Dopamine

Aka: Dopamine, Intropin, Dopamine Hydrochloride

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II. Definitions

  1. Dopamine
    1. Endogenous Catecholamine with Dopaminergic and B1 activity
    2. Has largely been replaced by Norepinephrine as a Vasopressor in adult shock (but still used in pediatric shock)
    3. Increases cardiac contractility, systolic Blood Pressure and to a lesser extent Heart Rate
    4. Has dose related effects with preserved renal and CNS perfusion at lower doses

III. Physiology: Dopamine as an CNS Endogenous Neurotransmitter

  1. Dopamine is an endogenous Catecholamine
  2. Dopamine is synthesized in vivo from Tyrosine (via Dopa)
  3. Two Dopamine receptors are identified (D1, D2)
    1. Activation of either receptor inhibits Neuronal firing
    2. Apomorphine is an endogenous D2 Agonist
    3. Many Antipsychotics inhibit adenylate cyclase release on D1 receptor activation
  4. Dopaminergic Pathways
    1. Substantia Nigra to striatum (nigrostriatal pattern, affected in Parkinsonism)
    2. Medulla ChemoreceptorTrigger Zone (Vomiting)
    3. Hypothalamus to the pituitary intermediate lobe (Prolactin release)

IV. Mechanism

  1. Half life of Dopamine is short and requires infusion
    1. As with other Catecholamines, rapidly metabolized by COMT and MAO (A in brain, B peripherally)
  2. Low dose (2-5 mcg/kg/min)
    1. Increases splanchnic flow
    2. Increases coronary perfusion
    3. Increases cerebral flow
    4. Increases renal perfusion
      1. Previously recommended for oliguric Renal Failure
      2. No longer recommended due to lack of GFR effect
  3. Mid-dose (5-10 mcg/kg/min)
    1. Direct Beta Adrenergic Receptor effects
      1. Increases cardiac contractility
      2. No effect on Blood Pressure
      3. No effect on Heart Rate
    2. Stimulates Norepinephrine release
      1. Effect blunted if Norepinephrine stores depleted
  4. High Dose (10-20 mcg/kg/min)
    1. Increase in Blood Pressure
    2. Tachycardia may be significant
    3. Vasoconstriction of renal and splanchnic beds (with decreased GFR)

V. Indications

  1. Has largely been replaced by Norepinephrine as a Vasopressor in adult shock (but still used in pediatric shock)
  2. Hemodynamically significant Hypotension
    1. Systolic Blood Pressure under 90 mmHg
    2. Poor Tissue perfusion
      1. Oliguria or Anuria
      2. Altered Level of Consciousness
    3. No Hypovolemia
  3. Hypotension following Resuscitation
    1. Symptomatic Bradycardia
    2. Return of Spontaneous Circulation

VI. Contraindications: Absolute

  1. Pheochromocytoma
    1. Risk of Hypertensive Crisis

VII. Contraindications: Relative (or use low dose Dopamine)

  1. Increased vascular resistance
  2. Pulmonary congestion or Congestive Heart Failure
  3. Increased Preload

VIII. Precautions

  1. Dopamine has been largely replaced by Norepinephrine in adults in U.S.
    1. Theoretically safer than Norepinephrine when used peripherally
      1. However Norepinephrine is often initially used via a reliable peripheral IV safely
    2. Theoretically with greater renal protection than other Vasopressors
      1. Does not appear to offer any significant benefit over other Vasopressors in renal protection
  2. In children, Dopamine is still a first-line Vasopressor despite risks
    1. See the adverse effects (e.g. Dysrhythmia) below
    2. Dopamine is asssociated with a three fold increased mortality in septic children
      1. Ventura (2015) Crit Care Med 43(11): 2292-302 +PMID: 26323041 [PubMed]

IX. Dosing: Pediatric Infusion (Same as Dobutamine preparation)

  1. Preparation
    1. Draw up "x" mg of Dopamine
    2. Where "x" = 6 x Weight in Kilograms
    3. Add enough D5W or NS to Dopamine for 100 ml total
    4. At this dilution
      1. Infusion rate of 1 ml/h provides 1.0 ug/kg/min
  2. Start Dose: 5 to 10 mcg/kg/min (5 to 10 ml/hour)
  3. Titrate to effect
    1. Perfusion
    2. Urine Output
    3. Blood Pressure

X. Dosing: Adult Infusion

  1. Preparation
    1. Start with 1 ampule Dopamine (400 mg)
    2. Option 1: Dissolve 400 mg (1 ampule) Dopamine in 250 ml D5W
      1. Final Concentration: 1600 mcg/ml
      2. Weight 70 kg: Infusion rate 13 ml/h provides 5 mcg/kg/min
    3. Option 2: Dissolve 800 mg (2 ampules) Dopamine in 250 ml D5W
      1. Final Concentration: 3200 mcg/ml
      2. Weight 70 kg: Infusion rate 6.5 ml/h provides 5 mcg/kg/min
  2. Start Dose: 5 mcg/kg/min
  3. Titrate: increase by 5 to 10 mcg/min every 10 min to 5-20 mcg/kg/min (maximum 50 mcg/kg/min) to clinical response
    1. Perfusion
    2. Urine Output
    3. Mean arterial pressure or systolic Blood Pressure

XI. Adverse Effects

  1. Tachycardia
    1. Increases myocardial oxygen demand
  2. Arrhythmias
    1. Premature Ventricular Contraction (PVC)
    2. Supraventricular Tachycardia (SVT)
    3. Ventricular Tachycardia (VT)
  3. Hypertensive Crisis
  4. Increases Pulmonary artery wedge pressure
    1. May worsen pulmonary congestion
    2. May provoke Congestive Heart Failure
  5. Gastrointestinal
    1. Nausea and Vomiting

XII. Precautions

  1. Avoid Dopamine dose over 20 ug/kg/min
    1. Results in severe Vasoconstriction and ischemia
    2. Consider adding Norepinephrine if inadequate BP
  2. Use caution with Dopamine in Congestive Heart Failure
    1. Consider adding Vasodilator
      1. Nitroprusside
      2. Nitroglycerin
    2. Consider using Dobutamine instead of Dopamine
  3. Taper Dopamine gradually to avoid Hypotension
  4. Use Dopamine via central venous catheter
    1. Extravasation causes severe local tissue ischeme and necrosis
    2. Antidote for extravasation
      1. Phentolamine 5-10 mg diluted in 10-15 ml NS
      2. Infiltrate area of extravasation with Phentolamine

XIII. Drug Interactions

  1. Sodium Bicarbonate inactivates Dopamine
    1. Also occurs with Epinephrine
  2. Monoamine Oxidase Inhibitors potentiate Dopamine effect
    1. Use only one tenth of regular dose
  3. Bretylium effects may be synergistic with Dopamine
  4. Phenytoin may cause Hypotension with Dopamine

XIV. Resources

  1. Dopamine Injection Solution (DailyMed)
    1. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=7896052c-2a72-ca89-e053-2a91aa0ae86e

XV. References

  1. Goldberg (2015) Crit Dec Emerg Med 29(3): 9-19
  2. McCollum in Herbert (2019) EM:Rap 19(7):4-6

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