Dopamine
26/10/10
Class - naturally occurring catecholamine
Mechanism of Action – dopamine and adrenoreceptor agonist
- 1-5mcg/kg/min - D 1 & 2 receptors (inotropy
- 5-10mcg/kg/min - direct & indirect effects on beta receptors -> inotropy
- >10mcg/kg/min - alpha effects -> vasoconstriction
- immediate precursor to noradrenaline
- neurotransmitter in the nervous system
- increases adosterone secretion
Dose - 1-20mcg/kg/min (onset: 5min, duration: 10min)
Pharmaceutics – ampoule 200mg/5mL + meta-bisulfite
Indications – low Q states
Adverse Effects
-
arrhythmias
pulmonary artery vasoconstriction
caution with MAO-I and phenytoin
N+V
immune dysfunction
decreased GI oxygenation in shock states
diuresis in patients who are hypovolaemia
inhibits TSH and prolactin release
PK
Absorption - IV
Distribution
Metabolism – hepatic and adrenergic nerve endings (MAO and COMT)
Elimination – urinary, T1/2 = 2min
Evidence
Myles, P.S et al (1993) “’Renal dose’ dopamine on renal function following cardiac surgery”
Anaes. Intens. Care 21:56
- CABG patients
- dopamine 200mcg/min vs placebo for 24 hours
-> no improvement in CrCl
Jeremy Fernando (2011)
Duke G.J. et al (1994) “Renal support in critically ill patients: low-dose dopamine vs low dose
dobutamine?” Critical Care Medicine, 22:(12), page 1919-25
- RCT
- placebo vs dopamine vs dobutamine
-> increased U/O with dopamine but no change in CrCl
-> improved CrCl while no change in U/O with dobutamine compared with placebo
-> increased urine output is not synonymous with improved renal function
ANZICS (2000, Lancet)
- RCT – dopamine vs placebo
- no change in Cr, ICU LOS, hospital LOS, RRT
-> don’t use low dose dopamine for renal protection
De Backer, D. et al (2010) “Comparison of dopamine and norepinephrine in the treatment of
shock” N Engl J Med, 362:779-789
- MRCT
- n = 858
- 50% of patients died in both groups
-> no difference in mortality rates (ICU, 6 months and 12 months)
-> more arrhythmias
-> increased risk of death @ 28 days with dopamine + cardiogenic shock
Patel, G.P. et al (2010) “Efficacy and safety of dopamine versus norepinephrine in
management of septic shock” Shock 33:375-380
- SRCT
- n = 252 with septic shock in a medical ICU
-> more arrhythmias in dopamine group
-> no difference in 28 day mortality
Jeremy Fernando (2011)