UMEM Educational Pearls - Toxicology


COVID-19 pandemic has brought two old medications – chloroquine and Hydroxychloroquine – back from the past. 

A couple in Arizona self-medicated with chloroquine this week and experienced chloroquine toxicity; the man died and his wife was admitted to the ICU.

Chloroquine and hydroxychloroquine overdose result in cardiotoxicity by Na and K channel blockade (similar to other membrane stabilizing agents such as TCAs, loperamide, etc.). Onset of toxicity is usually within 1 – 3 hours after ingestion.

Other symptoms of toxicity include: nausea/vomiting, respiratory depression/apnea, altered mental status and seizure. Hypokalemia is often encountered.

Use of sodium bicarbonate is controversial due to worsening of hypokalemia. Instead, administration of high dose diazepam and epinephrine (EPI) infusion has shown to decrease mortality (see below).

Riou B et al. NEJM 1988 DOI: 10.1056/NEJM198801073180101

  • A retrospective control (n=11) vs. prospective diazepam (2 gm/kg daily) and EPI (0.25 microgm/kg/min with titrate to SBP >= 100 mmHg) group (n=11) involving large chloroquine ingestion (> 5 mg)


  • Combination treatment group: 91%
  • Control: 9%


Clemessy JL et al. Crit Care Med 1996. DOI:10.1097/00003246-199607000-00021

  • 5 year retrospective study (n=167)
  • Mean chloroquine ingestion: 4.5 gm +/- 2.8 gm
  • >5 gm ingestion: 43 (26%)

Treatment: 87% received at least one of the interventions below.

  • 79/167 (48%) received EPI infusion
  • 142/167 (85%) received diazepam
  • Mechanical ventilation: 123/167 (74%)


  • Overall: 8.4%
  • >5 gm ingestion: 9.3%

Bottom line

  • Chloroquine and hydroxychloroquine toxicity may increase due to COVID19 pandemic
  • Limited studies show that combined therapy of high dose diazepam and epinephrine infusion may decrease mortality associated with chloroquine and hydroxychloroquine toxicity.

Category: Toxicology

Title: Can acetaminophen cause methemoglobinemia?

Keywords: acetaminophen overdose, methemoglobinemia (PubMed Search)

Posted: 3/19/2020 by Hong Kim, MD, MPH
Click here to contact Hong Kim, MD, MPH


Methemoglobinemia occurs when iron in the hemoglobin is converted from ferrous (2+) to ferric (3+) state, frequently by substance exposure. There are many medications and chemicals that can induce methemoglobinemia. 

Common agents that induce methemoglobinemia include:

  • Nitrites/nitrates
  • Local anesthetics (benzocaine, lidocaine)
  • Nitroglycerin
  • Nitroprusside
  • Phenazopyridine
  • Quinones
  • Sulfonamides
  • Analine
  • Naphthalene
  • Dapsone
  • Nitric oxide

Acetaminophen has not been associated with methemoglobinemia. However, two cases of methemoglobinemia in massive acetaminophen overdose were recently reported. Both patients were not on any medication known to cause methemoglobinemia.

Case 1:  54 year-old man with DM, HTN, cognitive impairment and no hx of G6PD deficiency hospitalized for altered mental status

  • pH: 7.2
  • lactic acid: 14.5 mmol/L
  • APAP: 531 mcg/mL
  • Discrepancy between pulse oximetry and arterial blood gas led to checking the methemoglobin level – 32%
  • Developed coagulopathy (INR 9.8) with AST/ALT 3487/2837

Case 2:  64 year-old man with dementia, polysubstance abuse, depression and hypertension hospitalized from nursing home for altered mental status. 

  • pH: 7.25
  • AG: 28
  • APAP: 730 mcg/mL
  • Methemoglobin level: 12%
  • AST/ALT: 44/46


  • It is unlikely that significant methemoglobinemia will develop in the majority of the APAP overdose.
  • However, methemoglobinemia should be considered in a large APAP overdose in select clinical scenarios (e.g. pulse oximetry and arterial blood gas discrepancy).

