DOPamine

DOPamine

Indication

• To increase cardiac output, blood pressure and urine flow in the treatment of shock which persists after adequate volume replacement; particularly effective in the treatment of cardiogenic shock
• Also used in the short term management of severe congestive heart failure
• Used often following asphyxia
• Used as an adjunct to colloid to maintain adequate blood pressure when tolazoline is used to treat persistent fetal circulation

Pharmacology

• DOPamine is an endogenous catecholamine; it is the immediate precursor of norepinephrine and has a plasma half life of about 2 minutes
• DOPamine creates multiple effects in the body, depending on its dose
• At low doses (< 2 mcg/kg/min), dopamine acts predominantly on specific dopaminergic receptors in the renal, mesenteric, coronary and intracerebral vascular beds to cause vasodilation
• At intermediate doses (2 to 10 mcg/kg/min), beta1-adrenergic receptors are also stimulated and norepinephrine is released from nerve terminals in the myocardium; this produces a positive inotropic effect; overall, there is little change in heart rate, and either reduction or no change in total peripheral resistance
• At higher doses (> 10 mcg/kg/min), alpha- adrenergic receptors are stimulated and these effects predominate (increased peripheral resistance and renal vasoconstriction)

Side Effects

• Tachycardia, angina, palpitations, vasoconstriction, hypertension, hypotension, dyspnea, vomiting, headache, decreased urine output
• Necrosis and sloughing of tissue at IV site if infiltration occurs
• Ventricular arrhythmias can occur at high doses
• Peripheral circulatory impairment - check colour and temperature of extremities

Precautions

• Monitor systemic pressures; check for circulatory impairment
• Watch for dehydration, monitor intake and output
• Should not be inadvertently discontinued, restart infiltrated IVs immediately (drug levels and blood pressure will fall rapidly)
• Monitor IV patency at least every 10-15 minutes
• Local: blanching, tissue ischemia or necrosis may occur with extravasation. Use phentolamine (see phentolamine monograph) if this occurs

Miscellaneous

• Although it is not recommended that medications and TPN (amino acid/dextrose mixture; lipid) be mixed, in some situations there is no alternative. DOPamine has been reported to be physically compatible by visual inspection when "Y'd" in with a mixture of amino acid/dextrose and lipid. In all instances, however, the IV lines should be carefully inspected for any signs of incompatibility (precipitate, change in colour, haze, etc.)

Supplied As

• Commercial premixed 1600mcg/mL solution as 400mg in 250mL D5W
• Supplied by pharmacy as standard concentrations:
  • 0.5kg or less: 800mcg/mL, supplied as 40mg in 50mL D5W
  • Over 0.5kg: 1600mcg/mL, supplied as 80mg in 50mL D5W
• The 1600mcg/mL solution is available as wardstock in the NICU in the main medication fridge as 80mg/50mL syringes
• In HUGO, choose the NICU continuous infusion orderable with the correct weight category and input the desired therapeutic dose (normalized rate) and the rate per hour will be calculated electronically
• Standard Concentration references available on the NICU Intranet here