dopamine (Inotropin, Dopastat)
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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
- treatment of hypotension persistent after adequate fluid volume replacement
- refractory acute heart failure
- sinus bradycardia
- 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
- onset of action < 5 minutes
- metabolized by liver, kidney, adrenergic nerve terminals, & plasma MAO & COMT to homovanillic acid (HVA) & norepinephrine
- eliminated in the urine
- 1/2life is 2-10 minutes
elimination via plasma
1/2life = 2-10 minutes
Adverse effects
- common (> 10%)
- less common (1-10%)
- bradycardia, hypertension, gangrene of the extremities & ears*
- uncommon (< 1%)
- ectopic heartbeats, vasoconstriction, anxiety, piloerection, decreased urine output, azotemia
- others:
- increased ventricular response to atrial fibrillation, contains sulfite (asthmatics may be sensitive)
* surprising frequency, but as written in ref 3
- drug adverse effects of adrenergic receptor agonists
- drug adverse effects of beta-adrenergic receptor agonists
- drug adverse effects of alpha-adrenergic receptor agonists
- drug adverse effects of sympathomimetic(s)
Drug interactions
- beta blockers antagonize effects of dobutamine
- MAO inhibitors increase the hypertensive response by inhibiting dopamine metabolism
- phenytoin when coadministered IV may result in bradycardia & hypotension
Mechanism of action
- directly stimulates beta-1 adrenergic receptors
- directly stimulates dopaminergic receptors, causing vaso- dilation in renal, mesenteric, coronary & intracerebral beds
- directly stimulates alpha-1 adrenergic receptors causing vasoconstriction
- 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)
- 1-3 ug/kg/min
- hemodynamic effects
- positive inotrope
- may facilitate AV conduction
* utility of renal dose has been questioned[5]
More general terms
- catecholamine
- alpha adrenergic receptor agonist
- beta-1 adrenergic receptor agonist
- vasoconstrictor agent or vasopressor
- inotropic agent
Additional terms
- dopamine metabolism
- dopamine receptor
- dopamine transporter (solute carrier family 6 member 3, DA transporter, DAT, DAT1, SLC6A3)
- dopaminergic neuron
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
- ↑ 5.0 5.1 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: https://www.ncbi.nlm.nih.gov/pubmed/11505120
- ↑ 6.0 6.1 Medical Knowledge Self Assessment Program (MKSAP) 17, American College of Physicians, Philadelphia 2015