Show References

Category: Toxicology

Title: Predictors of mortality in Metformin associated lactic acidosis

Keywords: mortality, predictors, MALA, pH, lactate (PubMed Search)

Posted: 2/12/2020 by Hong Kim, MD, MPH (Emailed: 2/13/2020)
Click here to contact Hong Kim, MD, MPH


Metformin associated lactic acidosis (MALA) has a high rate of mortality, ranging from 25% to 50%. Lactate level and acidemia are frequently associated with poor clinical outcome in many disease/medical conditions (e.g. sepsis).

A study investigated, via meta-analysis, if lactate level and pH were predictive of mortality in MALA.


44 studies were identified from PubMed, EMBASE and Web of Science.

170 cases of MALA were included

  • Median age: 68.5 years
  • Median pH: 7.02
  • Median lactate: 14,45 mmol/L
  • Overall mortality: 36.2%

pH and lactate were poor predictors of mortality based upon ROC curve

  • pH: AUC of 0.430
  • lactate: AUC of 0.593


  • MALA was associated with high mortality in this meta-analysis: 36.2%
  • pH and lactate were poor predictors of mortality. 

Category: Toxicology

Title: Predictors of fatality from intentional drug overdose

Keywords: risk of death, intentional drug overdose (PubMed Search)

Posted: 1/23/2020 by Hong Kim, MD, MPH
Click here to contact Hong Kim, MD, MPH


Intentional drug overdose (IDO) can lead to significant morbidity and can increased patient's risk of death. A study was recently performed to identify the predictors of death in a cohort of patient who intentionally overdose on drug(s). 

National Self-Harm Registry and National Drug-Related Death Index were reviewed (between January 1st, 2007 and December 31st, 2014) to identify the study cohort.



Non fatal IDO

Fatal IDO

Number of cases









Age, years (median)



Multiple drug ingestion




Risk of death

  • 1.7 times higher in MALE compared to female
  • 5 times higher in age > 45 years vs. 15-24 years
  • 3 times higher in patient who ingested 2 – 5 distinct agents, 6x higher in > 6 agent vs. single agent
  • 15 times higher after TCA ingestion
  • 12 times higher after opioids ingestion
  • 4 times higher after antidepressants or illicit substance ingestion/exposure


  • Older age (> 45 years), male gender and ingestion of multiple agents (>2) were associated with higher risk of death from intention drug overdose.

Show References

Category: Toxicology

Title: Risk of fatality after ED visit for non fatal opioid overdose

Keywords: non-fatal opioid overdose, risk of fatality (PubMed Search)

Posted: 1/16/2020 by Hong Kim, MD, MPH
Click here to contact Hong Kim, MD, MPH


Many patients are treated in the emergency room for non-fatal opioid overdose. However, it is unknown what proportion of these patient population experience subsequent fatality after their ED visit. 

A recent study investigated the 1-year mortality rate among Massachusetts ED patients who were treated and discharged from ED for non-fatal opioid overdose.


  • 11,557 patients were identified between July 1, 2011 and September 30, 2015.
  • There were 635 fatalities (5.5%) within 1 year in this cohort.
    • Of these, 428 (67.4%) died due to opioid overdose

Of those who died, 

  • 130 (20.5%) died within 1 month
  • 29 (4.6%) died within 2 days.

Manner of death

  • Natural causes: 121 (19.1%)
  • Accidental: 460 (72.4%)
  • Suicide: 13 (2.0%)
  • Other/pending investigation: 41 (6.5%)

Place of death

  • Hospital: 310 (48.8%)
  • Residence: 146 (23.0%)
  • Other/unknown/nursing home: 179 (28.2%)


  • There is high rate of fatality within 1 month (20.5%) after non-fatal opioid overdose ED visits.
  • Subsequent fatal opioid overdose was observed in 428 (67.4%) of the cohort.

