Dopamine Hydrochloride Injection

DOPAMINE HYDROCHLORIDE INJECTION USP

 

Presentation

DOPAMINE HYDROCHLORIDE INJECTION USP 40 mg/ml, 5 ml ampoules. Each ml contains 40 mg dopamine hydrochloride, 1.0 mg sodium metabisulphite in water for injections. The solution is clear and slightly yellow and is intended for preparation of intravenous infusion solutions.

 

Uses

Actions

Dopamine can stimulate alpha and beta adrenergic and dopamine receptors, and the type of receptor stimulated is determined by the dose.

At low doses (1 – 5 mcg/kg/min) stimulation of dopamine receptors predominates, the most important effects of which are renal and mesenteric vasodilation. There is an increase in glomerular filtration rate, renal blood flow, sodium excretion and urine output.

At intermediate infusion doses (5 – 20 mcg/kg/min), dopamine exerts a direct inotropic action on the myocardium causing dose-related increases in cardiac output with minimal effect on heart rate. Total peripheral resistance is relatively unchanged because of peripheral vasoconstriction (alpha adrenergic effect) and muscle vasodilation (beta adrenergic effect).

Blood pressure may rise and urinary output is further increased.

At 20 mcg/kg/min dopamine has a predominantly alpha adrenergic effect and there are further increases in cardiac output and total peripheral resistance; renal blood flow is maintained at levels higher than those obtained before therapy.

 

Indications

Dopamine is indicated for the correction of haemodynamic imbalance present in:

(a) Acute hypotension or shock associated with myocardial infarction, endotoxic septicaemia, trauma and renal failure.

(b) As an adjunct after open heart surgery, where there is persistent hypotension after correction of hypovolaemia.

(c) In chronic cardiac decompensation as in congestive failure.

 

Dosage and administration

Dopamine is a potent drug; it must be diluted before administration.

 

Adults

Where appropriate, the circulating blood volume must be restored with a suitable plasma expander or whole blood, prior to administration of dopamine hydrochloride.

Begin infusion of dopamine hydrochloride solution at doses of 2.5 mcg/kg/min in patients who are likely to respond to modest increments of heart force and renal perfusion. In more severe cases, administration may be initiated at a rate of 5 mcg/kg/min and increased gradually in 5 to 10 mcg/kg/min increments up to 20 to 50 mcg/kg/min as needed. If doses in excess of 50 mcg/kg/min are required, it is advisable to check urine output frequently.

Should urinary flow begin to decrease in the absence of hypotension, reduction of dopamine dosage should be considered. It has been found that more than 50 % of patients have been satisfactorily maintained on doses less than 20 mcg/kg/min.

In patients who do not respond to these doses, additional increments of dopamine may be given in an effort to achieve adequate blood pressure, urine flow and perfusion generally. Treatment of all patients requires constant evaluation of therapy in terms of blood volume, augmentation of cardiac contractility and distribution of peripheral perfusion and urinary output.

Dosage of dopamine should be adjusted according to the patient’s response, with particular attention to diminution of established urine flow rate, increasing tachycardia or development of new dysrhythmias as indications for decreasing or temporarily suspending the dosage.

 

Administration

DOPAMINE HYDROCHLORIDE INJECTION, after dilution, is administered intravenously through an intravenous catheter or needle in a vein as large as possible. An I.V. drip chamber or infusion pump is essential for controlling the infusion rate in drops/minute.

 

Preparation of infusion solutions

Suggested dilution: Aseptically transfer DOPAMINE HYDROCHLORIDE INJECTION into the I.V. solution as shown in the following table.

Strength Volume
ml
i.v. solution volume
ml
Final concentration microgram/ml
200 mg/5 ml 5 500 400
200 mg/5 ml 5 250 800
200 mg/5 ml 10 250 1600
200 mg/5 ml 20 500 1600

Dopamine hydrochloride can be diluted with

— 0.9 % Sodium Chloride Injection

— 5 % Dextrose, 0.45% Sodium Chloride Solution

— Compound Sodium Lactate (Hartmann’s) Solution

Dilution in these fluids retain at least 95 % of the original potency for 48 hours at room temperature under normal fluorescent light. Dilutions should be discarded immediately after use.

 

Children

The safety and efficacy of Dopamine in paediatric patients has not been established.

 

Geriatric

No variation in dosage is suggested for geriatric patients. However, close monitoring is suggested for blood pressure, urine flow and peripheral tissue perfusion.

 

Contra-indications, warnings, etc.

Dopamine should not be used in patients with phaeochromocytoma or hyperthyroidism.

Dopamine should not be used in the presence of uncorrected arterial or ventricular tachyarrhythmias or ventricular fibrillation.

Cyclopropane and halogenated hydrocarbon anaesthetics should be avoided.

 

Interactions

Anaesthetics: The myocardium is sensitised by the effect of Dopamine, Cyclopropane or halogenated hydrocarbon anaesthetics, and these should be avoided. This interaction applies both to pressor activity and cardiac beta adrenergic stimulation.

Alpha and beta blockers: The cardiac effects of Dopamine are antagonised by β-adrenergic blocking agents such as Propranolol and Metoprolol, and the peripheral vasoconstriction caused by high doses of Dopamine is antagonised by α-adrenergic blocking agents. Dopamine-induced renal and mesenteric vasodilation is not antagonised by either α- or β-adrenergic blocking agents, but, in animals, is antagonised by Haloperidol or other butyrophenones, phenothiazines, and opiates.

