Why bicarb in tca overdose

Some of these agents, such as cocaine or diphenhydramine, may show up on rapid toxicology screening or gas chromatography confirmation, but this will only confirm presence of the drug. Laboratory test for serum concentrations to gauge the degree of toxicity will not be available for most of these agents.

Toxic alcohol poisoning can be suspected as part of the differential diagnosis of an elevated anion gap metabolic acidosis. Osmolal gap estimations between measured and calculated osmols may also assist in uncovering the presence of a toxic alcohol, but the absence of an osmolal gap should not be considered definitive evidence to completely rule out the presence of toxic alcohols, particularly ethylene glycol.

Typically the osmolal gap is between 0 to10 but the range may be as wide as -5 to Salicylate concentrations are run by most hospital laboratories and results often return rapidly. The presence of a mixed acid-base disorder on blood gas analysis is often helpful in suggesting this diagnosis when a history is not available. The dosage and administration of sodium bicarbonate depends on clinical indications.

Generally, the target for serum pH is 7. While some have advocated the use of continuous sodium bicarbonate infusions, this has not been well studied.

For salicylates, we recommend the use of continuous infusions of sodium bicarbonate. It is important to remember that typically one ampule of sodium bicarbonate contains mEq of sodium bicarbonate. Potassium supplementation is often also needed to help prevent hypokalemia resulting from intracellular shifting as serum pH rises, and to prevent paradoxical aciduria that can occur during exchange of potassium for hydrogen ions in the distal tubules of the kidney.

Risks of continuous infusion include hypernatremia, hypokalemia, and fluid overload. For treatment of toxic alcohol poisoning, sodium bicarbonate administration should be use in conjunction with dialysis to correct severe acid base disorders. Numerous ampules may be needed to correct the acidemia while dialysis is being initiated. Disclaimer: This website is designed to be informational and educational. Under no circumstance is this website meant to replace the expert advice of a qualified poison specialist or physician.

In the event of a poison emergency, call the nearest poison center immediately by dialing or contact emergency services. UCSF Menu. School of Pharmacy. Search form. Tue Mar 20, Case presentation A 28 year-old woman with a history of depression is brought to the emergency department approximately one hour after an overdose of amitriptyline. Questions What are the indications for the use of sodium bicarbonate in toxicology? By what mechanism does sodium bicarbonate work?

How should sodium bicarbonate be administered? Epidemiology Drugs and toxins that act as sodium channel antagonists include agents listed in List 1.

List 1. Pathophysiology The role of sodium bicarbonate as an antidote depends on the specific indication. Necessary cookies are absolutely essential for the website to function properly. This category only includes cookies that ensures basic functionalities and security features of the website.

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As in the management of other discussed toxidromes, the literature on the benefits of IV sodium bicarbonate originates from case reports and consensus guidelines [ 58 , 59 ]. Beneficial effects of sodium bicarbonate in the management of methanol and ethylene glycol poisoning are believed to be secondary to the formation and enhanced urinary clearance of less toxic metabolites formate [ 59 ]. Acidemia leads to protonation of methanol and ethylene glycol metabolites to uncharged molecules e. The suggested regimen for IV sodium bicarbonate is similar to the above-discussed indications.

However, according to the consensus guidelines, the therapy with IV sodium bicarbonate should be strongly considered when pH falls below 7. As is the case with any treatment involving IV sodium bicarbonate, administration necessitates frequent monitoring of metabolic parameters serum electrolytes and renal function , cardiopulmonary, and renal status of the patient.

It is important to note that symptomatic hypocalcemia should be corrected the routine correction of asymptomatic hypocalcemia is discouraged because of the possible increase in the formation of calcium oxalate crystals in ethylene glycol toxicity. IV administration of sodium bicarbonate may result in enhanced urinary excretion of certain chemicals through urinary alkalinization [ 56 ].

The urinary clearance of methotrexate, phenobarbital, chlorpropamide, and fluoride is increased after reaching urinary pH levels of 7. Metformin toxicity is another instance where sodium bicarbonate may be used [ 60 ]. In rare circumstances such as acute illness and worsening renal function , metformin administration may result in the development of lactic acidosis that is believed to be secondary to mitochondrial dysfunction, with a shift towards anaerobic glycolysis [ 60 — 62 ].

