Mechanism of action
Dopamine and alpha and beta adrenoreceptor agonist. Effects on receptors are dose dependent.
- Low dose (1-5 micrograms/kg/min): predominantly dopamine receptors (D1 and D2) - positive inotropic effect, increased renal perfusion and renal output.
- Intermediate dose (5-10 micrograms/kg/min): predominantly on beta receptors - positive inotropic effect, increased heart rate, cardiac output and renal blood flow.
- High dose (>10 micrograms/kg/min): predominantly on alpha adrenoreceptors as well as beta adrenoreceptors causing vasoconstriction, increased blood pressure, increased heart rate, heart contractility and cardiac output.
Indications and dose
Side-effects
Arrhythmias
Pulmonary artery vasoconstriction
Splanchnic ischaemia
Inhibits TSH and prolactin release
Contraindications
Pheochromocytoma
Pharmacokinetics
Onset: 5 minutes
Duration: 10 minutes
Bioavailability: N/A
Metabolism: renal, hepatic, plasma (MAO and COMT)
Half-life of elimination: 2 minutes
Excretion: Urine
Directions for administration
Dilute with 5% glucose or 0.9% sodium chloride.
Incompatible with bicarbonate.
Medicinal forms
1 vial = 200 mg in 5 ml (1 ml=40 mg)
References
