Dopamine and Dextrose

Uses

Dextrose is administered as a parenteral nutrition solution in the treatment of carbohydrate depletion and hypoglycaemic coma. Because of its high dextrose content it is used in the treatment of cerebral edema, shock, circulatory collapse, unconsciousness and to correct hyperkalaemia with or without insulin.

Dopamine is recommended for the correction of haemodynamic imbalance present in- Acute hypotension or shock associated with myocardial infarction, endotoxic septicaemia, trauma and renal failure. As an adjunct after open heart surgery, where there is persistent hypotension after correction of hypovolaemia. In chronic cardiac decompensation as in congestive failure.

Dopamine and Dextrose is also used to associated treatment for these conditions: Arrhythmia, Caloric Deficit, Edema of the cerebrum, Metabolic Alkalosis, Hypoglycemic reaction, Blood Specimen Collection, Electrolyte replacement, Nutritional supplementation, Parenteral Nutrition, Parenteral rehydration therapy, Plasmapheresis, Positive cardiac inotropic effect, Total parenteral nutrition therapy, Urine alkalinization therapy, Fluid and electrolyte maintenance therapy

How Dopamine and Dextrose works

Glucose supplies most of the energy to all tissues by generating energy molecules ATP and NADH during a series of metabolism reactions called glycolysis. Glycolysis can be divided into 2 main phases where the preparatory phase is initiated by the phosphorylation of glucose by a hexokinase to form glucose 6-phosphate. The addition of the high-energy phosphate group activates glucose for subsequent breakdown in later steps of glycolysis and is the rate-limiting step. Products end up as substrates for following reactions, to ultimately convert C6 glucose molecule into two C3 sugar molecules. These products enter the energy-releasing phase where total of 4ATP and 2NADH molecules are generated per one glucose molecule. The total aerobic metabolism of glucose can produce up to 36 ATP molecules. This energy-producing reactions of glucose is limited to D-glucose as L-glucose cannot be phosphorlyated by hexokinase. Glucose can act as precursors to generate other biomolecules such as vitamin C. It plays a role as a signaling molecule to control glucose and energy homeostasis. Glucose can regulate gene transcription, enzyme activity, hormone secretion, and the activity of glucoregulatory neurons. The types, number and kinetics of glucose transporters expressed depends on the tissues and fine-tunes glucose uptake, metabolism, and signal generation in order to preserve cellular and whole body metabolic integrity .

Dosage

Dopamine and Dextrose dosage

The volume and rate of infusion of dextrose solution will depend upon the requirements of the individual patient and the judgement of the physician.

The maximum rate at which dextrose can be infused without producing glycosuria is 0.5 gm/kg/hr.

The usual recommended flow rate for adult is 10-35 drops per minute infused intravenously.

Intravenous-

Hyperkalaemia:

• Adult: 25-50 g combined with 10 units of regular insulin, administered over 30-60 minutes; may repeat if necessary. Alternatively, 25 g combined with 5-10 units of regular insulin infused over 5 minutes; may repeat if necessary.
• Child and infants: 0.5-1 g/kg (using 25% or 50% solution) combined with regular insulin (1 unit for every 4-5 g dextrose given); infuse over 2 hr, may repeat if necessary.

Intravenous-

Hypoglycaemia:

• Adult: 10-25 g (40-100 ml of 25% solution or 20-50 ml of 50% solution). Doses may be repeated in severe cases.
• Child: ≤6 mth: 0.25-0.5 g/kg/dose; >6 mth: 0.5-1 g/kg/dose. Doses may be repeated in severe cases. Max: 25 g/dose.

Oral-

Hypoglycaemia:

• Adult: 10-20 g as single dose; may repeat in 10 min if needed.
• Child: >2 yr: 10-20 g as single dose; may repeat in 10 min if needed.

Adult dose: Where appropriate, the circulating blood volume must be restored with a suitable plasma expander or whole blood, prior to administration of dopamine. Begin infusion of dopamine hydrochloride solution at dosage of 2 to 5 micrograms/kg/min in patients who are likely to respond to a modest increment of heart force and renal perfusion. In more seriously ill patients, begin infusion of dopamine hydrochloride solution at dosage of 5 micrograms/kg/min and increase gradually using 5 to 10 micrograms/kg/min increment up to 20 to 50 micrograms/kg/min as needed. If dosage in excess of 50 micrograms/kg/min are required, it is suggested that urine output should be checked frequently. In patients who do not respond to this doses, additional increments of dopamine may be given in an effort to achieve adequent blood pressure, urine flow and perfusion.For patients with severe, refractory, chronic congestive heart failure doses should be started on 0.5 to 2 micrograms/kg/min, and the dose increased by 1 to 3 micrograms/kg/min as urinary output increases.ECG, blood pressure and urine output should be monitored. Cardiac output and pulmonary wedge pressure should be monitored if possible.Children less than 12 years old: The safety and efficacy of dopamine in children under 12 years has not been established.Geriatric patients: No variation in dosage is suggested for geriatric patients. However, close monitoring is required for blood pressure, urine flow, and peripheral tissue perfusion.

