DOBUTAMINE

“DOBUTREX”

1) Therapeutic drug action & mechanism(pharmacology)

• Synthetic catecholamine

• Cardiospecific [acts almost exclusively on b₁-receptors]

• Causes i) Inotrope [b₁-receptors]

ii) Chronotrope [b₁-receptors]—at higher dosages

iii) vasodilation [b₂-receptor]—mild effect

2) Indications

• Short term treatment of cardiac failure post MI or cardiac surgery or during weaning off CPB to increase cardiac output

3) Effects on organs—side effects

• Systemic vasodilation

4) Toxic effects/ precautions with administration

• Increase in heart rate or blood pressure

• Increased ectopic activity

5) Contraindications

• Idiopathic hypertrophic subaortic stenosis

6) Reversal, antagonism or antidote

• Discontinue infusion as has short half life

7) Loading dose, maintenance dose, frequency & method of administration

• 250 mg vial: dilute in flask of D5W

• Normal dose 2.5-10 mg/Kg/min rarely up to 40 mg/Kg/min

• Can be given via peripheral line if necessary

8) Drug’s metabolism—Drug’s excretion—Half life (pharmacokinetics)

• Onset of action 1-2 min; peak effect within 10min

• Plasma half life is 2 min

• metabolites are excreted via kidneys

9) Important drug interactions

• Myocardium can be sensitised to the effects of dobutamine in presence of anaesthetic gaseous agents

• Interacts with Decadron, Gentamycin, Isuprel, Morphine, Sodium bicarbonate