Brands, Medical Use, Clinical Data
- Cardiotonic Agents
Brands / Synonyms
DA; Deoxyepinephrine; Dopamin; Dopamine; Dopamine HCl; Dophamine; Hydroxytyramin; Hydroxytyramine; Intropin; Oxytyramine; Revimine
For the correction of hemodynamic imbalances present in the shock syndrome due to myocardial infarction, trauma, endotoxic septicemia, open-heart surgery, renal failure, and chronic cardiac decompensation as in congestive failure
Dopamine is a natural catecholamine formed by the decarboxylation of 3,4-dihydroxyphenylalanine (DOPA). It is a precursor to norepinephrine in noradrenergic nerves and is also a neurotransmitter in certain areas of the central nervous system, especially in the nigrostriatal tract, and in a few peripheral sympathetic nerves. Dopamine produces positive chronotropic and inotropic effects on the myocardium, resulting in increased heart rate and cardiac contractility. This is accomplished directly by exerting an agonist action on beta-adrenoceptors and indirectly by causing release of norepinephrine from storage sites in sympathetic nerve endings.
Mechanism of Action
Dopamine is a precursor to norepinephrine in noradrenergic nerves and is also a neurotransmitter in certain areas of the central nervous system. Dopamine produces positive chronotropic and inotropic effects on the myocardium, resulting in increased heart rate and cardiac contractility. This is accomplished directly by exerting an agonist action on beta-adrenoceptors and indirectly by causing release of norepinephrine from storage sites in sympathetic nerve endings.
Dopamine is rapidly absorbed from the small intestine.
LD50 oral mice = 1460 mg/kg, LD50 oral rats = 1780 mg/kg. Spasm or closing of eyelids, nausea, vomiting, cardiac arrhythmias, involuntary movements of the body including the face, tongue, arms, hand, head, and upper body; hypotension, haemolytic anaemia, urinary retention, duodenal ulcer, sialorrhea, ataxia, abdominal pain, dry mouth, nightmares, tachypnoea, bruxism, confusion, and insomnia.
Biotrnasformation / Drug Metabolism
Biotransformation of dopamine proceeds rapidly to yield the principal excretion products, 3-4-dihydroxy-phenylacetic acid (DOPAC) and 3-methoxy-4-hydroxy-phenylacetic acid (homovanillic acid, HVA).
Dopamine HCl should not be used in patients with pheochromocytoma. Dopamine HCl should not be administered to
patients with uncorrected tachyarrhythmias or ventricular fibrillation.
Because dopamine is metabolized by monoamine oxidase (MAO), inhibition of this enzyme prolongs and potentiates the
effect of dopamine. Patients who have been treated with MAO inhibitors within two to three weeks prior to the
administration of dopamine HCl should receive initial doses of dopamine HCl no greater than one-tenth (1/10) of the
Concurrent administration of low-dose dopamine HCl and diuretic agents may produce an additive or
potentiating effect on urine flow.
Tricyclic antidepressants may potentiate the cardiovascular effects of adreneric agents.
Cardiac effects of dopamine are antagonized by beta-adrenergic blocking agents, such as propranolol and
metoprolol. The peripheral vasoconstriction caused by high doses of dopamine HCl is antagonized by alpha-adrenergic
blocking agents. Dopamine-induced renal and mesenteric vasodilation is not antagonized by either alpha-or
beta-adrenergic blocking agents.
Butyrophenones (such as haloperidol) and phenothiazines can suppress the dopaminergic renal and mesenteric
vasodilation induced with low dose dopamine infusion.
Cyclopropane or halogenated hydrocarbon anesthetics increase cardiac autonomic irritability and may
sensitize the myocardium to the action of certain intravenously administered catecholamines, such as dopamine. This
interaction appears to be related both to pressor activity and to beta-adrenergic stimulating properties of these
catecholamines and may produce ventricular arrhythmias and hypertension. Therefore, EXTREME CAUTION should be
exercised when administering dopamine HCl to patients receiving cyclopropane or halogenated hydrocarbon anesthetics.
It has been reported that results of studies in animals indicate that dopamine-induced ventricular arrhythmias during
anesthesia can be reversed by propranolol.
The concomitant use of vasopressors, vasoconstricting agents (such as ergonovine) and some oxytocic drugs may
result in severe hypertension.
Administration of phenytoin to patients receiving dopamine HCl has been reported to lead to hypotension and
bradycardia. It is suggested that in patients receiving dopamine HCl, alternatives to phenytoin should be used if
anticonvulsant therapy is needed.