Show References

Category: Toxicology

Title: Pharmacobezoar formation in acetaminophen

Keywords: acetaminophen, pharmcobezoar (PubMed Search)

Posted: 1/2/2020 by Hong Kim, MD, MPH
Click here to contact Hong Kim, MD, MPH


Pharmacobezoars (clumps of medication/pills) formation has been demonstrated in few medications such as aspirin, and ferrous sulfate tablets. Their presence can alter management due to prolonged absorption and may cause GI obstruction.

Acetaminophen (APAP) is a commonly available over-the-counter medication that is often implicated in an acute overdose event. A recently published in-vitro study (using pig stomach) investigated whether APAP can form a pharmacobezoar.

APAP group/dosage

  • 25 gm (50 tablets)
  • 37.5 gm (75 tablets)
  • 50 gm (100 tablets)

Positive control group

  • ferrous sulfate (15 gm/50 tablets)

Negative control group

  • chlorpheniramine (200 mg (50 tablets)


  • APAP formed clumps in 37.5 gm and 50 gm groups
  • 83% (5 out of 6) of the 25 gm APAP group did not form clumps.
  • Dissolution profile: APAP clumps released more slowly (over 60 min tested) compared to individual tablet without reaching a peak.


  • APAP can form pharmacobezoar at doses greater than 37.5 gm (in-vitro model) and can result in prolonged or delayed toxicity due to pharmacobezoar formation.

Show References


Non-opioid medications such as gabapentin are frequently prescribed for the management of pain. 

A retrospective study of the National Poison Data System (data collected by the U.S. Poison Centers) from 2013 – 2017 showed increasing trend of gabapentin exposure.

Gabapentin exposure increased between 2013 and 2017 by:

  • Total exposure: 72.3% 
  • Isolated intentional suicide attempt: 80.5%
  • Isolated exposure: 67.1%
  • Isolated intentional abuse/misuse: 119.9%

5 most commonly co-ingested substances with gabapentin

  • Sedative-hypnotic: 22.9%
  • Antidepressant: 12.7%
  • Antihypertensive: 9.9%
  • Opioid: 9.0%
  • Antipsychotics: 6.3%

16.7% of the isolated gabapentin exposure required hospitalization.



  • Gabapentin abuse/misuse and ingestion with self-harm intent is increasing in the U.S.

Category: Toxicology

Title: Safety of Droperidol use for agitation in the emergency department

Keywords: droperidol, agitation, sedation, QT prolongation (PubMed Search)

Posted: 12/5/2019 by Hong Kim, MD, MPH
Click here to contact Hong Kim, MD, MPH


After many years of national shortage and FDA’s black box warning in 2001 (QT prolongation) droperidol is slowing becoming available.

In 2015, a prospective observational study was published involving ED patients who received droperidol for agitation (acute behavioral disturbance). 


  • Study period: August 2009 to April 2013 in 6 EDs in Australia
  • Intervention: droperidol 10 – 20 mg IM or IV (if available)
  • EKG performed within 2 hours of droperidol administration.
  • QT was manually measured and plotted against the heart rate on the QT nomogram – if above “at-risk line” = abnormal


  • Droperidol was administered in 1,403 ED patients
  • EKG available in 1,009 ED patients
  • Median age: 34 years (IQR: 25-44)
  • Men: 59.9%

Four leading reason for ED presentation

  1. Alcohol intoxication: 421
  2. Deliberate or threatened self-harm: 200
  3. Psychostimulant use: 130
  4. Mental illness/psychosis: 142
  • Median droperidol dose: 10 mg (IQR: 10 to 17.5 mg) 
  • Abnormal QT interval: 13 (1.3%, 95% CI: 0.3% to 2.3%)
    • 7 patient had other potential contributing factors: methadone, escitalopram, Amiodarone or preexisting condition. 
  • Median time to sedation: 20 min (IQR: 10 to 30 min)

