DOPAMINE HCI

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 C8H11NO2 • HCl. The structural formula is: and the molecular weight is 189.64. Dopamine hydrochloride injection is a clear, practically colorless, sterile, pyrogen-free, aqueous solution of dopamine HCl for intravenous infusion after dilution. Each milliliter of the 40 mg/mL preparation contains 40 mg of dopamine hydrochloride (equivalent to 32.31 mg of dopamine base). Each milliliter of the 80 mg/mL preparation contains 80 mg of dopamine hydrochloride (equivalent to 64.62 mg of dopamine base). Each milliliter of both preparations contains the following: Sodium metabisulfite 9 mg added as an antioxidant; citric acid, anhydrous 10 mg; and sodium citrate, dihydrate 5 mg added as a buffer. May contain additional citric acid and/or sodium citrate for pH adjustment. pH is 3.3 (2.5 to 5.0). Dopamine must be diluted in an appropriate sterile parenteral solution before intravenous administration. ( See Dosage and Administration ) Structure

Dopamine HCl is indicated for the correction of hemodynamic imbalances present in the shock syndrome due to myocardial infarction, trauma, endotoxic septicemia, open-heart surgery, renal failure, and chronic cardiac decompensation as in congestive failure. Patients most likely to respond adequately to dopamine HCl are those in whom physiological parameters, such as urine flow, myocardial function, and blood pressure, have not undergone profound deterioration. Multiclinic trials indicate that the shorter the time interval between onset of signs and symptoms and initiation of therapy with blood volume correction and dopamine HCl, the better the prognosis. Where appropriate, blood volume restoration with a suitable plasma expander or whole blood should be accomplished prior to administration of dopamine HCl. 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 reversal of 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. Clinical studies have shown that when dopamine HCl 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 HCl has resulted in an increase in urine flow, which in some cases reached normal levels. Dopamine HCl may also increase urine flow in patients whose output is within normal limits and thus may be of value in reducing the degree of pre-existing fluid accumulation. It should be noted that at doses above those optimal for the individual patient, urine flow may decrease, necessitating reduction of dosage. Low Cardiac Output – Increased cardiac output is related to dopamine'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 movements 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 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 HCl which have little effect on SVR. At high therapeutic doses, dopamine'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 HCl as soon as a definite trend toward decreased systolic and diastolic pressure becomes evident.

WARNING: This is a potent drug; it must be diluted before administration to the patient. Dopamine Hydrochloride Injection, USP is administered (only after dilution) by intravenous infusion. Suggested Dilution – For the 40 mg/mL preparation, transfer by aseptic technique the contents containing either 5 mL, 200 mg or 10 mL, 400 mg of Dopamine Hydrochloride to either a 250 mL or 500 mL bottle of one of the sterile intravenous solutions listed below. For the 80 mg/mL preparation, transfer by aseptic technique the contents containing 10 mL, 800 mg of Dopamine Hydrochloride to a 250 mL, 500 mL or 1000 mL bottle of one of the following sterile intravenous solutions: 0.9% Sodium Chloride Injection, USP 5% Dextrose Injection, USP 5% Dextrose and 0.9% Sodium Chloride Injection, USP 5% Dextrose and 0.45% Sodium Chloride Injection, USP 5% Dextrose and Lactated Ringer's Injection Sodium Lactate Injection, USP 1/6 Molar Lactated Ringer's Injection, USP The resultant dilutions are summarized in the following chart: Dopamine Hydrochloride Injection, USP has been found to be stable for a minimum of 24 hours after dilution in the foregoing intravenous solutions. However, as with all intravenous admixtures, dilution should be made just prior to administration. Do NOT add Dopamine Hydrochloride to Sodium Bicarbonate Injection, USP or other alkaline intravenous solutions, since the drug is inactivated in alkaline solution. Rate of Administration – Dopamine Hydrochloride Injection, USP after dilution, is administered intravenously by infusion via a suitable intravenous catheter or needle. When administering Dopamine Hydrochloride (or any potent medication) by continuous intravenous infusion, it is advisable to use a precision volume control intravenous set. Each patient must be individually titrated to the desired hemodynamic or renal response to dopamine. 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 at rates greater than 50 mcg/kg/min 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. Suggested Regimen: 1. When appropriate, increase blood volume with whole blood or plasma until central venous pressure is 10 to 15 cm H 2O or pulmonary wedge pressure is 14 to 18 mm Hg. 2. Begin infusion of diluted solution at doses of 2 – 5 mcg/kg/min of Dopamine Hydrochloride in patients who are likely to respond to modest increments of heart force and renal perfusion. In more seriously ill patients, begin infusion of diluted solution at doses of 5 mcg/kg/min of Dopamine Hydrochloride 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 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. Multiclinic trials have shown that more than 50 percent of patients have been satisfactorily maintained on doses 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 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 cardiac contractility, and distribution of peripheral perfusion. 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 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 to avoid inadvertent administration of a bolus of the drug. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. Dilution Table

Dopamine HCl should not be used in patients with pheochromocytoma. Dopamine HCl should not be administered to patients with uncorrected tachyarrhythmias or ventricular fibrillation.

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.