Flashcards in Dobutamine Deck (52)
What is the trade name of Dobutamine Hydrochloride?
What are the Broad Category and Sub-category drug classifications and the reason for classification for Dobutamine?
Broad Category= Sympathomimetic Drug
-derived from beta-phenylethylamine; its a synthetic analog of isoproterenol, which is made from dopamine
Sub-Category= Synthetic Catecholamine
-Dobutamine is a catecholamine because it has hydroxyl groups on the 3 and 4 carbon posns of the benzene ring of beta-phenylethylamine
What is Dobutamine a synthetic analog of?
What are the Clinical uses for Dobutamine?
-Increases CO (inotropic effect)
-Reduction in Atrial filling pressures
-Moderate increase in RBF due to increases in CO and Vasodilation
-Coronary artery vasodilation
-Decreases pulmonary artery pressures
-Increases LV stroke work index
What receptors does Dobutamine work on/ what is Dobutamine??
direct acting selective B1 adrenergic receptor agonist (but at clinical doses some Beta 2 and alpha 1 stimulation may occur)
What are the MINIMAL changes produced by Dobutamine?
-minimal effects on Systemic BP
-minimal increases in myocardial oxygen requirements
-minimal increases in HR
-minimal increases in MAP
Dobutamine produces NO change in...?
Dobutamine produces no change to minimal change in....?
peripheral vascular resistance (vasodilation)
Why is Dobutamine used for patients with organic heart disease? Patients recovering from cardiac surgery? Patients recovering from MI?
it can increase exercise tolerance and improve cardiac output in patients with CHF that present with increased HR and SVR
Why is Dobutamine used for patients with RV failure/ cor pulmonale?
Dobutamine causes Pulmonary vasodilation
What is Dobutamine used for patients with mitral valve replacement?
These patients have increased pulmonary artery pressures and Dobutamine increases CO and decreases systemic and pulmonary vascular resistance
Why is Dobutamine used in Septic Shock?
Does NOT reverse hypotension therefore; its not considered a first line drug for septic shock; after fluid resuscitation, Dobutamine can be used in conjunction with vasopressors to reverse tissue hypo-perfusion by increasing oxygen delivery and consumption though increasing CO
How is Dobutamine used to detect CAD?
Dobutamine Echocardiography: useful in patients that are unable to undergo stress testing such as patients with pacemakers, significant bradycardia or those taking high dose Beta-adrenergic blockers. Dobutamine can also be used to help determine the responsive or unresponsive areas of dyskinesia post myocardial infarction
Why is Dobutamine often used in combination therapy?
useful in the distribution of cardiac output
What are Dobutamine + low dose dopamine used in combo therapy for?
Increase Renal Perfusion
What are Dobutamine + vasodilators used in combo therapy for?
Improve CO by decreasing afterload in patients that have increased SVR
What is the MOA of Dobutamine?
-direct acting selective B1 adrenergic receptor agonist; these effects are due to the fact that the clinically available formulation of Dobutamine is a racemic mixture of enantiomers that may have differential effects on adrenergic receptor subtypes
-Dobutamine binds to beta-receptors, which are G-protein coupled receptors; these are ligand specific and once activated the G protein diffuses into the cell and through a series of reactions increases cAMP, which stimulates the production of Protein kinase C, which in turn increases the inward flux of calcium; this enhances the muscle contraction
Where are the B1 receptors located?
Cardiac Muscle (heart) (also in Kidneys)
At what dose is Dobutamine B1 selective?
What does the B2 action of Dobutamine cause?
leads to peripheral arterial vasodilation and a reduction in afterload.
What is the onset of action of Dobutamine?
1-2 minutes; 10 minutes may be required to obtain peak effect
What is the E 1/2 life of Dobutamine?
How is Dobutamine metabolized?
In tissues and the liver through the breakdown of the catechol and conjugation via MAO (monoamine oxidase) or COMT (catechol-O-methyltransferase
What and Where is MAO? COMT?
MAO- is an enzyme present in the liver, kidneys, and GI tract and catalyzes oxidative deamination
COMT- methylates the hydroxyl group on Dobutamine, which inactivates the drug and metabolites that are conjugated with glucuronic acid are passed in the urine
How is Dobutamine eliminated?
Excreted via the renal system; In urine the major excretion products are the conjugates of Dobutamine and the inactive derivative of Dobutamine (3-O- methyl Dobutamine)
What are the CNS side effects of Dobutamine?
Fever, Headache, Parasthesia
What is the resp. side effect of Dobut?
What are the CV side effects of Dobutamine (excluding Tachycardia, we will cover that separately!)?
Increased Ventricular Ectopy
How does administration of Dobutamine cause tachycardia? What dosage/infusion rate do you see this effect more prominently?
Usually elicited through HIGH infusion rates (>10mcg/kg/min) or infusions lasting over 72hrs.
Tachycardias may be more prominent in patients with Afib b/c Dobutamine increases the conduction velocity through the AV node!