Dopamine intravenous infusion

Dopamine, a vasodilator, has been widely used for treatment of acute circulatory failure. However, since dopamine is rapidly metabolized when administered orally, its use has been limited to intravenous infusion. Murata et al., studied the bioavailability and the pharmacokinetics of orally administered dopamine (DA). The oral administration of DA to dogs resulted in an absolute bioavailability of approximately 3%. To minimize the extensive first-pass metabolism of DA, a dopamine prodrug, V-(/V-acetyl-l-mcLhionyl)-o,o-bis(cLhoxycarbonyl)dopamine (TA-870), was synthesized [28] (Fig. 6). Since DA is a substrate for both mono-... 

Soliakov L, Gallagher T, Wonnacott S (1995) Anatoxin-a-evoked [ H]dopamine release from rat striatal synaptosomes. Neuropharmacology 34 1535-1541 Soliakov L, Wonnacott S (1996) Voltage-sensitive Ca channels involved in nicotinic receptor-mediated [ H]dopamine release from rat striatal synaptosomes. J Neurochem 67 163-170 Sorge R, Clarke PB (2007) Slow/low intravenous infusions of nicotine in rats a better model of smoking Soc Neurosci Abst 37 273.17... 

Dose. Initially 2 to 5 pg/kg/min of dopamine hydrochloride, by intravenous infusion. 

Half-life less than 3 h. Dosing at intervals equal to the t/ would be so frequent as to be unacceptable, and the answer is to use continuous intravenous infusion if the tj is very short, e.g. dopamine t), 2 min steady-state plasma concentration will be reached in... 

Memoli studied 9 patients being treated for metastatic renal cancer with a continuous intravenous infusion of rIL-2. All nine of the patients had undergone a unilateral nephrectomy and may have had baseline renal impairment. All 9 experienced a progressive decline in creatinine clearance. Low dose dopamine seemed to improve creatinine clearance after renal impairment had occurred [41]. 

We then examined the effect of FM574 on gastric emptying in two gastropare-sis models, induced by intraduodenal instillation of oleic acid and intravenous infusion of dopamine. Lipid or free fatty acid in the lumen of the intestine is a potent inhibitor of gastric emptying [29], and this inhibition is thought to be... 

Due to the on/off phenomena and concerns about the exact role of dopamine s contribution to free radical generation and tissue damage, most practitioners use levodopa only when the symptoms of PD cause functional impairment. When levodopa levels are maintained constant by intravenous infusion, dyskinesias and fluctuations are greatly reduced, and the clinical improvement is maintained for up to several days after returning to oral levodopa dosing. A sustained-release formulation and division of the total daily dose into more frequently administered portions have been used to overcome the on/off phenomenon. 

The operation was postponed, and the patient was given intravenous epinephrine, dexametha-sone, diphenhydrcunine. and fluids over the next 2 hours. Blood pressure was restored and maintained by intravenous infusion of dopamine. In the intensive care unit, electrocardiography suggested acute cardiac injury the patient had no history of angina pectoris or heart disease. Suh.sequent chest x-ray revealed a normal heart size with bilateral pulmonary edema. 

Dopamine also stimulates cardiac Pi-receptors through both direct and indirect mechanisms. It is used to correct hemodynamic imbalances induced by conditions such as shock, myocardial infarction, trauma, or congestive heart failure. As a catechol and primary amine, dopamine is rapidly metabolized by COMT and MAO and, similar to dobutamine, has a short duration of action with no oral activity. It is administered as an intravenous infusion. 

B. Continuous intravenous infusion. Administer a loading dose of 5-6 mg/kg IV over 1 hour (not to exceed 50 mg/min children, 1 mg/kg/min), followed by maintenance Infusion of 0.5-3 mg/kg/h titrated to the desired effect. For treatment of status epilepticus, use loading dose of 5-15 mg/kg given by IV infusion over 1 to 2 hours, monitor blood pressure (vasopressor support may be required eg, dopamine) and provide respiratory support, and follow with maintenance Infusion. Electroencephalographic achievement of burst suppression usually occurs with a semm pentobarbital concentration of 25-40 mcg/mL. 

A 38-year-old man was found in his bed deeply comatose and it was suspected that he had taken amlodipine 630 mg, zopiclone 300 mg, and uncertain amounts of citalopram and paracetamol at least 4 hours earlier. He was given activated charcoal, intravenous boluses of glucagon and calcium, and dopamine by infusion, followed by noradrenaline by infusion. Because of persistent hypotension and heart failure he was given levosimendan and the dobutamine was withdrawn. After 90 minutes his cardiac function had improved. The dose of levosimendan was increased and continued for 24 hours, when his lactic acidosis resolved. 

Intravenous infusion of dopamine hydrochloride at 1.6 mg/mL in 5% w/v glucose solution. Infusion ... 

