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dopamine (Inotropin, Dopastat)
Function:
- neurotransmitter in the central nervous system, mostly inhibitory, sometimes excitatory
- produced by neurons in the ventral tegmental area & the substantia nigra
- see dopaminergic system
- also released by chromaffin cells of the adrenal medulla in response to stress
- effects mediated by dopamine receptors
Pharmacology:
Tradenames: Inotropin, Dopastat.
Indications:
1) treatment of hypotension persistent after adequate fluid volume replacement
2) refractory acute heart failure
3) sinus bradycardia
3) hepatorenal syndrome
Dosage: 400 mg in 250 mL D5W (1600 ug/mL) at 2-20 ug/kg/min. 70 kg: 13 mL/hr = 5 ug/kg/min. Vials: 40 mg/mL (5 mL), 80 mg/mL (5 mL).
Pharmacokinetics:
1) onset of action < 5 minutes
2) metabolized by liver, kidney, adrenergic nerve terminals, & plasma MAO & COMT to homovanillic acid (HVA) & norepinephrine
3) eliminated in the urine
4) 1/2life is 2-10 minutes
Adverse effects:
1) common (> 10%)
- chest pain
- headache
- nausea/vomiting
- dyspnea
- hypotension
- palpitations
- tachycardia
- ventricular arrhythmias
2) less common (1-10%)
- bradycardia, hypertension, gangrene of the extremities & ears*
3) uncommon (< 1%)
- ectopic heartbeats, vasoconstriction, anxiety, piloerection, decreased urine output, azotemia
4) others:
- increased ventricular response to atrial fibrillation, contains sulfite (asthmatics may be sensitive)
* surprising frequency, but as written in ref 3
Drug interactions:
1) beta blockers antagonize effects of dobutamine
2) MAO inhibitors increase the hypertensive response by inhibiting dopamine metabolism
3) phenytoin when coadministered IV may result in bradycardia & hypotension
Mechanism of action:
1) directly stimulates beta-1 adrenergic receptors
2) directly stimulates dopaminergic receptors, causing vaso- dilation in renal, mesenteric, coronary & intracerebral beds
3) directly stimulates alpha-1 adrenergic receptors causing vasoconstriction
4) agonist activity [6]
- 1-3 ug/kg/min
- dopaminergic receptor agonist (renal dosage*)
- 2-5 ug/kg/min
- beta-1 adrenergic receptor agonst (inotropic effect)
- 5-10 ug/kg/min
- alpha-1 adrenergic receptor agonist (peripheral vasoconstriction)
5) hemodynamic effects
a) positive inotrope
b) may facilitate AV conduction
* utility of renal dose has been questioned [5]
Interactions
molecular events
drug adverse effects (more general classes)
Related
dopamine metabolism
dopamine receptor
dopamine transporter (solute carrier family 6 member 3, DA transporter, DAT, DAT1, SLC6A3)
dopaminergic neuron
General
alpha adrenergic receptor agonist
beta-1 adrenergic receptor agonist
catecholamine
inotropic agent
vasoconstrictor agent or vasopressor
Properties
AGONIST-FOR: alpha adrenergic receptor
MISC-INFO: elimination route PLASMA
1/2life 2-10 MINUTES
pregnancy-category C
safety in lactation -
Database Correlations
PUBCHEM correlations
References
- The Pharmacological Basis of Therapeutics, 9th ed.
Gilman et al, eds. Permagon Press/McGraw Hill, 1996
- Manual of Medical Therapeutics, 28th ed, Ewald &
McKenzie (eds), Little, Brown & Co, Boston, 1995, pg 123
- Kaiser Permanente Northern California Regional Drug
Formulary, 1998
- Drug Information & Medication Formulary, Veterans Affairs,
Central California Health Care System, 1st ed., Ravnan et al
eds, 1998
- Journal Watch 21(19):152-53, 2001
Kellum JA, M Decker J.
Use of dopamine in acute renal failure: a meta-analysis.
Crit Care Med 29:1526, 2001
PMID: 11505120
- Medical Knowledge Self Assessment Program (MKSAP) 17,
American College of Physicians, Philadelphia 2015