It should not be administered by SC or IM route. Dextrose should be infused through the largest available peripheral vein.

Rate of administration: After dilution dopamine hydrochloride is administered intravenously through a suitable intravenous catheter or needle. An intravenous drip chamber or other suitable metering device is essential for controlling the rate of flow in drops per minute. Each patient must be individually titrated to the desired haemodynamic and/or renal response with dopamine hydrochloride. In titrating to the desired increase in systolic blood pressure, the optimum dosage rate for renal response may be exceeded, thus necessitating a reduction in rate after the haemodynamic condition is stabilized. Administration rate greater than 50 micrograms/kg/minute have safely been used in advanced circulatory decompensation states. If unnecessary fluid expansion is of concern, adjustment of drug concentration may be preferred over increasing the flow rate of a less concentrated dilution.

Side Effects

Venous thrombosis, phlebitis, hypovolemia, hypervolemia, dehydration, oedema, fever, mental confusion, unconsciousness, hyperosmolar syndrome, hyperglycaemia, hypokalaemia, acidosis, hypophosphataemia, hypomagnesemia, polyuria, glycosuria, ketonuria, nausea, diarrhoea, polydipsia, vein irritation, tissue necrosis, pulmonary oedema, tachypnoea.

The most frequent reported adverse reactions are ectopic beats, nausea, vomiting, tachycardia, anginal pain, palpitations, dyspnoea, headache, hypotension, hypertension and vasoconstriction. Other less frequent adverse reactions are aberrant ventricular conduction, bradycardia, piloerection, mydriasis, widened QRS complex, azotaemia and elevated blood pressure. Peripheral ischemic gangrene in patients with pre-existing vascular disease. Fatal ventricular arrhythmias have been reported on rare occasions.

Toxicity

Oral LD50 value in rats is 25800mg/kg. The administration of glucose infusions can cause fluid and/or solute overloading resulting in dilution of the serum electrolyte concentrations, over-hydration, congested states, or pulmonary oedema. Hypersensitivity reactions may also occur including anaphylactic/anaphylactoid reactions from oral tablets and intravenous infusions.

Precaution

Concentrated dextrose solution should not be infused rapidly or for a long period. It may be hazardous in patients with impaired hepatic or renal function and severe sepsis.

Care should be taken to avoid circulatory overload, particularly in patients with cardiac insufficiency. Caution must be exercised in the administration of these injections to patients receiving corticosteroids or corticotropin. These injections should be used with caution in patients with overt or subclinical diabetes mellitus.

Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration whenever solution and container permit. Do not administer unless solution is clear and seal is intact.

Dopamine hydrochloride should not be administered in the presence of uncorrected tachyarrhythmia or ventricular fibrillation. It is metabolized in the tissues and blood by monoamine oxidase (MAO) and catechol-O-methyltransferase (COMT). Dopamine hydrochloride and its metabolites are almost completely excreted in the urine. Patients who have been treated with monoamine oxidase inhibitors (MAOI) prior to the administration of dopamine will require substantially reduced dosages of later. The starting dose in such patients should be reduced to at least one-tenth (1/10) of the usual dose. Excess administration of potassium-free solutions may result in significant hypokalemia. The intravenous administration of these solutions can cause fluid and/or solute overloading resulting in dilution of serum electrolyte concentration, overhydration, congested states or pulmonary oedema. Closely monitoring is advised in patients with impaired renal and hepatic function.Hypovolaemia should be corrected where necessary prior to treatment with dopamine hydrochloride. If a disproportionate rise in diastolic blood pressure (i.e. a marked decrease in pulse pressure) is observed, the infusion rate should be decreased and the patients observed carefully for further evidence of predominant vasoconstriction activity, unless such effect is desired. Dopamine hydrochloride infusion should be withdrawn gradually, to avoid unnecessary hypotension. Patients with a history of peripheral vascular disease (e.g. atherosclerosis, arterial embolism, Raynaud's disease, cold injury, diabetic endarteritis and Buerger's disease) should be closely monitored for any changes in color or temperature of the skin in the extremities. If ischemia occurs and is thought to be the result of vasoconstriction, the benefits of continued dopamine hydrochloride infusion should be weighed against the risk of possible necrosis. These changes may be reversed by either decreasing the rate or discontinuing the infusion. Dopamine hydrochloride in 5% dextrose solution should be infused into a large vein whenever possible to prevent the possibility of infiltration of perivascular tissue adjacent to the infusion site. Extravasations may cause necrosis and sloughing of the surrounding tissue. Ischaemia can be reversed by infiltration of the affected area with 10-15ml of saline containing 5 to 10mg Phentolamine mesylate. Dopamine hydrochloride should be used with extreme caution in patients inhaling cyclopropane or halogenated hydrocarbon anaesthetics due to the arterial arrhythmogenic potential. Dextrose solutions should be used with caution in patients with known subclinical or over diabetes mellitus.