Monoamine oxidase (MAO): MAO inhibitors potentiate the effect of Dopamine and its duration of action. Patients who have been treated with monoamine oxidase (MAO) inhibitors prior to dopamine should be given reduced doses; the starting dose should be one tenth (1/10 th) of the usual dose.

Phenytoin: Administration of I.V. Phenytoin to patients receiving Dopamine has resulted in hypotension and bradycardia; some clinicians recommend that Phenytoin be used with extreme caution, if at all, in patients receiving Dopamine.

 

Use in pregnancy

Animal studies have shown no evidence of teratogenic effects with Dopamine. However, the effect of Dopamine on the human foetus is unknown therefore the drug should be used in pregnant women only when the expected benefits outweigh the potential risk to the foetus.

 

Use in lactation

It is not known if Dopamine is excreted in breast milk nor if there is any effect on the infant.

 

Warnings

Dopamine should not be used in the presence of uncorrected tachyarrhythmias or ventricular fibrillation. Nor it should be used in patients with phaeochromocytoma or hyperthyroidism. Cyclopropane and halogenated hydrocarbon anaesthetics should be avoided.

Patients who have been treated with MAO inhibitors prior to Dopamine should be given reduced doses; the starting dose should be one tenth (1/10 th) of the usual dose.

Excess administration of potassium-free solutions may result in significant hypokalaemia. The intravenous administration of these solutions can cause fluid and/or solute overloading resulting in dilution of serum electrolyte concentrations, overhydration, congested states or pulmonary oedema.

 

Precautions

Hypovolaemia should be corrected where necessary prior to Dopamine infusion. Low doses should be used in shock due to acute myocardial infarction. If a disproportionate rise in diastolic 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 an effect is desired.

Patients with a history of peripheral vascular disease should be closely monitored for any changes in colour or temperature of the skin of the extremities. If a change of skin colour or temperature occurs and is thought to be the result of compromised circulation to the extremities, the benefits of continued dopamine infusion should be weighed against the risk of possible necrosis. These changes may be reversed by decreasing the rate or discontinuing the infusion.

Dopamine hydrochloride in 5% dextrose injection should be infused into a large vein whenever possible to prevent the possibility of infiltration of perivascular tissue adjacent to the infusion site. Extravasation may cause necrosis and sloughing of the surrounding tissue. lschaemia can be reversed by infiltration of the affected area with 10-15 ml of saline containing 5 to 10mg phentolamine mesylate. A syringe with a fine hypodermic needle should be used to liberally infiltrate the ischaemic area as soon as extravasation is noted. Dopamine 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 overt diabetes mellitus.

 

Overdosage

Excessive elevation of blood pressure and vasoconstriction can occur due to the alpha adrenergic actions of dopamine, especially in patients with a history of occlusive vascular disease. If desired, this condition can be rapidly reversed by dose reduction or discontinuing the infusion, since dopamine has a half-life of less than 2 minutes in the body. Should these measures fail, an infusion of an alpha adrenergic blocking agent e.g., phentolamine mesylate should be considered. Dopamine at the infusion site can cause local vasoconstriction, hence the desirability of infusing into a large vein. The resulting ischaemia can be reversed by infiltration of the affected area with 10 -15 ml of saline containing 5 to 10 mg phentolamine mesylate. A syringe with a fine hypodermic needle should be used to liberally infiltrate the ischaemic area as soon as extravasation is noted.

 

Accidental overdosage

Accidental overdosage as evidenced by excessive blood pressure elevation can be controlled by dose reduction or discontinuing the dopamine infusion for a short period, since the duration of action of dopamine is short.

Should these measures fail, infusion of phentolamine mesylate should be considered.

 

Adverse reactions

Adverse reactions to dopamine are related to its pharmacological action.

 

More common reactions

Cardiovascular: Ectopic beats, tachycardia, anginal pain, palpitation, hypotension, vasoconstriction

Gastrointestinal: Nausea, vomiting.

Nervous System: Headache.

Respiratory: Dyspnoea.

 

Less common reactions

Biochemical Abnormalities: Azotaemia.

Cardiovascular: Aberrant conduction, bradycardia, widened QRS complex, hypertension, gangrene.

Nervous System: Piloerection

Serious or life-threatening reactions: Gangrene of feet has occurred following doses of 10 – 14 mcg/kg/min and higher in a few patients with pre-existing vascular disease.

 

Incompatibilities

DOPAMINE HYDROCHLORIDE INJECTION should not be added to any alkaline intravenous solutions, i.e. Sodium Bicarbonate. Any solution which exhibits physical or chemical incompatibility through a colour change or precipitate should not be administered. It is suggested that admixtures containing Gentamicin Sulphate, Cephalothin Sodium, Cephalothin Sodium Neutral or Oxacillin Sodium should be avoided unless all other viable alternatives have been exhausted.

Admixtures of Ampicillin and Dopamine in 5 % Glucose Solution are alkaline and incompatible and result in decomposition of both drugs. They should not be admixed.

Admixtures of Dopamine and Amphotericin B in 5% Glucose Solution are incompatible as a precipitate forms immediately on mixing.

 

Pharmaceutical precautions

Do not add Dopamine to 5% sodium bicarbonate or other alkaline solutions sin the drug inactivated.

Store below 30 °C, protect from light, do not use if discoloured. Any solution which exhibits physical or chemical incompatibility through a colour change or precipitate should not be administered.

Any portion of the contents remaining should be discarded.

 

Date of issue: January 1997

 

ROTEXMEDICA GmbH

BUNSENSTRASSE 4 • 22946 TRITTAU/GERMANY

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