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Dobutamine: |
Synthetic Sympathomimetic Chatecholamine |
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...Given to improve cardiac output. |
b1 > b1 > a |
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INFUSION DOSING |
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Increase the infusion 2 mcg/kg/min every 15 minutes as needed (or whenever its convenient). |
2-40 mcg/kg/min |
Used
for severe acute-on-chronic CHF, AMI s/p cardiac surgery, cardiogenic
shock, excess b-blockade.
It is used particularly when a strong inotropic effect is desired,
without severely effecting HR and BP. The
reason for Dobutamine's relative lack of chronotropic effect is not known.
Half
life: very short, effects
end only 2-5 minutes after IV infusion is stopped.
Side Effects: AMI, arrhythmias, HTN, N/V, HA.
Contraindicated:
Tachydysrhythmias, hypovolemia or sys <100, IHSS, and poison-induced shock.
Dopamine
is preferred when there is impaired renal blood flow, such as severe CHF.
Dobutamine
is preferred if a pt. is tachycardic, or has ventricular arrhythmias (or
risk). (Though dobutamine can at times cause a reflex tachycardia when its
vasodilatory effects are present). Dobutamine
can cause b-receptor
downgrading, especially after 72 hours, and will of course be less effect, or
even ineffective, if b-receptors
have already been downgraded as in severe CHF, when a-receptors
have been upgraded. Dobutamine does
not effect DA receptors as dopamine does, nor does it directly cause the release
of norepinephrine.
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