Adverse events

  • Desaturation (<90%): 22 (1.6%)
  • Airway obstruction: 8 (0.6%)
  • Hypotension: 28 (2.0%)
  • Extrapyramidal symptoms: 7 (0.5%)
  • Arrhythmia: 1 (0.1%)
  • Hypoventilation (RR < 12 breaths/min): 4 (0.2%)
  • Seizure: 1 (0.1%)
  • No adverse events: 1,333 (95.0%)


  • Droperidol is a safe sedating agent with no evidence of increased risk for QT prolongation with the doses used. 

Show References


As of November 20, 2019:

2290 cases of e-cigarette, or vaping, product use-associated lung injury (EVALI) from 49 states (except Alaska), District of Columbia and 2 U.S. territories.

  • Largest number of cases (150-199) reported from CA, TX and IL
  • 47 deaths

Analysis of 29 bronchoalveolar lavage (BAL) fluid samples from EVALI patients submitted to CDC from 10 states showed:

  • Vitamin E acetate in all samples 
  • THC: 82%
  • Nicotine: 62%
  • No other chemicals of concern were identified (e.g. plant oil, mineral oil, terpenes, etc.) 

*** Vitamin E acetate appears to be associated with EVALI but the investigation is continuing.*** 

  • Oral ingestion of vitamin E acetate does not cause harm.
  • High dose vitamin E supplementation (>2000 IU/day [2000 mg/day]) can cause GI symptoms: nausea, vomiting, diarrhea and abdominal pain.

Some research has suggested that oral vitamin E use has potential beneficial effects (i.e. anti-inflammatory/antioxidant) in the lung (e.g. asthma and allergic lung disease), cardiovascular disease and prostate cancer (Cook-Mills JM et al. 2013; Jiang Q et al. 2001)

Common uses of vitamin E

  • Topical cosmetic skin products (skin cream) for antioxidant effect.
  • Essential dietary vitamin (fat soluble) found in many food items and as dietary supplement.
  • In vaping products: vitamin E is used as an additive/thickening agent in THC containing e-cigarette, or vaping products.

There is limited to no data on pulmonary effect of vitamin E from inhalation in the scientific literature.

Stay tuned for additional updates from CDC.

Show References

Category: Toxicology

Title: Observation for the development of metformin associated lactic acidosis after an acute metformin overdose

Keywords: meformin overdose, metformin associated lactic acidosis, observation period (PubMed Search)

Posted: 11/14/2019 by Hong Kim, MD, MPH
Click here to contact Hong Kim, MD, MPH


Metformin is one of the most commonly prescribed oral hypoglycemic agents. Metformin associated lactic acidosis (MALA) is uncommon but potentially life-threatening complication of metformin overdose. 

Lactic acidosis occurs due to inhibition of mitochondrial glycerophosphate dehydrogenase, resulting in decreased conversion of lactic acid to pyruvate.

A small retrospective study (using Illinois Poison Center data) attempted to characterize the development of MALA after an acute overdose.

MALA was defined as 

  • Lactate: > 5 mmol/L
  • Acidemia: (HCO3< 20 mmol/L or pH < 7.35)


40 cases of MALA identified between Jan. 2001 to Dec. 2014

  • Meadian age: 41 year
  • Female: 55%
  • Acute on chronic ingestion: 62.5%
  • Hypoglycemia: 3 (7.5%)

Time to development of MALA (n=30)

  • <=6 hours: 18 (60%)
  • 6-12 hours: 9 (30%)
  • >12 hours: 3 (10%)
  • Unknown: 10

Death: 1 (2.5%)



  1. The majority of MALA developed within 6 hours. However, delayed onset of MALA can occur, up to 12 hours post ingestion.
  2. Minimum of 12 hour of observation is recommended after an acute metformin overdose.