In conclusion, the data on the role of sodium bicarbonate in the management of the above-listed medications is even more limited and cannot be recommended as a first line. Based on the available literature and empiric experience, the IV administration of sodium bicarbonate appears to be beneficial in the management of certain pharmacological toxicities such as sodium channel blockers poisonings, salicylate intoxication, and ingestion of methanol and ethylene glycol. However, most of the data originates from case reports, case series, and expert consensus recommendations.

The data on the management of metformin-associated lactic acidosis, chlorpropamide, methotrexate, and phenobarbital is even more limited. However, it seems very unlikely that randomized controlled trials assessing the impact of sodium bicarbonate will be performed due to ethical concerns. The potential mechanisms of sodium bicarbonate administration include high sodium load, development of metabolic alkalosis with resultant decreased tissue penetration of the toxic substance, and its increased urinary excretion, while, on IV sodium bicarbonate, the patients must be monitored for the development of associated side effects including electrolyte abnormalities hypokalemia, hypocalcemia, and hypernatremia , progression of metabolic alkalosis volume overload, worsening respiratory status volume overload and increased CO 2 production , and worsening metabolic acidosis paradoxical increase in lactic acid production secondary to the activation of glycolytic enzymes.

Frequency of laboratory testing should be individualized. It is important to keep calcium and potassium within normal range to decrease the risk of cardiac arrhythmias. IV administration of sodium bicarbonate represents only one aspect of the complex management of medication and chemical toxicities, and, for a thorough discussion of the management of these toxicities, the reader is referred to focused reviews.

The authors declare that they have no conflicts of interest regarding the publication of this paper. National Center for Biotechnology Information , U. Journal List Int J Nephrol v. Int J Nephrol. Published online Aug 8. Aibek E. Author information Article notes Copyright and License information Disclaimer. Mirrakhimov: moc. Mirrakhimov et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

This article has been cited by other articles in PMC. Abstract Adverse reactions to commonly prescribed medications and to substances of abuse may result in severe toxicity associated with increased morbidity and mortality. Mechanism of Action and Potential Complications of Sodium Bicarbonate Therapy Bicarbonate is an essential chemical regulating the acid-base balance acting as a buffer [ 2 ].

Open in a separate window. Figure 1. Table 1 Constituents and characteristics of commonly used crystalloids and plasma. The Role of Sodium Bicarbonate in the Management of Sodium Channel Blocker Toxicities Sodium channels are essential ion channels responsible for transcellular sodium influx, primarily in cardiac and neurological tissue [ 18 ].

Table 2 List of some drugs with sodium channel blocking properties. Figure 2. The Role of Sodium Bicarbonate in the Management of Salicylate Toxicity Salicylates are a group of pharmacological agents that include aspirin, bismuth salicylate, and local skin preparations such as salicylic acid and methyl salicylate topical preparations that rarely cause toxicity if used in an excessive amount or in patients with skin damage leading to increased absorption [ 51 , 52 ].

The Role of Sodium Bicarbonate in the Management of Methanol and Ethylene Glycol Poisoning Methanol and ethylene glycol are alcohols commonly used in household solutions such as various cleaners, solvents, machine fluids, and antifreeze solutions [ 57 ]. Figure 3. An overview of in vivo methanol and ethylene glycol metabolism. The Role of Sodium Bicarbonate in the Management of Miscellaneous Drug Toxicities IV administration of sodium bicarbonate may result in enhanced urinary excretion of certain chemicals through urinary alkalinization [ 56 ].

Conclusion Based on the available literature and empiric experience, the IV administration of sodium bicarbonate appears to be beneficial in the management of certain pharmacological toxicities such as sodium channel blockers poisonings, salicylate intoxication, and ingestion of methanol and ethylene glycol. Conflicts of Interest The authors declare that they have no conflicts of interest regarding the publication of this paper. References 1.

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