Best Evidence Topics
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In patients with dysrhythmias following tricyclic overdose patients treatment should include alkalinisation to a pH of 7.55

Three Part Question

In a [young adult with dysrhythmias following tricyclic antidepressant overdose] is [treatment with bicarbonate better than no active treatment] at [normalising cardiovascular function]?

Clinical Scenario

A 27 year old woman presents with a history of having taken 30 tricyclic antidepressant tablets 3 hours before admission. ECG monitoring shows frequent dysrhythmias. You wonder whether giving sodium bicarbonate intravenously is worthwhile.

Search Strategy

Medline 1966-12/98 using the OVID interface.
({[exp bicarbonates OR bicarbonate$.mp] AND [antidepressive agents, tricyclic OR exp amitriptyline OR exp imipramine OR exp desipramine OR exp fluoxetine OR tricyclic$.mp]} LIMIT to human AND english language)

Search Outcome

54 papers found of which 43 irrelevant and 7 of insufficient quality for inclusion

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
Brown TC et al
4 children 18 months to 3 yearsCase reportsBlood pressureNormalised
Brown TC
12 children 15 months to 12 years with arrhythmias Sodium bicarbonate 0.5 - 2 mEq/kgObservationalRhythm9/12 reverted to sinus rhythm
Koppel C et al
184 cases of overdose. 8 patients with cardiac disturbance 100 mmol of sodium bicarbonateObservationalRhythm4/8 reverted to sinus rhythm
Hoffmann JR et al
91 patients with overdose Sodium bicarbonate to a pH of 7.55ObservationalBlood pressure20/21 normalised
Rhythm39/49 improved


The evidence for current practice is all based on observational studies. The largest study uses recommends alkalinisation to a pH of 7.55; other studies have used fixed bicarbonate doses. There are no properly designed trials in this area.

Clinical Bottom Line

On current best evidence alkalinisation to a Ph of 7.55 appears to be appropriate therapy for patients with dysrhythmias following tricyclic overdose.


  1. Brown TC, Barker GA, Dunlop ME et al. The Use of Sodium Bicarbonate in the Treatment of Tricyclic Antidepressant-Induced Arrhythmias. Anaest Intens Care 1973;1(3):203-210.
  2. Brown TC. Sodium bicarbonate treatment for tricyclic antidepressant arrhythmias in children Med J Austr 1976;2(10):380-382.
  3. Koppel C, Wiegreffe A, Tenczer J. Clinical Course, Therapy, Outcome and Analytical Data in Amitriptyline and Combined Amitriptyline/Chlordiazepoxide Overdose. Human Exp Toxicol 1992;11(6):458-465.
  4. Hoffman JR, Votey SR, Bayer M et al. Effect of Hypertonic Sodium Bicarbonate in the Treatment of Moderate-to-Severe Cyclic Antidepressant Overdose. Am J Emerg Med 1993;11(4):336-341.