The Role of Sodium Bicarbonate in the Management of Some Toxic Ingestions

Adverse reactions to commonly prescribed medications and to substances of abuse may result in severe toxicity associated with increased morbidity and mortality. According to the Center for Disease Control, in 2013, at least 2113 human fatalities attributed to poisonings occurred in the United States of America. In this article, we review the data regarding the impact of systemic sodium bicarbonate administration in the management of certain poisonings including sodium channel blocker toxicities, salicylate overdose, and ingestion of some toxic alcohols and in various pharmacological toxicities. Based on the available literature and empiric experience, the administration of sodium bicarbonate appears to be beneficial in the management of a patient with the above-mentioned toxidromes. However, most of the available evidence originates from case reports, case series, and expert consensus recommendations. The potential mechanisms of sodium bicarbonate include high sodium load and the development of metabolic alkalosis with resultant decreased tissue penetration of the toxic substance with subsequent increased urinary excretion. While receiving sodium bicarbonate, patients must be monitored for the development of associated side effects including electrolyte abnormalities, the progression of metabolic alkalosis, volume overload, worsening respiratory status, and/or worsening metabolic acidosis. Patients with oliguric/anuric renal failure and advanced decompensated heart failure should not receive sodium bicarbonate.

Trichloroacetic Acid Ingestion: Self-Harm Attempt

Objective

Trichloroacetic acid (TCAA), or trichloroethanoic acid, is a chemical analogue of acetic acid where three methyl group hydrogen atoms are replaced by chlorine. TCAAs are also abbreviated and referred to as TCAs, causing confusion with the psychiatric antidepressant drug class, especially among patients. TCAAs exist in dermatological treatments such as chemical peels or wart chemoablation medication. TCAA ingestion or overdose can cause gastric irritation symptoms including vomiting, diarrhea, or lassitude. This symptomatology is less severe than TCA overdose, where symptoms may include elevated body temperature, blurred vision, dilated pupils, sleepiness, confusion, seizures, rapid heart rate, and cardiac arrest. Owing to the vast difference in symptoms, the need for clinical intervention differs greatly. While overdose of either in a self-harm attempt can warrant psychiatric hospital admission, the risk of death in TCAA ingestion is far less.

Case Report

A patient ingested TCAA in the form of a commercially available dermatological chemical peel as a self-harm attempt, thinking that it was a more injurious TCA.

Conclusion

Awareness among physicians, particularly psychiatrists, regarding this relatively obscure chemical compound (TCAA) and its use by suicidal patients mistakenly believing it to be a substance that can be significantly more lethal (TCA), is imperative.

Associations of Adverse Clinical Course and Ingested Substances among Patients with Deliberate Drug Poisoning: A Cohort Study from an Intensive Care Unit in Japan

Objectives

Some patients with deliberate drug poisoning subsequently have an adverse clinical course. The present study aimed to examine whether the type of drugs ingested and psychiatric diagnoses were related to an adverse clinical course.

Methods

We conducted a cohort study of patients with deliberate drug poisoning admitted to the intensive care unit of a university hospital located in Tokyo, Japan, between September 2006 and June 2013. Intensive care unit (ICU) stay of ≥4 days was used as a primary outcome measure, while the incidence of aspiration pneumonitis was used as a secondary outcome measure. Ingested substances and psychiatric diagnoses were used as explanatory variables.

Results

Of the 676 patients with deliberate drug poisoning, 88% had a history of psychiatric treatment and 82% had ingested psychotropic drugs. Chlorpromazine-promethazine-phenobarbital combination drug (Vegetamin^®) ranked fifth among the most frequently ingested substances in cases of deliberate drug poisoning and had the highest incidence of prolonged ICU stay (20%) and aspiration pneumonitis (29%). The top three major classes consisted of benzodiazepines (79%), new-generation antidepressants (25%), and barbiturates/non-barbiturates (23%). Barbiturate overdose was independently associated with increased odds of both prolonged ICU stay (8% vs. 17%; odds ratio [OR], 2.97; 95% confidence interval [CI], 1.60–5.55) and aspiration pneumonitis (8% vs. 24%; OR, 3.83; 95% CI, 2.18–6.79) relative to those associated with overdose of only other sedative-hypnotics (i.e., benzodiazepines).

Conclusion

These results suggest that judicious prescribing of barbiturates by psychiatrists could reduce the risk of an adverse clinical course when a patient attempts an overdose.

Amitriptyline overdose in emergency department of university hospital: evaluation of 250 patients

OBJECTIVE

The purpose of this study was to evaluate the patients with acute amitriptyline poisoning and investigate predictive factors for the development of life-threatening complications.

METHODS

Demographics, clinical, laboratory, and electrocardiographic (ECG) findings of 250 patients were evaluated retrospectively. Predictive parameters for the development of serious complications were studied.

RESULTS

Median age of patients was 14.6 years, of which, 70% of patients were female and 66% were in pediatric age group. The most common pathological clinical finding and laboratory abnormality were alteration of consciousness and hyponatremia. The rate of convulsive seizure, arrhythmia, and respiratory depression were 17 (6.8%), 16 (6.4%), and 11 (4.4%), respectively. These complications were more seen in pediatric patients than adults (15.8% and 1.2%). The incidence of hyponatremia was more in pediatric patients and severe poisoning groups (38.8 and 53.4%, respectively). The levels of amitriptyline and nortriptyline were significantly higher in the group with complications than the group without complications (p < 0.05). All adult patients were discharged with good prognosis. In pediatric age group, one patient was discharged with severe neurological sequelae and one patient died. QRS duration >100 ms, long corrected QT duration interval, and low Glasgow Coma Score (GCS) at admission were identified as independent risk factors for the development of life-threatening complications (odds ratio: 69.4, 1.9, and 1383, respectively; p < 0.05).

