DOPamine Hydrochloride

INDICATIONS AND USAGE Dopamine hydrochloride is indicated for the correction of hemodynamic imbalances present in the shock syndrome due to myocardial infarctions, trauma, endotoxic septicemia, open heart surgery, renal failure and chronic cardiac decompensation as in congestive failure. Where appropriate, restoration of blood volume with a suitable plasma expander or whole blood should be instituted or completed prior to administration of dopamine hydrochloride. Patients most likely to respond adequately to dopamine hydrochloride are those in whom physiological parameters, such as urine flow, myocardial function and blood pressure have not undergone profound deterioration. Reports indicate that the shorter the time interval between onset of signs and symptoms and initiation of therapy with volume correction and dopamine hydrochloride, the better the prognosis. Poor Perfusion of Vital Organs Urine flow appears to be one of the better diagnostic signs by which adequacy of vital organ perfusion can be monitored. Nevertheless, the physician should also observe the patient for signs of reversal of confusion or comatose condition. Loss of pallor, increase in toe temperature and/or adequacy of nail bed capillary filling may also be used as indices of adequate dosage. Reported studies indicate that when dopamine hydrochloride is administered before urine flow has diminished to levels of approximately 0.3 mL/minute, prognosis is more favorable. Nevertheless, in a number of oliguric or anuric patients, administration of dopamine hydrochloride has resulted in an increase in urine flow which in some cases reached normal levels. Dopamine hydrochloride may also increase urine flow in patients whose output is within normal limits and thus may be of value in reducing the degree of preexisting fluid accumulation. It should be noted that at doses above those optimal for the individual patient, urine flow may decrease, necessitating reduction of dosage. Concurrent administration of dopamine hydrochloride and diuretic agents may produce an additive or potentiating effect. Low Cardiac Output Increased cardiac output is related to dopamine hydrochloride’s direct inotropic effect on the myocardium. Increased cardiac output at low or moderate doses appears to be related to a favorable prognosis. Increase in cardiac output has been associated with either static or decreased systemic vascular resistance (SVR). Static or decreased SVR associated with low or moderate increments in cardiac output is believed to be a reflection of differential effects on specific vascular beds with increased resistance in peripheral beds (e.g., femoral) and concomitant decreases in mesenteric and renal vascular beds. Redistribution of blood flow parallels these changes so that an increase in cardiac output is accompanied by an increase in mesenteric and renal blood flow. In many instances the renal fraction of the total cardiac output has been found to increase. Increase in cardiac output produced by dopamine hydrochloride is not associated with substantial decreases in systemic vascular resistance as may occur with isoproterenol. Hypotension Hypotension due to inadequate cardiac output can be managed by administration of low to moderate doses of dopamine hydrochloride, which have little effect on SVR. At high therapeutic doses, dopamine hydrochloride’s alpha-adrenergic activity becomes more prominent and thus may correct hypotension due to diminished SVR. As in the case of other circulatory decompensation states, prognosis is better in patients whose blood pressure and urine flow have not undergone profound deterioration. Therefore, it is suggested that the physician administer dopamine hydrochloride as soon as a definite trend toward decreased systolic and diastolic pressure becomes evident.

DOSAGE AND ADMINISTRATION Rate of Administration Dopamine Hydrochloride and 5% Dextrose Injection, USP is administered intravenously through a suitable intravenous catheter or needle. An IV drip chamber or other suitable metering device is essential for controlling the rate of flow in drops/minute. Each patient must be individually titrated to the desired hemodynamic 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 hemodynamic condition is stabilized. Administration of dopamine hydrochloride at rates greater than 50 mcg/kg/min has safely been used in advanced circulatory decompensation states. If unnecessary fluid expansion is of concern, use of a more concentrated solution may be preferred over increasing the flow rate of a less concentrated solution. Suggested Regimen 1. When appropriate, increase blood volume with whole blood, plasma, or plasma expanders until central venous pressure is 10 to 15 cm H2O or pulmonary wedge pressure is 14 to 18 mm Hg. 2. Begin infusion of Dopamine Hydrochloride and 5% Dextrose Injection, USP at doses of 2 to 5 mcg/kg/min in patients who are likely to respond to modest increments of heart force and renal perfusion. In more seriously ill patients, begin administration of Dopamine Hydrochloride and 5% Dextrose Injection, USP at rates of 5 mcg/kg/min and increase gradually using 5 to 10 mcg/kg/min increments up to a rate of 20 to 50 mcg/kg/min as needed. If rates in excess of 50 mcg/kg/min are required, it is suggested that urine output be checked frequently. Should urine flow begin to decrease in the absence of hypotension, reduction of dopamine hydrochloride dosage should be considered. Reports have shown that more than 50% of the patients were satisfactorily maintained on doses of dopamine hydrochloride administered at rates of less than 20 mcg/kg/min. In patients who do not respond to these doses with adequate arterial pressures or urine flow, additional increments of dopamine hydrochloride may be given in an effort to produce an appropriate arterial pressure and central perfusion. 3. Treatment of all patients requires constant evaluation of therapy in terms of blood volume, augmentation of myocardial contractility and distribution of peripheral perfusion. Dosage of dopamine hydrochloride 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 indices for decreasing or temporarily suspending the dosage. 4. As with all potent intravenously administered drugs, care should be taken to control the rate of administration so as to avoid inadvertent administration of a bolus of drug. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. Do not use Dopamine Hydrochloride and 5% Dextrose Injection, USP if darker than slightly yellow or discolored in any other way. All injections in VIAFLEX Plus plastic containers are intended for intravenous administration using sterile equipment. Drug additives should not be made to Dopamine Hydrochloride and 5% Dextrose Injection, USP. Pediatric Dosing and Administration In publications, the most common starting doses were 1-5 micrograms/kilograms/minute. Particularly in neonates, such low doses require considerable dilution of this product; careful consideration should be given to the use of this product in such circumstances. Dosing increments that were reported ranged from 2.5 to 5.0 micrograms/kilogram/minute. Usual maximum doses were 15-20 micrograms/kilogram/minute, with occasional use as great as 50 micrograms/kilogram/minute. The time course of dopamine kinetics is poorly defined. Increasing infusion rates (or dose) should be approached cautiously and only after it is apparent that hemodynamics (mainly systolic blood pressure) have stabilized with respect to the current dose and/or rate of infusion. There have been occasional reports of vasospastic events when dopamine was infused through umbilical vessels. Due caution should be exercised if infusion of dopamine through umbilical vessels becomes necessary.

