Myomine

Approved Indications:

• Cardiogenic shock: To improve cardiac output by increasing myocardial contractility and heart rate.
• Hypotension: Treatment of symptomatic hypotension due to low cardiac output or shock states.
• Septic shock: Adjunct to restore blood pressure and improve perfusion.
• Heart failure: Short-term treatment of decompensated heart failure with reduced cardiac output.
• Renal perfusion support: Historically used to improve renal blood flow and urine output in oliguric states (though this use is controversial and less supported).

Off-label / Clinically Accepted Uses:

• Support of blood pressure in distributive or vasodilatory shock when fluids alone are insufficient.
• Adjunctive treatment in trauma or post-operative hypotension.
• Occasionally for bradycardia refractory to atropine.

Route: Intravenous infusion only (continuous infusion).

Adults:

• Low dose (dopaminergic effect): 1–5 mcg/kg/min — primarily renal and mesenteric vasodilation.
• Intermediate dose (beta-1 adrenergic effect): 5–10 mcg/kg/min — increased myocardial contractility and heart rate.
• High dose (alpha-adrenergic effect): >10 mcg/kg/min — vasoconstriction increasing systemic vascular resistance and blood pressure.

Pediatrics:

• Initial dose 1–5 mcg/kg/min; titrate based on clinical response and hemodynamics.

Elderly:

• Start at lower doses; titrate cautiously due to increased cardiovascular sensitivity.

Renal/Hepatic Impairment:

• No specific dose adjustment recommended; monitor response closely.

Administration Notes:

• Diluted in compatible IV fluids, administered by controlled infusion pump.
• Continuous cardiac monitoring and frequent blood pressure checks are mandatory.
• Infusion rate adjusted according to clinical response and side effects.
• Do not use as a bolus or push injection.

Dopamine is an endogenous catecholamine and a precursor of norepinephrine with dose-dependent receptor activity. At low doses, it stimulates dopamine-1 (D1) receptors causing vasodilation of renal, mesenteric, coronary, and cerebral vessels. At intermediate doses, it activates β1-adrenergic receptors, enhancing myocardial contractility and heart rate (positive inotropy and chronotropy), improving cardiac output. At high doses, it stimulates α1-adrenergic receptors, causing vasoconstriction, increasing systemic vascular resistance and blood pressure. These combined effects improve tissue perfusion and hemodynamics in shock states.

• Absorption: Administered intravenously; immediate onset (within 1–2 minutes).
• Distribution: Rapid distribution with a volume of distribution around 2.6 L/kg.
• Metabolism: Rapidly metabolized by monoamine oxidase (MAO) and catechol-O-methyltransferase (COMT) in liver, kidney, and plasma.
• Half-life: Very short, approximately 2 minutes.
• Elimination: Metabolites excreted primarily in urine.

• Pregnancy: FDA Category C
• Animal studies show no direct teratogenic effects; insufficient well-controlled human studies.
• Use only if benefits outweigh risks.
• Lactation:
• Unknown if excreted in human milk.
• Caution advised; use only if clearly needed.

• Primary Class: Vasopressor / Inotropic agent
• Subclass: Sympathomimetic catecholamine

• Known hypersensitivity to dopamine or excipients.
• Uncorrected tachyarrhythmias or ventricular fibrillation.
• Pheochromocytoma (risk of hypertensive crisis).
• Use cautiously or avoid in patients with hypovolemia without adequate fluid resuscitation.

• Use under continuous cardiac and hemodynamic monitoring.
• Risk of tachyarrhythmias and myocardial ischemia due to increased oxygen demand.
• Excessive vasoconstriction may compromise peripheral and splanchnic perfusion.
• Extravasation may cause severe local tissue necrosis; administer via central line if possible.
• Monitor for hypokalemia, which may be aggravated by dopamine.
• Adjust or discontinue in case of arrhythmias or hypertension.
• Use caution in patients with preexisting cardiovascular disease.

Common:

• Tachycardia, palpitations
• Hypertension or hypotension (dose-dependent)
• Headache
• Nausea, vomiting

Less common:

• Arrhythmias (ventricular and supraventricular)
• Anxiety, nervousness
• Dyspnea

Rare / Serious:

• Myocardial ischemia or infarction
• Extravasation injury leading to tissue necrosis
• Hypertensive crisis
• Hyperglycemia (due to β2 receptor stimulation)

• MAO inhibitors: May potentiate and prolong dopamine effects; contraindicated.
• Beta-blockers: May antagonize beta effects, unmasking alpha effects, causing hypertension and vasoconstriction.
• Tricyclic antidepressants: Potentially enhanced vasopressor effects.
• Phenytoin: May decrease dopamine efficacy.
• General anesthetics: Additive cardiovascular effects, increased arrhythmia risk.

• Current critical care guidelines recommend dopamine primarily for select shock states with low cardiac output and hypotension after adequate fluid resuscitation.
• Evidence supports norepinephrine as preferred vasopressor in septic shock; dopamine use is reserved for selected cases.
• Recent warnings about arrhythmia risk and peripheral ischemia emphasize careful dosing and monitoring.

• Store at 20°C to 25°C (68°F to 77°F)
• Protect from light and freezing
• Use freshly prepared or diluted solutions within recommended times (usually within 24 hours at room temperature or 7 days refrigerated)
• Avoid exposure to air and light during infusion