Endogenous & Synthetic Catecholamines Flashcards
Epinephrine: Class
Endogenous Catecholamine
Adrenergic Agonist
Epinephrine: Use
Cardiac Arrest
Hypotension
Allergic Reaction
mixed with Local Anesthetics
Epinephrine: Mechanism of Action
Agonist of Beta 1, Beta 2, Alpha 1 and Alpha 2 receptors
-> Increases cAMP -> Increasing Calcium
Increases BP, CO, Bronchial relaxation, stabilizes mast cells
Epinephrine: Dose
Cardiac Arrest: 1 mg
Anaphylaxis: 100-500 mcg
Infusion: 2-20 mcg/min
LA Mix: 1 : 200,000 (5mcg/mL)
Epinephrine: Pharmacokinetics
Absorption: IV, IM, Inhalation
Onset: 1 minute
Duration of Action: 5 minutes
Metabolism: MAO, COMT
Elimination: Renal
Epinephrine: Contraindications
AVOID in peripheral nerve blocks
Caution in:
CAD
Hyperthyroidism
Pheochromocytoma
Epinephrine: Considerations
Tachycardia
Arrythmias
Angina
HTN
Decrease perfusion to splanchnic organs/uterus
gangrene in digits
Norepinephrine: Class
Endogenous Catecholamine
Adrenergic agonist
Norepinephrine: Use
Treatment of Hypotension
Norepinephrine: Mechanism of Action
Agonist of Alpha 1, Alpha 2, and weakly Beta 1 receptors
-> Increases cAMP -> Increases Calcium
Results in increased BP
Norepinephrine: Dose
1-20 mcg/min
Norepinephrine: Pharmacokinetics
Absorption: IV
Onset: 1 minute
Duration of Action: 2 minutes
Metabolism: MAO, COMT
Elimination: Renally
Norepinephrine: Contraindications
Avoid in Peripheral nerve blocks
Caution with:
Hyperthyroidism
Pheochromocytoma
Norepinephrine: Considerations
May cause Bradycardia (Baroreceptor reflex)
HTN
Profound decrease in perfusion to splanchnic organs and uterus
Prefer Central access d/t extravasation
Ephedrine: Class
Synthetic Catecholamine
Ephedrine: Use
Treatment of Hypotension WITH bradycardia
With GA/Spinal blockade to treat hypotension/bradycardia
Ephedrine: Mechanism of Action
Stimulates both Alpha and Beta Receptors directly
Indirectly causes release of endogenous catecholamines
Both Central and peripheral actions
Ephedrine: Dose
5 mg Bolus
Ephedrine: Pharmacokinetics
Absorption: IV, IM
Onset: 1 minute
Duration of Action: 10-60 minutes
Metabolism: into Norephedrine
Elimination: Renal
Ephedrine: Contraindications
Patient taking MAOIs, TCAs, COCAINE
Ephedrine: Considerations
Long 1/2 life
Subsequent doses need to be increased
Caution with:
CAD
Tachycardia
HTN
Phenylephrine: Class
Alpha 1 adrenergic agonist
Phenylephrine: Use
Treatment of Hypotension
Phenylephrine: Mechanism of Action
Agonist of Alpha1 receptor
-> cAMP -> Calcium levels
Results in constriction of smooth muscle around vasculature = Increased BP
Phenylephrine: Dose
Infusion + Bolus
Small Boluses: 40 - 80 mcg
Infusion: 20 - 50 mcg/min
Phenylephrine: Pharmacokinetics
Absorption: IV, Intranasal, Occular
Onset: 1 minute
Duration of Action: 15 minutes
Metabolism: MAO
Elimination: Renal
Phenylephrine: Contraindications
Caution in patients with BRADYcardia
Hyperthyroidism
Pheochromocytoma
Phenylephrine: Considerations
Can cause reflex bradycardia from vagus nerve leading to reduced cardiac output
Best for Hypotension with Normal HR
Can be given to prevent nose bleeds
Dobutamine: Class
Synthetic Catecholamine, selective Beta1 adrenergic agonist
