UMEM Educational Pearls - Toxicology

Title: Had enough of coumadin and clopidogrel wannabe's?

Category: Toxicology

Keywords: ticagrelor, brillinta, xarelto, pradaxa (PubMed Search)

Posted: 3/15/2012 by Fermin Barrueto (Updated: 1/27/2026)
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Coumadin Wannabe's - have indication non-valvular atrial fibrillation

1) Dabigatran (Pradaxa) 

2) Rivaroxaban (Xarelto)

Clopidogrel Wannabe's - both are antiplatelets

1) Ticagrelor (Brilinta)

2) Prasugrel (Effient)

If you were looking for the first case reports of lethal hemorrhage due to pradaxa that could not be reversed - look no further. One patient fall from standing dies from ICH and another death in a spine trauma patient on pradaxa. I am waiting for the first epidural hematoma due to pradaxa, xarelto, etc in ED. Watch out! :

 

  1: Garber ST, Sivakumar W, Schmidt RH. Neurosurgical complications of direct  thrombin inhibitors-catastrophic hemorrhage after mild traumatic brain injury in  a patient receiving dabigatran. J Neurosurg. 2012 Mar 6.       2: Truumees E, Gaudu T, Dieterichs C, Geck M, Stokes J. Epidural Hematoma &  Intra-operative Hemorrhage in a Spine Trauma Patient on Pradaxa® [Dabigatran].  Spine (Phila Pa 1976). 2012 Feb 16. 

 



Title: Pressure Immobilization for Crotalid snake envenomation

Category: Toxicology

Keywords: crotalinae, snake, pressure immobilization, envenomation (PubMed Search)

Posted: 3/4/2012 by Bryan Hayes, PharmD (Updated: 3/8/2012)
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Pressure immobilization involves wrapping the entire extremity with a bandage and then immobilizing the extremity with a splint. It is a technique routinely employed in the pre-hospital management of neurotoxic snakes in Australia.

A position statement was recently published by several international toxicology societies regarding the utility of pressure immobilization after North American Crotalinae snake envenomation (e.g., Copperheads, Timber rattlesnakes, Cottonmouths).

"Available evidence fails to establish the efficacy of pressure immobilization in humans, but indicates the possibility of serious adverse events arising from its use. The use of pressure immobilization for the pre-hospital treatment of North American Crotalinae envenomation is NOT recommended."

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Title: Octreotide for sulfonylurea overdose- updated

Category: Toxicology

Keywords: Octreotide, sulfonylurea, glucose, insulin (PubMed Search)

Posted: 3/1/2012 by Ellen Lemkin, MD, PharmD
Click here to contact Ellen Lemkin, MD, PharmD

 

  • Sulfonyurea overdose is associated with hypoglycemia, which may be delayed and prolonged.
  • Treatment with dextrose results in hyperglycemia, which potentiates insulin release from the pancreas, resulting in recurrent hypoglycemia.
  • Octreotide mimics somatostatin, which suppresses the secretion of glucagon and insulin, among others.
  • Octreotide binds with somatostatin receptors, closing calcium channels, preventing the influx of calcium and subsequent insulin release.
  • The dose is 100 mcg SUBCUTANEOUSLY, repeated every 8 hours as needed.

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Title: IM Midazolam vs IV Lorazepam for Seizure Pre-Hospital

Category: Toxicology

Keywords: midazolam, lorazepam (PubMed Search)

Posted: 2/23/2012 by Fermin Barrueto (Updated: 1/27/2026)
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You have seen the study comparing diazepam to lorazepam IV for the cessation of seizures. Lorazepam one that one. Now, for prehospital status epilepticus midazolam IM went head to head with IV lorazepam to see which would stop seizure more quickly.

This study was more about the practicality of starting an IV than it was of the pharmacokinetics or onset of action of a particular benzodiazepine. It was a large enough study to warrant publication in New Engl J Med last month and is worth noting.

