Dopamine

(doe pah meen)

PCaution when used during lactation - Caution when used during pregnancy

Molecule Info

 | See TERMINOLOGY & ABBREVIATIONS |
Description

Dopamine Hydrochloride and 5% Dextrose Injection, USP is a sterile, nonpyrogenic, prediluted solution of dopamine hydrochloride in 5% dextrose injection. It is administered by intravenous infusion.

Dopamine, a sympathomimetic amine vasopressor, is the naturally occurring immediate precursor of norepinephrine. Dopamine hydrochloride is a white to off-white, crystalline powder, which may have a slight odor of hydrochloric acid. It is freely soluble in water and soluble in alcohol. Dopamine HCl is sensitive to alkalies, iron salts, and oxidizing agents. Chemically it is designated as 4-(2-aminoethyl)pyrocatechol hydrochloride, and its molecular formula is C8H11NO- HCl (mol. wt. 189.64). 

Dopamine hydrochloride injection is a clear, practically colorless, sterile, pyrogen-free, aqueous solution of dopamine HCl for intravenous infusion after dilution.

Dextrose, USP is chemically designated D-glucose monohydrate (C6H12O6 â€¢ H2O) mol. wt. 198.17, a hexose sugar freely soluble in water. 

Water for Injection, USP is chemically designated H2O.

Each 100 mL contains dopamine hydrochloride 80 mg (equivalent to 64.6 mg dopamine base), 160 mg (equivalent to 129.2 mg dopamine base) or 320 mg (equivalent to 258.4 mg dopamine base) and dextrose, hydrous 5 g in water for injection, with sodium metabisulfite 50 mg added as an antioxidant; osmolar concentration, respectively 269, 277 or 294 mOsmol/liter (calc.). pH 3.6 (2.5 to 4.5). May contain hydrochloric acid and/or sodium hydroxide for pH adjustment. Dopamine Hydrochloride and 5% Dextrose Injection, USP is oxygen sensitive. The solution contains no bacteriostat, antimicrobial agent or added buffer (except for pH adjustment), and is intended only for use as a single-dose injection. When smaller doses are required the unused portion should be discarded.

Indication(s) & Dosage

Intravenous Acute heart failure  Adult: As hydrochloride: Initially, 1-5 mcg/kg/min increased gradually by up to 5-10 mcg/kg/min according to the patient's BP, cardiac output and urine output.  Up to 20-50 mcg/kg/min may be required in seriously ill patients.

Overdose

Symptoms include excessive BP elevation.  Treatment includes reducing rate of admin or temporarily discontinuing therapy until patient's condition stabilises.  Usually, no additional remedial measures are needed as dopamine has short duration of action.  In severe cases, short-acting alpha-adrenergic blocking agent, phentolamine, may be used.

Contraindications

Pheochromocytoma, uncorrected tachyarrhythmias, ventricular fibrillation.  Hypersensitivity.

Special Precautions

Shock secondary to MI, history of peripheral vascular disease.  Correct hypovolaemia before infusion.  History of occlusive vascular disease e. g, atherosclerosis, Raynaud's disease, Buerger's disease, diabetic endarteritis; disproportionate increase in diastolic pressure.  Pregnancy.

Adverse Drug Reaction(s)

Nausea, vomiting, tachycardia, ectopic beats, palpitation, anginal pain, hypotension, vasoconstriction, bradycardia, hypertension, dyspnoea, headache, widened QRS complexes, azotaemia.

Drug Interactions

Cyclopropane and halogenated hydrocarbon anaesthetics may sensitise myocardium to dopamine and precipitate ventricular arrhythmias.  MAO inhibitors prolong and increase dopamine effects.  Ergots potentiate vasoconstriction action of dopamine.  Alpha-blockers unmask dopamine's beta action.

Lab Interference

Suppresses pituitary secretion of thyroid-stimulating hormone, growth hormone and prolactin.

Pregnancy Category (FDA) 

Category C: Either studies in animals have revealed adverse effects on the foetus and there are no controlled studies in women or studies in women and animals are not available.  Drugs should be given only if the potential benefit justifies the potential risk to the foetus.

Storage

Intravenous: Store below 30°C.

Pharmacology

CLINICAL PHARMACOLOGY

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.