Show References

Category: Toxicology

Title: Use of droperidol for cannabinoid hyperemesis syndrome

Keywords: droperidol, cannabinoid hyperemesis syndrome, recurrent nausea/vomiting (PubMed Search)

Posted: 11/7/2019 by Hong Kim, MD, MPH
Click here to contact Hong Kim, MD, MPH


Droperidol has recently become available again in select U.S. institutions. It has been used as an antiemetic and to treat agitation prior to the FDA’s black box warning (for QT prolongation) and national shortage. 

Recently, a retrospective study was conducted (Melbourne, Australia) in the use of droperidol in the management of cannabinoid hyperemesis syndrome (CHS).


689 medical records were identified from January 2006 to December 2016.

76 cases met diagnostic criteria of CHS (below)

  • Long-term cannabis use
  • Symptoms of recurrent vomiting
  • Absence of illness that could otherwise explain symptoms.

Droperidol group (DG) = 37; no droperidol group (NDG)= 39 

Median length of stay: 

  • DG: 6.7 hr vs. NDG: 13.9 hours (p=0.014)

Median time to discharge after final drug administration: 

  • DG: 137 min (IQR: 65, 203) vs. NDG: 185 min (IQR: 149, 403)

Frequency of droperidol (dose) used: 

  1. 0.625 mg (n=25)
  2. 1.25 mg (n=20)
  3. 2.5 mg (n=17)

Metoclopramide and Ondansetron use in non-droperidol group was twice that of droperidol group


  • Droperidol use to treat CHS associated nausea/vomiting resulted in decreased length of stay and lower use of antiemetics.  


Patients with drug-induced cardiogenic shock [DIC] (e.g. overdose of CCB/BB, membrane stabilizing agents, etc.) are often managed with medical interventions such as vasopressors, bicarbonate infusion, high-dose insulin, lipid emulsion therapy. A fraction of these patients may be refractory to the standard medical therapy. VA-ECMO (venoarterial extracorporeal membrane oxygenation) has been utilized in such situation; yet clinical experience of using VA-ECMO in DIC is limited.

A recent retrospective study of the Extracorporeal Life Support Organization’s ECMO registry showed

  • Increasing VA-ECMO utilization for drug-induced cardiogenic shock (n=104) over the past 15 years (2003 to 2018) but it represents a fraction (0.067%) of VA-ECMO use.
  • VA-ECMO improved hemodynamic and metabolic status at 24 hrs-post cannulation.
  • Persistent acidosis (HCO3 level) and acidemia (pH) at 24 hrs-post cannulation was associated with mortality.
  • 52.9% of the cases survived to discharge. 


  • VA-ECMO may be clinically beneficial (improvement of hemodynamic and metaboic status) in patients with refractory drug-induce cardiogenic shock

Show References

Category: Toxicology

Title: Trend of suicide attempt in adolescent and young adults

Keywords: suicide attempt, adolescent, young adults, epidemiological trend (PubMed Search)

Posted: 10/10/2019 by Hong Kim, MD, MPH (Updated: 3/3/2024)
Click here to contact Hong Kim, MD, MPH


The rate of suicide attempt has been increasing over the past decade. A recently published article investigated the temporal trend of suicide attempts in adolescent/young adult population (10 – 25 years old) from 2000 to 2018.


  • All intentional – suspected suicide cases were identified from the National Poison Data System from Jan 1, 2000 to December 31, 2018. 
  • Following age groups were compared: 10-12, 13-15, 16-18, 19-21 and 22-25 years old.


