Dobutamine
2
Mechanism Synthetic analog of dopamine that stimulates 1 -adrenoceptors and to a lesser extent 2 - and 1 -adrenoceptors. 1 : (G s , ↑ cAMP) →↑ inotropy and HR (although for unclear reasons, inotropic effects more pronounced). 2 : (G s , ↑ cAMP) → vascular smooth muscle relaxation. 1 : (PIP 2 cascade) → vascular smooth muscle contraction. Net effect is ↑ cardiac contractility and ↑ CO. Tends to mildly ↓ SVR due to counterbalancing of 2 and 1 effects; overall effect on BP is variable and depends on balance between ↑ CO and ↓ SVR. Despite ↑ HR, dobutamine can actually ↓ myocardial oxygen demand by ↑ inotropy and ↓ SVR. Clinical Acute management of decompensated congestive heart failure. After 1 week of continuous therapy, downregulation of receptors will ↓ efficacy of drug. Side Effects Arrhythmias. Possible hypotension. Contraindic. Hypotension. Hypertrophic cardiomyopathy (worsens outflow tract obstruction). Metabolism IV. Inactivated by COMT and MAO enzymes. Notes DOBUTAMINE (Dobutrex) direct sympathomimetic 4
-
Upload
daniel-mendoza -
Category
Documents
-
view
15 -
download
0
description
Direct Sympathomomic
Transcript of Dobutamine
Mechanism Synthetic analog of dopamine that stimulates �1-adrenoceptors and to a lesser extent �2- and �1-adrenoceptors.
�1: (Gs, ↑ cAMP) → ↑ inotropy and HR (although for unclear reasons, inotropic effects more pronounced).�2: (Gs, ↑ cAMP) → vascular smooth muscle relaxation.�1: (PIP2 cascade) → vascular smooth muscle contraction.Net effect is ↑ cardiac contractility and ↑ CO. Tends to mildly ↓ SVR due to counterbalancing of �2 and
�1 effects; overall effect on BP is variable and depends on balance between ↑ CO and ↓ SVR. Despite↑ HR, dobutamine can actually ↓ myocardial oxygen demand by ↑ inotropy and ↓ SVR.
Clinical Acute management of decompensated congestive heart failure. After �1 week of continuous therapy,downregulation of receptors will ↓ efficacy of drug.
Side Effects Arrhythmias. Possible hypotension.
Contraindic. Hypotension. Hypertrophic cardiomyopathy (worsens outflow tract obstruction).
Metabolism IV. Inactivated by COMT and MAO enzymes.
Notes
DOBUTAMINE (Dobutrex) direct sympathomimetic 4
PharmaCard_01.qxd 10/23/09 11:28 AM Page 4
+
–
dobutamine
vasodilation
arterioles
heart
inotropy↑
ADREN
DOBUTAMINE
PharmaCard_01.qxd 10/23/09 11:28 AM Page 4b