Dobutamine: Use
Chemical Stress Test
Increase Cardiac Output (In sepsis, cardiogenic shock)
Dobutamine: Mechanism of Action
Acts on Beta1 to increase cAMP causing Increase in Calcium levels
= Increase in Contractility and Cardiac Output
Dobutamine: Dose
2 - 20 mcg/kg/min
Dobutamine: Pharmacokinetics
Absorption: IV
Onset: 1 minute
Duration of Action: 10 minutes
Metabolism: MAO, COMT
Elimination: Renal
Dobutamine: Contraindications
Tachycardia
CAD
Hypertrophic Cardiomyopathy
Dobutamine: Considerations
Increases HR
Decreases SVR
Inhibits PLTs
Dopamine: Class
Endogenous nonselective adrenergic and dopaminergic agonist
Dopamine: Use
Increase BP and HR
Dopamine: Mechanism of Action
Stimulates Dopamine receptors, Beta and Alpha receptors in a dose dependent manner
Dopamine: Dose
Dopamine receptors: 2 mcg/kg/min
Beta receptors: 2 - 5 mcg/kg/min
Alpha receptors: >10 mcg/kg/min
Dopamine: Pharmacokinetics
Absorption: IV
Onset: 2 minutes
Duration of Action: 10 minutes
Metabolism: MAO and COMT
25% metabolism into Norepinephrine
Excretion: Renal
Dopamine: Contraindications
Hypernatremia
Pt taking MAOI, TCAs
Tachycardia/arrythmias
Dopamine: Considerations
Active metabolite: Norepinephrine
Increases urine output and Na levels
Risk for extravasation
Vasopressin: Class
Exogenous antidiuretic peptide & vasopressor
Vasopressin: Use
Septic Shock
ACE inhibitor related hypotension
Vasopressin: Mechanism of Action
Stimulates V1 receptors on vascular smooth muscle, glomerular mesangial cells and vasa recta
ADH (activates V2 receptors)
Vasopressin: Dose
Infusion +Bolus
Bolus: 1 unit
Infusion: 0.01- 0.08 units/min
Vasopressin: Pharmacokinetics
Absorption: IV
Onset: 1 minute
Duration of Action: 10 minutes
Metabolism: Tissue peptidase
Elimination: Renal
Vasopressin: Contraindications
Hypersensitivity
Vasopressin: Considerations
Gastrointestinal ischemia
Decreased Cardiac Output
Skin/Digit necrosis
Cardiac Arrest
Milrinone: Class
Phosphodiesterase 3 Inhibitor
Milrinone: Use
Cardiogenic shock
Right sided Heart Failure
Inotropy in the setting of Beta Blockade
Milrinone: Mechanism of Action
Inhibits PDE
(usually breaks down cAMP and cGMP)
More cAMP and cGMP in myocardium and smooth muscle
Myocardium: More cAMP -> Increase in Calcium levels = Increased Contractility
Smooth Muscle: More cGMP causes vasodilation = lowering PVR
Milrinone: Dose
Loading Dose: 50 mcg/kg over 10 minutes
Infusion: 0.375- 0.75 mcg/kg/min
Milrinone: Pharmacokinetics
Absorption: IV
Onset: 5 minutes
Duration of Action: 6 hours
Metabolism: Hepatic
Elimination: Renal
Milrinone: Contraindications
Hypotension
Renal Failure
Milrinone: Considerations
Arrythmias
Albuterol: Class
Selective Beta2 Agonist
Albuterol: Use
Bronchodilation
Albuterol: Mechanism of Action
Acts directly on Beta 2 receptors
activates adenylyl cyclase which increases cAMP and decreases Calcium causing smooth muscle relaxation and bronchodilation
Albuterol: Dose
90 mcg / puff
Albuterol: Pharmacokinetics
Absorption: Inhalation
Onset: 5 minutes
Duration of Action: 4 hours
Metabolism: MAO
Elimination: Renal
Albuterol: Contraindications
Allergy
Albuterol: Considerations
Tremors
Tachycardia
Hypokalemia