  • A total of 1,677,435 cases were identified with 0.1% fatality (n=1579).
  • Female: 70.6% (n=1,184,691) 
  • Single substance (64.1%; n=1,074,423)
  • Highest suicide attempt rate: 16-18 years (30.1%; n=504,682)
  • Lowest suicide attempt rate: 10-12 years (2.3%; n=38,428)
  • The suicide attempt rate increased significantly starting 2011 in 10-12, 13-15 and 16-19 years age groups with seasonal trend
    •  Higher during school months (Sept to May) vs. non-school months (June-August)

Top 5 substance involved in suicide attempt

  1. OTC analgesics
  2. Antidepressants
  3. Sedative hypnotics
  4. Antihistamines
  5. Antipsychotics

Agents associated with serious medical outcome (after 2011)

  1. Antidepressants
  2. OTC analgesics
  3. Antihistamines 
  4. ADHD medications
  • ADHD medicaitons: common in 10-15 years population
  • Sedative hypnotics (e.g. benzodiazepines): common in older age group (16-25 years)


  • Rate of suicide attempt in adolescent and young adults has increase, especially since 2011.
  • The substance used in suicide attempt usually involves medications available to the specific age group.
  • OTC medications (analgesics and antihistamines) were involved in a third of the suicide attemps.

Show References

Category: Toxicology

Title: Clinical and demographic characteristics of e-cigarrette exposure: 2010-2018

Keywords: e-cigarrette liquid exposure, National Poison Data System (PubMed Search)

Posted: 10/3/2019 by Hong Kim, MD, MPH
Click here to contact Hong Kim, MD, MPH


E-cigarette (vaping) use has become increasingly popular over the past 10 years, especially among adolescents. Intentional exposure (i.e. ingestion in self harm) of nicotine (e-cigarette liquid) can be life threatening where it can produce mixture of stimulatory (early), cholinergic toxicity and muscle paralysis/respiratory failure by blocking the neuromuscular junction. However, the severity of clinical toxicity in unintentional exposure can vary widely depending on the dose/route/circumstance of their exposure.

A recently published study investigated the characteristics of e-cigarette liquid exposure between Jan 1, 2010 to Dec 31, 2018 using the National Poison Data System


  • Total reported exposure: 17,358.
  • e-cigarette exposure report increased starting 2013 (n=1435), peaking in 2014 (3742). 2018 (n=2901).

Top 4 clinical/demographic characteristics are listed below.

Age group:

  • < 5 years: 64.8%
  • 25+ years: 15.4%
  • 18-24 years: 8.3%
  • 12-17 year: 3.4%

Route of exposure

  • Ingestion: 77.5%
  • Dermal: 13.0%
  • Inhalation/nasal: 10.4%
  • Ocular: 7.1% 

Level of care:

  • Not referred to health care facility (HCF): 60.9%
  • Treated and released from HCF: 27.4%
  • Admitted: non-critical care: 0.8%, critical care: 0.6%

Clinical effects - overall

  • Vomiting: 25.4%
  • Nausea: 11.8%
  • Ocular irritation: 11.3%
  • Dizziness/vertigo: 5.1%

In <5 years group

  • Vomiting: 47.1%
  • Cough/choking: 10.2%
  • Drowsiness/lethargy: 5.7%
  • Nausea: 5.5%


  • e-cigarette exposure predominantly occurs in young children (< 5 y/o)
  • Clinical toxicity are usually self-limited and often not referred to HCF.
  • Severe toxicity is possible, although infrequent, from unintentional exposure.

Show References

Category: Toxicology

Title: Capsaicin for cannabinoid hypermesis syndrome?

Keywords: capsaicin, cannabinoid hyperemesis syndrome, marijuna use. (PubMed Search)

Posted: 9/19/2019 by Hong Kim, MD, MPH
Click here to contact Hong Kim, MD, MPH


Cannabinoid hyperemesis syndrome [CHS] (i.e. cyclic/recurrent nausea, vomiting and abdominal pain) is associated with long-term and frequent use of marijuana. Patients with CHS often report temporary relief of symptoms with hot water/shower exposure. Emergency room providers may encounter a growing number of patients with CHS with increasing legalization of marijuana-containing products.