CONTRAINDICATIONS Dopamine hydrochloride should not be used in patients with pheochromocytoma. Dopamine hydrochloride should not be administered in the presence of uncorrected tachyarrhythmias or ventricular fibrillation. Solutions containing dextrose may be contraindicated in patients with known allergy to corn or corn products.

WARNINGS Patients who have been treated with monoamine oxidase (MAO) inhibitors prior to the administration of dopamine hydrochloride will require substantially reduced dosage. See Drug Interactions , below. Evidence is inadequate for fully defining proper dosage and limitations for use in children. Contains sodium bisulfite, a sulfite that may cause allergic-type reactions including anaphylactic symptoms and life-threatening or less severe asthmatic episodes in certain susceptible people. The overall prevalence of sulfite sensitivity in the general population is unknown and probably low. Sulfite sensitivity is seen more frequently in asthmatic than in nonasthmatic people. Do not add Dopamine Hydrochloride and 5% Dextrose Injection, USP to any alkaline diluent solution since dopamine hydrochloride is inactivated in alkaline solution. Solutions containing dextrose should not be administered through the same administration set as blood, as this may result in pseudoagglutination or hemolysis. The intravenous administration of solutions may cause fluid overloading resulting in dilution of serum electrolyte concentrations, overhydration, congested states or pulmonary edema. Excess administration of potassium-free solutions may result in significant hypokalemia.

Drug Interactions Cyclopropane or halogenated hydrocarbon anesthetics increase cardiac autonomic irritability and may sensitize the myocardium to the action of certain intravenously administered catecholamines, such as dopamine. This interaction appears to be related both to pressor activity and to the beta-adrenergic stimulating properties of these catecholamines, and may produce ventricular arrhythmias. Therefore, EXTREME CAUTION should be exercised when administering dopamine HCl to patients receiving cyclopropane or halogenated hydrocarbon anesthetics. Results of studies in animals indicate that dopamine-induced ventricular arrhythmias during anesthesia can be reversed by propranolol. Because dopamine is metabolized by monoamine oxidase (MAO), inhibition of this enzyme prolongs and potentiates the effect of dopamine. Patients who have been treated with MAO inhibitors within two to three weeks prior to the administration of dopamine should receive initial doses of dopamine hydrochloride no greater than one-tenth (1/10) of the usual dose. Concurrent administration of low-dose dopamine HCl and diuretic agents may produce an additive or potentiating effect on urine flow. Tricyclic antidepressants may potentiate the cardiovascular effects of adrenergic agents. Cardiac effects of dopamine are antagonized by beta-adrenergic blocking agents, such as propranolol and metoprolol. The peripheral vasoconstriction caused by high doses of dopamine HCl is antagonized by alpha-adrenergic blocking agents. Dopamine-induced renal and mesenteric vasodilation is not antagonized by either alpha- or beta-adrenergic blocking agents. Butyrophenones (such as haloperidol) and phenothiazines can suppress the dopaminergic renal and mesenteric vasodilation induced with low-dose dopamine infusion. The concomitant use of vasopressors, vasoconstrictor agents (such as ergonovine) and some oxytocic drugs may result in severe hypertension. Administration of phenytoin to patients receiving dopamine HCl has been reported to lead to hypotension and bradycardia. It is suggested that in patients receiving dopamine HCl, alternatives to phenytoin should be considered if anticonvulsant therapy is needed.

ADVERSE REACTIONS The following adverse reactions have been observed, but there are not enough data to support an estimate of their frequency. Cardiovascular System ventricular arrhythmia atrial fibrillation ectopic beats tachycardia anginal pain palpitation cardiac conduction abnormalities widened QRS complex bradycardia hypotension hypertension vasoconstriction Respiratory System dyspnea Gastrointestinal System nausea vomiting Metabolic/Nutritional System azotemia Central Nervous System headache anxiety Dermatological System piloerection Other Gangrene of the extremities has occurred when high doses were administered for prolonged periods or in patients with occlusive vascular disease receiving low doses of dopamine HCl.

Pregnancy Teratogenic Effects Teratogenicity studies in rats and rabbits at dopamine HCl dosages up to 6 mg/kg/day intravenously during organogenesis produced no detectable teratogenic or embryotoxic effects, although maternal toxicity consisting of mortalities, decreased body weight gain, and pharmacotoxic signs were observed in rats. In a published study, dopamine HCl administered at 10 mg/kg subcutaneously for 30 days, markedly prolonged metestrus and increased mean pituitary and ovary weights in female rats. Similar administration to pregnant rats throughout gestation or for 5 days starting on gestation day 10 or 15 resulted in decreased body weight gains, increased mortalities and slight increases in cataract formation among the offspring. There are no adequate and well-controlled studies in pregnant women, and it is not known if dopamine HCl crosses the placental barrier. Dopamine HCl should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.