Experimental tricyclic antidepressant toxicity: a randomized, controlled comparison of hypertonic saline solution, sodium bicarbonate, and hyperventilation

Ann Emerg Med. 1998 Sep;32(3 Pt 1):329-33. doi: 10.1016/s0196-0644(98)70009-5.


Study objective: We sought to compare the effects of hypertonic sodium chloride solution (HTS), sodium bicarbonate solution, and hyperventilation (HV) on severe tricyclic antidepressant (TCA) toxicity in a swine model.

Methods: Twenty-four mixed-breed, domestic swine of either sex were given an intravenous infusion of nortriptyline (NT) until development of both a QRS duration longer than 120 ms and a systolic blood pressure (SBP) less than or equal to 50 mm Hg. Animals were randomly assigned to 1 of 4 groups. On reaching toxicity, the control group received 10 mL/kg of 5% dextrose in water (D5W); the HTS group received 10 mL/kg of 7.5% NaCl solution (15 mEq Na+/kg); the NaHCO3 group received 3 mEq/kg of 8.4% sodium bicarbonate solution followed by enough D5W solution to equal 10 mL/kg of total volume; and the HV group was mechanically hyperventilated to maintain arterial pH between 7.50 and 7.60 and given 10 mL/kg of D5W.

Results: The mean SBP 10 minutes after treatment was 54+/-18 mm Hg in the control group, 134+/-21 mm Hg in the HTS group, 85+/-19 mm Hg in the NaHCO3 group, and 60+/-12 mm Hg in the HV group (P<.05). Mean QRS duration 10 minutes after treatment was 144+/-38 ms in the control group, 80+/-14 ms in the HTS group, 105+/-38 ms in the NaHCO3 group, and 125+/-46 ms in the HV group (P<.05).

Conclusion: In this model of TCA, toxicity HTS was more effective than sodium bicarbonate. Hyperventilation had little effect. Sodium loading may be the most important factor in reversing TCA toxicity.

Publication types

  • Comparative Study

MeSH terms

  • Animals
  • Antidepressive Agents, Tricyclic / adverse effects*
  • Blood Pressure / drug effects
  • Buffers
  • Disease Models, Animal
  • Electrocardiography / drug effects
  • Female
  • Fluid Therapy
  • Glucose / administration & dosage
  • Glucose / therapeutic use
  • Hydrogen-Ion Concentration
  • Injections, Intravenous
  • Male
  • Nortriptyline / adverse effects*
  • Random Allocation
  • Respiration, Artificial* / methods
  • Saline Solution, Hypertonic / administration & dosage
  • Saline Solution, Hypertonic / therapeutic use*
  • Sodium / blood
  • Sodium / therapeutic use
  • Sodium Bicarbonate / administration & dosage
  • Sodium Bicarbonate / therapeutic use*
  • Swine
  • Tachycardia, Ventricular / chemically induced
  • Tachycardia, Ventricular / drug therapy


  • Antidepressive Agents, Tricyclic
  • Buffers
  • Saline Solution, Hypertonic
  • Sodium Bicarbonate
  • Sodium
  • Nortriptyline
  • Glucose