Cardiovascular effects of Infusion of norepinephrine, epinephrine, Isoproterenol, and dopamine in humans. Infusions were made intravenously during the time indicated by the broken lines. Heart rate is given in beats per minute, blood pressure in millimeters of mercury, and peripheral resistance in arterial blood pressure. (Reprinted with permission from Allwood MJ, Cobbald AF, and Ginsburg J. Peripheral vascular effects of noradrenaline, isopropyl-noradrenaline, and dopamine. Br Med Bull 19 132, 1963. Reproduced by permission of the Medical Department, The British Council. 

Intravenous administration of dopamine promotes vasodilation of renal, splanchnic, coronary, cerebral, and perhaps other resistance vessels, via activation of Di receptors. Activation of the Di receptors in the renal vasculature may also induce natriuresis. The renal effects of dopamine have been used clinically to improve perfusion to the kidney in situations of oliguria (abnormally low urinary output). The activation of presynaptic D2 receptors suppresses norepinephrine release, but it is unclear if this contributes to cardiovascular effects of dopamine. In addition, dopamine activates Bj receptors in the heart. At low doses, peripheral resistance may decrease. At higher rates of infusion, dopamine activates vascular a. receptors, leading to vasoconstriction, including in the renal vascular bed. Consequently, high rates of infusion of dopamine may mimic the actions of epinephrine. 

Neurokinin 1 (NKiJ-receptor antagonists have antiemetic properties that are mediated through central blockade in the area postrema. Aprepitant (an oral formulation) is a highly selective Nl -receptor antagonist that crosses the blood-brain barrier and occupies brain NKj receptors. It has no affinity for serotonin, dopamine, or corticosteroid receptors. Fosaprepitant is an intravenous formulation that is converted within 30 minutes after infusion to aprepitant. 

These investigators subsequently demonstrated the clinical utility of intravenous dopamine infusions in treating patients with hypotension or shock unresponsive to plasma volume expansion. This provided the basis for a small pharmaceutical firm to bring dopamine to market in the early 1970s. 

A report from Italy has suggested that intravenous saline 0.4% before and after administration of the contrast medium, an infusion of dopamine 3 micrograms/kg/ minute for 24 hours after the contrast medium, intravenous furosemide 80 mg 30 minutes before the contrast medium, or intravenous mannitol (20%) 250 ml 1 horn-before and 1 hour after the contrast medium each prevented the reduction in renal function caused by the nonionic agents iobitridol, ioversol, or iodixanol (193). However, the protocol of the study was not described, and previous studies have shown that dopamine, furosemide, and mannitol do not offer good protection against contrast media-induced nephrotoxicity. On the other hand, volume expansion with intravenous saline has been found to offer some protection (190). 

The adverse effects of intravenous procainamide (400 mg up to three times infused over 10 minutes) have been reported in 60 adults with atrial flutter or fibrillation in a comparison with ibutihde (2). The adverse effects were headache in 11%, hypotension in 11%, flushing in 3.1%, dizziness in 3.1%, and hypesthesia in 3.1%. The mean fall in systolic blood pressure was about 20 mmHg and occurred at 30-35 minutes after infusion the corresponding fall in diastolic blood pressure was 10 mmHg. However, in seven patients there was severe hypotension, with a fall in diastolic blood pressure of up to 67 mmHg in three cases withdrawal of the infusion was required and these patients were treated with intravenous fluids, dopamine, or both. In the severe cases the hypotension occurred during or immediately after the infusion of procainamide. 

Epinephrine is well absorbed after oral administration but is rapidly inactivated in the gut mucosa. When intravenously injected or infused, the onset of drug effect is rapid (within 5 min for dopamine and 3-10 min for epinephrine) and the duration of drug effect is short (10 min for dopamine, 1 or 2 min for norepinephrine, and 15 min to hours for epinephrine depending on route of administration). Exogenous catecholamine in the circulation is rapidly and efficiently taken up by adrenergic neurons. Catecholamine is metabolized by monoamine oxidase, which is localized largely in the outer membrane of neuronal mitochondria, and by catechol-0-methyl transferase, which is found in the cytoplasm of most animal tissues, particularly the kidneys and the liver. 

Treatment is basically symptomatic and supportive no specific antidotes are available. Artificial ventilation with 100% humidified oxygen is necessary in cases of respiratory distress. If patient is cyanotic and cyanosis does not respond to oxygen administration, methemoglobin levels should be determined. Methemoglobinemia can be treated by intravenous administration of methylene blue. Support of cardiovascular function may also be required. Bladder damage can be determined by urinalysis. Hypotension may be treated with isotonic intravenous fluids. Dopamine or norepinephrine may be used if hypotension does not respond to infusion of fluids. Convulsions may be treated with intravenous benzodiazepines (diazepam or loraze-pam) phenobarbital may be used if the convulsions are recurrent. Because chlordimeform is a monoamine oxidase inhibitor, foods with large amounts of... 

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