Pharmacology - dobutamine

Pharmacology -  dobutamine 
A cardiac stimulant, it raises the contractility of the heart and, as a result, the output of the heart. Vasoconstriction is minimal, and it has a lessening effect on the rate at which the heart beats.

Mode of Action  
It primarily acts on beta 1-receptors, which results in an increase in cAMP that is mediated by G-proteins. This, in turn, causes an increase in calcium influx in the cardiac myocytes.
The beta 2-receptors are only marginally affected.

Absorption / Distribution / Elimination 

Inactivated by MAO and COMT, the drug is administered intravenously at a plasma half life of  two minutes.

Use in Clinical Settings 
Shock caused by the heart. Decompensated congestive heart failure.

Dirhythmias are one of the adverse effects.