinity: Alpha 1 > Alpha 2
- Uses: Pheochromocytoma (adrenal medulla tumor = catecholamine excess)
- Adverse: Postural hypotension & Reflex tachycardia
Phentolamine (Class, Mechanism, Receptor Affinity, Uses, Adverse Effects)
- Class: Non-Selective Alpha Blockers
- Mechanism: Competitive, Reversible Antagonist
- Receptor Affinity: Alpha 1 = Alpha 2
- Uses: Pheochromocytoma & Ischemia reversal (caused by extravasation/epinephrine injection)
- Adverse Effects: Postural hypotension & Reflex tachycardia
Prazosin, Terazosin & Doxazosin (Class, Effect, Uses & Adverse Effects)
- Class: Selective Alpha 1 Blockers
- Effects: Relax vascular, bladder & prostate smooth muscle
- Uses: BPH & 3rd rate HTN-agent (increased morbidity)
- Adverse: 1st dose syncope (pt must lay down) & reflex tachycardia
Tamsulosin (Class, Effect & Uses)
“Flomax”
- Class: Selective Alpha 1 Blocker (Specific to Prostate Gland)
- Effect: Less vasodilation than other Alpha-1 blockers; little effect on BP @ normal dose
- Uses: BPH (decrease urinary obstruction)
Propranolol (Class, Receptor Affinity, Effects, Uses, Adverse Effects)
- Class: Non-selective Beta Blockers
- Receptor Affinity: Beta 1 = Beta 2
- Effects:
- Negative inotropic (cardiac contractility)
- Chronotropic (heart rate)
- Bronchoconstriction
- Decreased glycogenolysis - Uses: HTN, Arrhythmias, Angina, Migraines, Essential Tremor
- Adverse: Bradycardia, Insomnia, Heart failures, Asthma & Diabetes
Other:
- Highest lipid solubility (CNS penetration)
- Highest 1st pass effect: oral dose»_space; IV dose
Nadolol (Class, Other)
“Corgrad”
- Class: Non-Selective Beta Blockers
- Other:
- Low lipophilicity = less adverse CNS effects than propranolol
- Renal excretion
- Long T 1/2
Timolol (Class, Uses)
- Class: Non-Selective Beta Blockers
2. Uses: Topical agent for Glaucoma
Pindolol (Class, Other)
- Class: Non-Selective Beta Blocker
2. Other: Partial Beta 1 & Beta 2 Agonist (intrinsic sympathomimetic activity) = less bradycardia
Metoprolol (Class, Receptor Affinity, Uses, Other)
“Cardioselective Beta-Blocker”
- Class: Selective Beta 1 Blocker
- Receptor Affinity: Beta 1»_space; Beta 2
- Uses:
- Angina
- Low dose: Heart failure
- High dose: HTN - Other
- Safer for asthma & diabetes than non-selective beta blockers
- T 1/2 varies from 3-8 hrs depending on CYP2D6 phenotype
Atenolol (Class, Other)
- Class: Selective Beta 1 Blocker
- Other:
- Low lipophilicity = less CNS adverse effects than propranolol
- Renal excretion
- Long T 1/2
Bisoprolol (Class, Other)
“Zebeta”
- Class: Selective Beta 1 Blocker
- Other: Moderate lipophilicity
Esmolol (Class, Other)
- Class: Selective Beta 1 Blocker
2. Other: IV Only
Acebutolol (Class, Other)
- Class: Selective Beta 1 Blocker
2. Other: Partial Beta 1 agonist (intrinsic sympathomimetic activity)
Labetalol (Class, Receptor Affinity, Use, Other)
- Class: Alpha & Beta Blocker
- Receptor Affinity: Beta 1 = Beta 2; Alpha 1 > Alpha 2
- Use: Rapid BP reduction
- Other
- IV or PO
- More vasodilation than other Beta blockers due to Alpha 1 blockage
Carvedilol (Class, Receptor Affinity, Use, Other)
“Coreg”
- Class: Alpha & Beta Blocker
- Receptor Affinity: Beta 1 = Beta 2; Alpha 1 > Alpha 2
- Use: Heart failure
- Other
- IV or PO
- More vasodilation than other Beta blockers due to Alpha 1 blockage
Alpha 1 Receptor Effects (4)
- Vascular smooth muscle contraction (vasoconstriction)
- Iris dilator muscle (mydriasis = pupil dilation)
- Pilomotor smooth muscle contraction (goosebumps/hairs stand up)
- Lower urinary tract (urethra/prostate) smooth muscle contraction
Alpha 2 Receptor Effects (4)
- Platelet aggregation
- Inhibition of Adrenergic/Cholinergic neurotransmitter release (feedback inhibition)
- Inhibition of lipolysis
- Some vascular smooth muscle contraction
Beta 1 Receptor Effects (2)
Heart:
- Increase force & rate of contraction
- Increase conduction velocity
Beta 2 Receptor Effects (3)
- Respiratory, Uterine & Vascular smooth muscle RELAXATION
- Skeletal muscle potassium uptake
- Liver glycogenolysis
Beta 3 Receptor Effects (1)
Fat cells:
1. Lipolysis activation
Dopamine 1 (D1) Effects (1)
Smooth muscle:
1. Dilation of RENAL blood vessels
Dopamine 2 (D2) Effects (1)
Nerve endings:
1. Modulate NT release in CNS
Why must Catecholamines be given paraenterally?
Because they are rapidly metabolized by MAO & COMT