Topical capsaicin has been gaining interest as a potential adjunct to the conventional management of patients with CHS (e.g. antiemetics, opioids, benzodiazepines and antipsychotics).

A small retrospective study was performed involving 43 patients who had multiple visits, and were treated with and without capsaicin. The primary outcome was the ED length of stay (LOS).


  • Most frequently administered medications in both groups were:
  1. Anti-emetics
  2. Haloperidol
  3. Diphenhydramine 
  • Median ED LOS: no significant difference
    • Capsaicin vs. non-capsaicin: 179 min (IQR: 147, 270) vs. 201 min (IQR: 168, 310) (p=0.33)
  • Capsaicin group showed
    • Decreased opioid used: 69 mg vs. 166.5 mg oral morphine equivalents
    • Fewer additional medication administration: 3 vs. 4 doses (p=0.015)
    • Shorter median time to discharge after last medication administration: 60 min (IQR: 35, 115) vs. 92 min (IQR: 47, 155) (p=NS) 
  • 67% of the visit where capsaicin was used required no additional medication.



  • Capsaicin use did not decrease ED LOS.
  • However, there was a decrease in total medications administered and opioid requirement.

Show References

Category: Toxicology

Title: Officer, I'm not drunk. I just used a mouth wash!

Keywords: ethanol, breath analyzer, mouth wash (PubMed Search)

Posted: 9/12/2019 by Hong Kim, MD, MPH
Click here to contact Hong Kim, MD, MPH


Breath analyzers are commonly used by law enforcment officers to test for alcohol intoxication. Breath analyzer uses ethanol partition ratio between blood:breath of 1:2100 = 1 gm of ethanol in 2100 mL of breath/air.

Mouth wash products are frequently used for oral hygiene, and at times, to "mask" odor of substances. These products are readily available in any grocery stores or pharmacy and contain upto 26.9% ethanol (e.g. Listerine) (18.9% - Scope; 14.0% - Cepacol).  

Recently, a small study using healthy volunteers (n=11) was published to investigate the impact of limited ethanol exposure (mouth wash and ethanol vapor) on the breath-alcohol concentration (BrAC).



  1. Ethanol vapor exposure (856 mg/m3) for 15 minute. 
  2. Oral rinse (for 30 sec) using mouth wash containing 22% ethanol, 1 hour after the ethanol vapor exposure
  3. Blood and breath samples were collected before, between and after exposure.



Blood: No or very low levels of ethanol (0.002 mg/g) were detected in blood at all collection time for both exposures.

BrAC - first collection -- seconds after exposure

  • Ethanol vapor: 0.14 mg/L (0.014 mg/dL)
  • Mouth wash: 4.4 mg/L (0.44 mg/dL)


Mean time to negative BrAC level (Swedish statutory limit of 0.1 mg/L = 0.01 mg/dL in air) (FYI: US limit = 80 mg/dL)

  • Ethanol vapor: 0.5 min (0.06 - 0.7 min)
  • Mouth wash: 11 min (6 - 15 min) 



  • Ethanol vapor did not affect the BrAC
  • Mouth wash use can transiently increase BrAC; however, their use does not sufficiently increase the BrAC to result in "false positive" based upon US limit.

Show References


Numerous different household products can potentially be misused/abused. One such product is whipped cream charger/propellant that contains nitrous oxide.

Acute toxicity produce dose dependent response

  • Euphoria 
  • Anxiolysis
  • Sedation
  • Unconsciousness
  • Asphyxiation

Chronic toxicity causes myeloneuropathy (demyelination of the dorsal and lateral columns of the spinal cord) due to vitamin B12 deficiency

  • Extremity paresthesias
  • Ataxia
  • Peripheral sensory neuropathy (loss of vibration sense and proprioception)
  • Weakness 
  • Hematologic effects: leukopenia, thrombocytopenia, megaloblastic anemia


  • Cessation of nitrous oxide use
  • Vitamin B12 (cyanocobalamin) repletion (IM)

