Dopamine

Mechanism :

Dopamine is a natural catecholamine formed by the decarboxylation of 3,4-dihydroxyphenylalanine (DOPA). It is a precursor to norepinephrine 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.

Indication :

• Hypotension
• Shock
• Septicemia

Contraindications :

Dopamine should not be used in patients with pheochromocytoma, in patients with uncorrected tachyarrhythmias or ventricular fibrillation.

Dosing :

Adverse Effect :

Tachycardia, ectopic beats, anginal pain, vasoconstriction, palpitation, nausea, hypotension, vomiting, headache, dyspnea, aberrant conduction, bradycardia, widened QRS complex, hypertension and gangrene.

Interaction :

MAO inhibitors: Inhibition of this enzyme prolongs and potentiates the effect of dopamine.
Diuretic agents: May produce an additive or potentiating effect on urine flow.
Tricyclic Antidepressants: May potentiate the cardiovascular effects of adrenergic agents
Beta-adrenergic Blocking Agents: Cardiac effects of dopamine are antagonized by beta-adrenergic blocking agents.
Cyclopropane or Halogenated Hydrocarbon Anesthetics: Increase cardiac autonomic irritability and may sensitize the myocardium to the action of dopamine and may produce ventricular arrhythmias and hypertension.
Vasopressors, Vasoconstricting Agents: May result in severe hypertension.
Phenytoin: Lead to hypotension and bradycardia.

Renal Dose :

Hepatic Dose :