Dopamine (medication)

Dopamine is a naturally occurring neurotransmitter that also functions as a medication. As a drug, dopamine is primarily used in the treatment of low blood pressure, low heart rate, and cardiac arrest. It is also used in the treatment of severe hypotension, particularly when associated with shock states such as cardiogenic shock or septic shock.

Dopamine functions as an inotrope, increasing myocardial contractility (the force of heart muscle contraction) and thereby increasing cardiac output. Its effects are dose-dependent. At low doses (0.5-2 micrograms/kg/min), it mainly stimulates dopamine receptors, resulting in renal vasodilation and increased urine output (although the clinical significance of this is debated). At moderate doses (2-10 micrograms/kg/min), it stimulates beta-1 adrenergic receptors, leading to increased heart rate and contractility. At high doses (above 10 micrograms/kg/min), it stimulates alpha-1 adrenergic receptors, causing vasoconstriction and increasing blood pressure.

Dopamine is administered intravenously, as it is rapidly metabolized if given orally. The dosage is carefully titrated based on the patient's response and blood pressure. Vital signs, including blood pressure, heart rate, and urine output, are closely monitored during dopamine infusion.

Common side effects of dopamine include nausea, vomiting, headache, and arrhythmias (irregular heartbeats). More serious side effects can include excessive vasoconstriction, which can lead to tissue ischemia or necrosis, and pulmonary edema. Dopamine should be used with caution in patients with pre-existing arrhythmias or underlying cardiovascular disease. It is also contraindicated in patients with pheochromocytoma (a tumor of the adrenal gland).

Dopamine is a potent medication that requires careful monitoring and titration. It is typically administered in an intensive care setting by healthcare professionals experienced in its use.