CONCLUSION

Amitriptyline poisoning may be associated with life-threatening complications, especially in pediatric age group and in patients with hyponatremia. Low GCS, presence of hyponatremia, high serum drug levels, and pathological ECG findings on admission may be helpful in predicting the development of complications and poor prognosis.

Seizures during antidepressant treatment in psychiatric inpatients--results from the transnational pharmacovigilance project "Arzneimittelsicherheit in der Psychiatrie" (AMSP) 1993-2008

RATIONALE

There is little clinical data available about seizure rates in psychiatric inpatients, and there are no studies with reference data to the frequencies of antidepressant (AD) use for this important clinical population.

OBJECTIVE

This study investigates seizure rates during AD treatment in psychiatric inpatient settings, drawn from the transnational pharmacovigilance programme Arzneimittelsicherheit in der Psychiatrie (AMSP) in relation to the known frequencies of ADs used in the participating clinics. Comparisons are made to former publications and their limitations.

RESULTS

Seventy-seven cases were identified with grand mal seizures (GMS) during AD treatment between 1993 and 2008, with a total number of 142,090 inpatients under surveillance treated with ADs in the participating hospitals. The calculated overall rate of reported seizures of patients during AD treatment in this collective is 0.05 % for ADs imputed alone or in combination with other psychotropic drug groups and 0.02 % when only ADs were given and held responsible for GMS. The patients receiving tri- or tetracyclic ADs (TCAs) had a 2-fold risk to develop a seizure as compared to the overall average rate in this sample. In 11 cases, there was only one AD imputed--the majority of these cases (9/11) were TCA. Monotherapy with selective serotonin reuptake inhibitors (SSRI) or dual serotonin and noradrenaline reuptake inhibitors (SNRI) were never imputed alone in this sample.

CONCLUSIONS

The results of the study favour the assumption that SSRIs, noradrenergic and specific serotonergic antidepressants (NaSSA) and dual SNRI might be more appropriate than TCAs for the treatment of psychiatric patients with an enhanced seizure risk.

Effects of BQ-788 on amitriptyline-induced cardiovascular toxicity

Objective:

We investigated both the effects of the endothelin type B (ETB) receptor antagonist, BQ-788, on amitriptyline-induced cardiotoxicity and the role of ETB receptors on amitriptyline-induced cardiovascular depression.

Methods:

Male Wistar rats were anaesthetized with urethane/chloralose. Mean arterial pressure (MAP), heart rate (HR) and QRS duration were recorded. Toxicity was induced by amitriptyline infusion (0.94 mg/kg per min) until the 50% inhibition of MAP. In the first protocol, 5% dextrose or BQ-788 bolus was administered to control or experimental group animals, respectively. In the second protocol, after incubation with BQ-788 or 5% dextrose, amitriptyline was infused.

Results:

Amitriptyline caused a significant decrease in MAP, prolonged QRS duration and decreased HR for both the groups. BQ-788 administration improved MAP (5, 10 and 15 min), shortened the prolonged QRS (5 and 10 minutes) and increased HR (5, 10 and 15 min) compared with dextrose group. While all the amitriptyline-infused rats survived in BQ-788 group, all the amitriptyline-infused rats died within 20 min in dextrose group. In the second protocol, BQ-788 incubation did not cause any statistically significant change in amitriptyline-induced cardiovascular depression.

Conclusion:

BQ-788 may have beneficial effects in amitriptyline-induced cardiovascular changes via a physiologic antagonism. ETB receptor antagonists may be the promising antidotes for the cardiovascular toxicity with hypotension and bradycardia.

Tricyclic antidepressants intoxication in Tehran, Iran: epidemiology and associated factors

BACKGROUND

Tricyclic antidepressant (TCA) intoxication contributes a large number of drug toxicities with serious complications. There are a few studies about factors associated with TCA intoxication. This study therefore aimed to identify determinants of this type of intoxication.

METHODS

A cross-sectional study was carried out at Loghman-Hakim Poison Hospital during a 6-month period. All poisoned patients aged >12 years presented to this hospital during the mentioned period were evaluated. Then, TCA-poisoned patients were compared with other drug intoxications as the control group to determine factors associated with TCA intoxications.

RESULTS

There were 9809 admissions, of which 1583 (16.1%) patients including 601 (38%) males were intoxicated with TCAs. Mean age of the subjects was 26.5 + 10 years. Most of the TCA intoxications (74.4%) were intentional (p = 0.01). Amitriptyline was the most frequent agent followed by Nortriptyline. There was no significant difference between TCA and non-TCA intoxications regarding the mortality (1.3% in TCA vs. 1.1% in others, p = 0.45). Logistic regression analysis revealed that sex, addiction status, and history of psychological problems have association with TCA intoxication.

CONCLUSIONS

The results of this study are helpful in identifying individuals who are prone to TCA intoxication and may be useful in implementation of preventive strategies.