Dopamine’s onset of action occurs within five minutes of intravenous administration, and with dopamine’s plasma half-life of about two minutes, the duration of action is less than ten minutes. However, if monoamine oxidase (MAO) inhibitors are present, the duration may increase to one hour. The drug is widely distributed in the body but does not cross the blood-brain barrier to a significant extent. Dopamine is metabolized in the liver, kidney, and plasma by MAO and catechol-O-methyltransferase to the inactive compounds homovanillic acid (HVA) and 3,4-dihydroxyphenylacetic acid. About 25% of the dose is taken up into specialized neurosecretory vesicles (the adrenergic nerve terminals), where it is hydroxylated to form norepinephrine. 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.

The predominant effects of dopamine are dose-related, although it should be noted that actual response of an individual patient will largely depend on the clinical status of the patient at the time the drug is administered. At low rates of infusion (0.5-2 mcg/kg/min) dopamine causes vasodilation that is presumed to be due to a specific agonist action on dopamine receptors (distinct from alpha- and beta-adrenoceptors) in the renal, mesenteric, coronary, and intracerebral vascular beds. At these dopamine receptors, haloperidol is an antagonist. The vasodilation in these vascular beds is accompanied by increased glomerular filtration rate, renal blood flow, sodium excretion, and urine flow. Hypotension sometimes occurs. An increase in urinary output produced by dopamine is usually not associated with a decrease in osmolality of the urine.

At intermediate rates of infusion (2-10 mcg/kg/min) dopamine acts to stimulate the beta1-adrenoceptors, resulting in improved myocardial contractility, increased SA rate and enhanced impulse conduction in the heart. There is little, if any, stimulation of the beta2-adrenoceptors (peripheral vasodilation). Dopamine causes less increase in myocardial oxygen consumption than isoproterenol, and its use is not usually associated with a tachyarrhythmia. Clinical studies indicate that it usually increases systolic and pulse pressure with either no effect or a slight increase in diastolic pressure. Blood flow to the peripheral vascular beds may decrease while mesenteric flow increases due to increased cardiac output. Total peripheral resistance (alpha effects) at low and intermediate doses is usually unchanged.

At higher rates of infusion (10-20 mcg/kg/min) there is some effect on alpha-adrenoceptors, with consequent vasoconstrictor effects and a rise in blood pressure. The vasoconstrictor effects are first seen in the skeletal muscle vascular beds, but with increasing doses, they are also evident in the renal and mesenteric vessels. At very high rates of infusion (above 20 mcg/kg/min), stimulation of alpha-adrenoceptors predominates and vasoconstriction may compromise the circulation of the limbs and override the dopaminergic effects of dopamine, reversing renal dilation and naturesis.

Solutions containing carbohydrate in the form of dextrose restore blood glucose levels and provide calories. Carbohydrate in the form of dextrose may aid in minimizing liver glycogen depletion and exerts a protein-sparing action. Dextrose injected parenterally undergoes oxidation to carbon dioxide and water.

Water is an essential constituent of all body tissues and accounts for approximately 70% of total body weight. Average normal adult daily requirement ranges from two to three liters (1.0 - 1.5 liters each for insensible water loss due to perspiration and urine production).

Water balance is maintained by various regulatory mechanisms. Water distribution depends primarily on the concentration of electrolytes and sodium (Na+) plays a major role in maintaining physiologic equilibrium.

ATC Classification

C01CA04 - dopamine; Belongs to the class of adrenergic and dopaminergic cardiac stimulants excluding glycosides.  Used in the treatment of heart failure.

 

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Brand/Product Info


Total Products : 4    
Brand Name Manufacturer/Marketer Composition Dosage Form Pack Size & Price
CARDOPA ACI Ltd. Dopamine 200mg/5ml IV Injection 5's: 225.85 MRP
D-DOPAMINE Drug International Ltd Dopamine 200mg/5ml IV Injection 3's: 135 MRP
DOPAMINE-ROTEX Rotex/City Overseas Dopamine 200mg/5ml IV Injection 10's: 600.00 TP
Myomine Incepta Pharmaceuticals Limited Dopamine Hydrochloride 200 mg/5 ml Injection Injection 1x5's:MRP 225 Tk