Dopamine, 5mg/ml, 5 ml, 10 pcs.

Dopamine is an adrenomimetic, hypertensive.

It excites beta-adrenoreceptors (in small and medium doses) and alpha-adrenoreceptors (in large doses). Improvement of systemic hemodynamics leads to a diuretic effect. It has a stimulating effect on dopamine receptors. At low doses (0.5-3 µg/kg/min) it acts mainly on dopaminergic receptors. Due to the specific effect on peripheral dopamine receptors, it reduces renal vascular resistance, increases blood flow in them, glomerular filtration, sodium excretion and diuresis.

Dilates mesenteric vessels (this distinguishes dopamine from other catecholamines in its action on renal and mesenteric vessels). At low to medium doses (2-10 µg/kg/min), it stimulates beta₁ adrenoreceptors, which causes a positive inotropic effect on the myocardium and an increase in cardiac minute volume. Systolic BP and pulse pressure may increase, with dAP unchanged or slightly increased. OPSS usually does not change. Coronary blood flow and myocardial oxygen consumption, increase.

At high doses (10 µg/kg/min or more), alpha₁-adrenoreceptor stimulation prevails, and OPPS increases and renal vessels narrow (the latter may reduce previously increased renal blood flow and diuresis). Both cAD and dAP increase due to increased cardiac minute volume and peripheral resistance. After discontinuation of administration, the effect lasts for 5-10 min.

Pharmacokinetics

After IV administration, T_1/2 is less than 5 min. It is metabolized in the liver, kidneys and plasma to form inactive metabolites; 85% of the administered dose is excreted in the urine within 24 hours.

About 25% of the dose is taken up by neurosecretory vesicles, where hydroxylation occurs and norepinephrine is formed. Binds to plasma proteins 50%, is rapidly metabolized in the liver, kidneys and plasma by MAOA and catechol-O-methyltransferase (COMT) to inactive metabolites.T_1/2 – adults: from plasma – 2 min, tissue – 9 min; newborns – 6.9 min (range 5-11 min). Excreted by the kidneys; 80% of the dose is as metabolites within 24 h.

Indications

Shock of different genesis (cardiogenic, postoperative, infectious-toxic, anaphylactic, hypovolemic (only after the restoration of the blood circulation); acute cardiac and vascular insufficiency in various severe pathological states.

Active ingredient

Dopamine

Composition

Active ingredient:

dopamine hydrochloride;

Associates:

L-cysteine hydrochloride hydrate;

citric acid monohydrate;

Sodium hydroxide;

Sodium chloride;

Injectable water

How to take, the dosage

Intravenously by infusion. The dose is selected individually and depends on the severity of the shock, as well as the patient’s response to treatment. Unless otherwise prescribed, the following doses are recommended:

(a) the low-dose region (for intensive treatment in the internal medicine clinic) is 100-250 mcg/min = 1.5-3.5 mcg/kg/min,

b) the area of medium doses (for intensive treatment in the surgical clinic) – 300-700 mcg/min = 4-10 mcg/kg/min,

c) the area of maximum doses (in septic shock) – 750-1500 mcg/min = 10.5-21.5 mcg/kg/min .

The rate of administration should be chosen individually to achieve an optimal patient response. Most patients are able to maintain a satisfactory response with dopamine doses less than 20 µg/kg/min.

To increase myocardial contractile activity (positive inotropic effect), the recommended dose is 100-250 mcg/min.

The maximum increase in diuresis is achieved at 250 mcg/min (increasing the rate of administration up to 1200 mcg/min does not change diuresis). When further increasing the dose, a possible decrease in diuresis should be taken into account.

In order to influence BP, it is recommended to increase the dose to 500 mcg/min or more, or if the dopamine dose is constant, norepinephrine (noradrenaline) is additionally administered in a dose of 5 mcg/min at a patient weight of about 70 kg. If cardiac rhythm disturbances occur, regardless of the doses used, further dose increases are contraindicated.

In children, 4 mcg/kg/min, the maximum dose is 6 mcg/kg/min. In contrast to adults, in children the dose should be increased gradually, i.e., starting with the lowest dose.

Duration of use: the duration of infusions depends on the individual characteristics of the patient. There is positive experience with infusions lasting up to 28 days. After stabilization of clinical situation the drug shall be withdrawn gradually. The solution for infusion should be prepared anew each time before use. Transparent infusion solutions, which do not stain when adding the drug, should be used.

The ready-to-use infusion solutions remain stable for the normal infusion period (at least 24 hours), except when mixed with Ringer-lactate solution (max. 6 hours).

Recommended dilution solutions: – 0.9% sodium chloride solution, 5.0% glucose solution, Ringer-lactate solution.

Interaction

Because of the risk of arrhythmias, caution should be exercised when prescribing dopamine in patients in whom cyclopropane or halogenated hydrocarbons are used for inhaled general anesthesia.

The combination of dopamine and ergot alkaloids may result in maximal peripheral vasoconstriction with a risk of gangrene. Patients who receive or have received monoamine oxidase inhibitors within the last 2 weeks should be prescribed a significantly lower dose of dopamine (the starting dose should be 1/10 of the usual dose).

The concomitant use with phenytoin or tricyclic antidepressants may cause BP lowering and bradycardia. Concomitant administration of dopamine and diuretics may be accompanied by additive and potentiating effects. Beta-adrenoblockers (propranolol and metoprolol) are antagonists of cardiac effect of dopamine.

Concomitant administration with guanethidine increases the sympathomimetic effect, with dobutamine there may be a more pronounced increase in BP (but ventricular pressure during diastole decreases or remains the same).

Special Instructions

In case of increased myocardial pre- and post-loading, a combination with nitroglycerin or sodium nitroprusside is recommended to relieve the heart.

Contraindications

Hypersensitivity to the components of the drug (including other sympathomimetics), hyperthyroidism, pheochromocytoma, closed-angle glaucoma, prostatic hyperplasia with clinical manifestations, tachyarrhythmias, ventricular fibrillation.

Side effects

Nausea, vomiting, headache, anxiety, agitation, hand tremors, angina pectoris, palpitations, increased BP, in rare cases myocardial ischemia may occur.

The administration of dopamine may cause arrhythmias (sinus tachycardia, supraventricular and ventricular arrhythmias) and an undesirable increase in left ventricular end-diastolic pressure.

In some cases, cardiac conduction abnormalities, bradycardia, dilated QRS complex, BP lowering (increasing the infusion rate is usually sufficient to eliminate these effects), azotemia and piloerection have been observed. In some cases polyuria is observed during infusion (diuresis should be controlled).

In extremely rare cases, dopamine administration may cause skin necrosis or gangrene. Inadvertent paravenous administration may cause soft tissue necrosis.

Overdose

Symptoms: excessive rise in BP, arrhythmia.

Treatment: reduce the dose or stop IV administration for some time, because dopamine has a short-term effect. In severe cases, alpha- or beta-adrenoblockers should be considered.

Similarities

Dopamine, Dopamine