Interaction

There is no drug drug interaction and none well documented.

The action of dopamine hydrochloride is potentiated by monoamine oxidase inhibitors (MAOI's). The concurrent administration of cyclopropane or halogenated hydrocarbon anesthetics may cause ventricular arrhythmias. The cardiac effects of dopamine hydrochloride are antagonized by β - adrenergic blocking agents such as Propranolol and Metoprolol. The ergot alkaloids should be avoided because of the possibility of excessive vasoconstriction. Tricyclic antidepressants and guanethidine may potentiate the pressor response to dopamine hydrochloride. Hypotension and bradycardia have been observed in patients receiving Phenytoin. Dopamine hydrochloride may increase the effect of diuretic agents. Peripheral vasoconstriction may be antagonized by α - adrenergic blocking agents, such as Phentolamine. Other vasodilators may also be useful in patients with heart failure, allowing greater inotropic and renal effects without the associated vasoconstriction. Care must be taken to avoid hypotension.

Volume of Distribution

The mean volume of distribution after intravenous infusion is 10.6L.

Elimination Route

Polysaccharides can be broken down into smaller units by pancreatic and intestinal glycosidases or intestinal flora. Sodium-dependent glucose transporter SGLT1 and GLUT2 (SLC2A2) play predominant roles in intestinal transport of glucose into the circulation. SGLT1 is located in the apical membrane of the intestinal wall while GLUT2 is located in the basolateral membrane, but it was proposed that GLUT2 can be recruited into the apical membrane after a high luminal glucose bolus allowing bulk absorption of glucose by facilitated diffusion . Oral preparation of glucose reaches the peak concentration within 40 minutes and the intravenous infusions display 100% bioavailability.

Half Life

The approximate half-life is 14.3 minutes following intravenous infusion. Gut glucose half-life was markedly higher in females (79 ± 2 min) than in males (65 ± 3 min, P < 0.0001) and negatively related to body height (r = -0.481; P < 0.0001).

Clearance

The mean metabolic clearance rate of glucose (MCR) for the 10 subjects studied at the higher insulin level was 2.27 ± 0.37 ml/kg/min at euglycemia and fell to 1.51±0.21 ml/kg/ at hyperglycemia. The mean MCR for the six subjects studied at the lower insulin level was 1.91 ± 0.31 ml/kg/min at euglyglycemia.

Elimination Route

Glucose can be renally excreted.

Pregnancy & Breastfeeding use

Pregnancy Category C. Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.

Animal studies have revealed no evidence of teratogenic effects from dopamine hydrochloride. The drug may be used in pregnant women when in the judgment of the physician the expected benefits outweigh the potential for risk to the fetus. It is not known if dopamine hydrochloride is excreted in breast milk, nor is the effect on the infant known. It is not recommended for breast-feeding mothers unless the expected benefits outweigh any potential risks

Contraindication

Concentrated dextrose solution is contraindicated in patients with Glucose-Galactose Malabsorption Syndrome and severe hydration. The infusion of hypertonic dextrose injections is contraindicated in patients having intracranial or intraspinal hemorrhage, in patients who are severely dehydrated, in patients who are anuric, and in patients in hepatic coma. Solutions containing dextrose may be contraindicated in patients with known allergy to corn or corn products.

Dopamine hydrochloride is contraindicated in patients with known hypersensitivity to dopamine or any of its ingredients. It should not be used in patients with phaeochromocytoma, uncorrected tachyarrhythmias, or ventricular fibrillation. Dextrose solution without electrolytes should not be administered simultaneously with blood through the same infusion set because of the possibility of pseudoagglutination of red cells.

Acute Overdose

Reevaluate patient's condition and institute appropriate symptomatic treatment.

In case of accidental overdosage, as evidenced by excessive blood pressure elevation, reduce the rate of administration or temporarily discontinue dopamine hydrochloride until the patients condition stabilized. Since the duration of action of dopamine hydrochloride is quite short, no additional measures are usually necessary. If these measures fail to stabilize the patient's condition, use of the short-acting α-adrenergic blocking agent such as Phentolamine should be considered.

Storage Condition

Store at 25°C.

Store below 25°C and protect from light.

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