Show References

Category: Toxicology

Title: CDC alert: Vaping associated pulmonary injury

Keywords: vaping, THC, e-cigarette, pulmonary injury (PubMed Search)

Posted: 8/22/2019 by Hong Kim, MD, MPH
Click here to contact Hong Kim, MD, MPH


Center for Disease Control and Prevention (CDC) recently issued alerts regarding cases of pulmonary illnesses that may be linked to "vaping" (in 15 states with 149 possible cases). These cases are still under investigation but all cases reported vaping weeks/months prior to hospitalization.


Most cases involve young adults who have been using THC-containing products

Common complaints included

  • Gradual onset of shortness of breath, cough, and chest pain
  • GI symptoms: nausea, vomiting and diarrhea
  • Fever, fatigue


Imaging studies:

  • Chest x-ray can show bilateral opacity
  • CT lung demonstrates ground-glass opacities with sub-pleural sparing.


Clinical course

  • Some cases required mechanical intubation
  • Corticosteroid treatment appears to improve clinical course
  • Infectious evaluation was negative in almost all cases.
  • No clear causative etiology has been identified
  • No death has been reported 


What to do:

  • Inquire about vaping history when treating patients with suspected cases.
  • Providers should contact their local health department, poison center or CDC ( to report possible case of vaping associated pulmonary injury 

Show References

Category: Toxicology

Title: drug-induced liver injury and its implicated agents

Keywords: drug-induced liver injury (PubMed Search)

Posted: 8/16/2019 by Hong Kim, MD, MPH (Updated: 3/3/2024)
Click here to contact Hong Kim, MD, MPH


Direct hepatotoxicity from a drug is predictable and dose-dependent.

Most commonly implicated agents include:

  • Acetaminophen
  • Niacin
  • Aspirin
  • Cocaine
  • IV Amiodarone
  • IV methotrexate
  • Cancer chemotherapy

On the contrary, idiosyncratic prescription drug-induce liver injury is rare, unpredictable and not related to dose.

Most commonly implicated agents are:

  1. Amoxicillin-clavulanate
  2. Isoniazid
  3. Nitrofurantoin
  4. TMP-SMZ
  5. Miocycline
  6. Cefazolin
  7. Azithromycin

Bottom line:

  • Drug-induced liver injury is uncommon and can be a diagnostic challenge.
  • Recognition of commonly implicated agents can help recognize/identify drug-induced liver injury. 

Category: Toxicology

Title: How common is hematologic toxicity from copperhead bite?

Keywords: hematologic toxicity, copperhead envenomation, bleeding (PubMed Search)

Posted: 8/1/2019 by Hong Kim, MD, MPH
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Hematologic toxicity (coagulopathy/bleeding) can occur with pit viper envenomation. Copperhead is the most commonly implicated pit viper envenomation in the U.S. However, the prevalence of hematologic toxicity from copperhead envenomation is variable, possibly due to regional variation in venom potency and species misidentification. 

An observation study was performing using multi-center (Virginia Commonweath university, University of Virginia Medical Center and Eastern Virginia Medical medical center) electronic hospital/medical records (Jan 1, 2006 to Dec 31, 2016) of suspected copperhead bites. Authors state that copperhead snakes are "nearly exclusively endemic" to the VCU and UVA medical center region.



388 patients were identified but 244 met inclusion/exclusion criteria.

  • Mean age: 34 years
  • Male: 59%
  • Antivenom administration: 76%
  • No bleeding was reported.


Hematologic toxicity: 14%

  • Elevated PT: 10.0%
  • Elevated PTT: 3.9%
  • Thrombocytopenia: 1.2%
  • Hypofibrinogenemia: 0.7%



In a small sample of copperhead envenomation in Virginia, “subtle” hematologic abnormalities were observed but clinically significant hematologic toxicity was not observed (i.e. bleeding)

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