Dopamine HCl

Dopamine HCl

Class:
  • Beta-adrenergic & alpha-adrenergic agonist
  • Catecholamine
Actions:
  • Low dose (<3 mcg/kg/min): activates dopaminergic receptors in kidneys producing renal artery dilation.
  • Mod dose (3 – 10 mcg/kg/min): primarily activates β1 adrenergic receptors in heart increasing heart rate (positive chronotropic agent), contractility (positive inotropic agent)
  • High dose (10 – 20 mcg/kg/min): activates α-adrenergic receptors producing vasoconstriction (increasing systemic vascular resistance or left ventricular afterload)
Indications:
  • Shock: Moderate doses enhance contractility increasing cardiac output; High doses produce vasoconstriction to enhance blood pressure.
  • Heart Failure:  At moderate doses, dopamine enhances contractility.  Higher doses exacerbate heart failure by increasing afterload and producing additional workload on the heart.
  • Bradycardia:  Dopamine is a 2nd line drug after atropine for bradycardias.
Pharmacokinetics:
  • Onset: < 5 minutes
  • Half-Life: 2 minutes
  • Metabolism:  Liver and kidneys
Adverse Effects:
  • Hypotension, hypertension, tachycardia
  • Anginal pain, ectopic beats, vasoconstriction (cold extremities)
  • Nausea, vomiting, headache
  • Tissue necrosis and sloughing if extravasation occurs
Signs of Toxicity:
  • Hypertension
  • Tachycardia
Contraindications:
  • Tachy-dysrhythmias
  • Ventricular fibrillation
  • Pheochromocytoma
  • Safety during pregnancy, lactation or with children not established.
Dosages & Routes:
  • IV Infusion:  Begin at 2 – 5 mcg/kg/min and titrate to blood pressure according to desired response to a maximum of 20 mcg/kg/min.
Nursing Implications:
  • Drug Interactions:  1) MAO inhibitors potentiate the effects of dopamine (doses must be reduced by 90%); 2) Tricyclic anti-depressants can enhance the effects of dopamine; 3) general anesthetics might increase the risk of dysrhythmias secondary to dopamine; 4) Beta blockers antagonize the beta-adrenergic effects of dopamine; 5) Alpha blockers antagonize the alpha-adrenergic effects of dopamine.
  • Drug Incompatibilities:  sodium bicarbonate, aminophylline, amphotericin B, ampicillin, cephalothin, penicillin G, acyclovir
  • Correct hypovolemia with fluid resuscitation before initiating dopamine infusion.
  • Monitor blood pressure, pulse, and peripheral pulses every 15 minutes.
  • Monitor hourly urine output.
  • Cardiac monitor should be used on patients receiving dopamine infusion.
  • Notify physician immediately if 1) oliguria develops; 2) tachy-dysrhythmias develop; 3) diastolic pressure rises reducing pulse pressure; 4) hypotension continues to exist at maximum dose of 20 mcg/kg/min; 5) signs of peripheral ischemia (purple extremities, cold extremities, diminished peripheral pulses)
  • Weigh patient daily to determine accurate infusion dose.
  • Calculate infusion drips and doses carefully.  Double-check calculations with another nurse or pharmacist.
  • IV site should not be used for any other infusions or IV therapies.
  • Extravasation of dopamine may cause tissue necrosis to skin.  Therefore, monitor IV site every hour.  Have phentolamine (Regitine®) close to the bedside of the patient.

 

References:

American Heart Association. (2006). Handbook of Emergency Cardiac Care (p. 51). Salem, MA: AHA.

Dirks, J.L. (2010) Cardiovascular therapeutic management.  In L.D. Urden, K.M. Stacy, & M.E. Lough's (Eds.) Critical care nursing: Diagnosis and management (6th ed., pp. 546-547).  St. Louis: Mosby Elsevier.

Lehne, R.A. (2010). Pharmacology for nursing care (7th ed., pp. 149-161).  St. Louis: Saunders Elsevier.

Wilson, B.A., Shannon, M.T., Shields, K.M., & Stang, C.L. (2007).  Prentice Hall Nurse's Drug Guide 2007 (pp. 549-550).  Upper Saddle River, NJ: Pearson Prentice Hall.

 

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