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 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).
LD<sub>50</sub> oral mice = 1460 mg/kg, LD<sub>50</sub> 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.
Dopamine is rapidly absorbed from the small intestine.
2 minutes
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.
For the palliative treatment of mild to moderate dementia of the Alzheimer's type.
Donepezil is a piperidine derivative that is a centerally active, reversible inhibitor of acetylcholinesterase. This drug is structurally unrelated to other anticholinesterase agents. Donepezil's proposed mechanism of action involves the reversible inhibition of cholinesterases (eg. acetylcholinesterase), which prevents the hydrolysis of acetycholine, and leads to an increased concentration of acetylcholine at cholinergic synapses. Evidence suggests that the anticholinesterase activity of donepezil is relatively specific for acetylcholinesterase in the brain.
Symptoms of overdose include severe nausea, vomiting, salivation, sweating, bradycardia, hypotension, respiratory depression, collapse and convulsions. Increasing muscle weakness is a possibility and may result in death if respiratory muscles are involved.
Donepezil is well absorbed with a relative oral bioavailability of 100% and reaches peak plasma concentrations in 3 to 4 hours.
70 hours
Donepezil is both excreted in the urine intact and extensively metabolized to four major metabolites, two of which are known to be active, and a number of minor metabolites, not all of which have been identified.
* 12 L/kg
* apparent plasma cl=0.13 L/hr/kg