| Indication | 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 |
| Pharmacodynamics | 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. In the brain, dopamine actas as an agonist to the five dopamine receptor subtypes (D!, D2, D3, D4, D5). |
| Absorption | Dopamine is rapidly absorbed from the small intestine. |
| Volume of distribution | Not Available |
| Protein binding | No information currently available on protein binding. |
| 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). |
| Route of elimination | It has been reported that about 80% of the drug is excreted in the urine within 24 hours, primarily as HVA and its sulfate and glucuronide conjugates and as 3,4-dihydroxyphenylacetic acid. A very small portion is excreted unchanged. |
| Half life | 2 minutes |
| Clearance | Not Available |
| Toxicity | 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. |