Subjects whose seizures ceased before ED arrival (median):

Time to active treatment: 1.2 min IM Midazolam group;  4.8 min IV Lorazepam group

Median times active treatment to cessation of SZ:  3.3 min IM Midazolam and 1.6 min IV Lorazepam

Safety was equal in both groups. This study validates EMS initiating therapy with IM midazolam for the cessation of seizures while intravenous access is being attempted. 

 

 

 

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Title: Drug Rash with Eosinophilia and Systemic Symptoms (DRESS)

Category: Toxicology

Keywords: DRESS, anticonvulsant, eosinophilia, phenytoin, carbamazepine (PubMed Search)

Posted: 2/7/2012 by Bryan Hayes, PharmD (Updated: 2/19/2012)
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  • Drug rash with eosinophilia and systemic symptoms (DRESS) syndrome, previously named “anticonvulsant hypersensitivity syndrome,” is a severe adverse drug reaction which occurs in approximately 1 of every 1,000–10,000 uses of anticonvulsants.

  • Characterized by triad of fever, rash, and internal organ involvement.

  • Usually involves aromatic anticonvulsants such as phenytoin, carbamazepine, phenobarbital, primidone, lamotrigine, and possibly oxcarbazepine.

  • DRESS occurs most frequently within the first 2 months of therapy and is not related to dose or serum concentration.

  • Treatment includes prompt discontinuation of the offending agent. Patients should be admitted to the hospital and receive methylprednisolone 0.5–1 mg/kg/d divided in four doses. Other promising therapies include use of IVIG.

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Title: Succinylcholine

Category: Toxicology

Keywords: paralytic, hyperkalemia, succinylcholine (PubMed Search)

Posted: 1/26/2012 by Fermin Barrueto (Updated: 1/27/2026)
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As we go through the problems of national drug shortages it is important to remember the old drugs but to also remember why they became old and seldom used drugs. Prime example is many hospitals are beginning to develop shortages of rocuronium - the nondepolarizing paralytic that has a fast onset. This shortage has caused many to switch back to succinylcholine. The following case report should serve as reminder of how succinylcholine - due to its depolarizing nature and fasciculations - can cause a transient but significant hyperkalemia.

 

 

Succinylcholine-induced Hyperkalemia in a Patient with Multiple Sclerosis 
The Journal of Emergency Medicine, 12/13/2011

Levine M et al. – This case report describes a 38–year–old woman with multiple sclerosis who developed life–threatening hyperkalemia after the administration of succinylcholine during rapid sequence intubation. This case highlights the potential for iatrogenic hyperkalemia after succinylcholine in patients with neurologic diseases, including multiple sclerosis.






Title: Pradaxa - Watch out

Category: Toxicology

Keywords: pradaxa, myocardial infarction (PubMed Search)

Posted: 1/19/2012 by Fermin Barrueto (Updated: 1/27/2026)
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Never be the first or last person to use a drug 

Vioxx was once touted to be the drug that would be the new standard for anti-inflammatories until it was found to increase your chance of MI by 33% and cause hypertension.

Dabigatran was recently pulled from Japan markets and now is dealing with an impressive meta-analysis by Uchino et al. It showed that dabigatran was significantly associated with higher risk of MI or ACS than other agents.

Control arms (included warfarin, enoxaparin or placebo): MI rate 83 per 10,514

Dabigatran arms: MI rate 237 per 20,000

OR 1.33; 95% CI, 1.03-1.71; p=0.03

The rush for what is perceived as a panaceae for all that is wrong with coumadin could actually cause an MI while it tries to prevent a stroke in nonvalvular a-fib.

Look at the study and decide for yourself and remember Vioxx:

http://archinte.ama-assn.org/cgi/content/full/archinternmed.2011.1666v1



Title: Buprenorphine Poisoning in Children (submitted by Ashley Strobel, MD)

Category: Toxicology

Keywords: buprenorphine, Suboxone, overdose, children (PubMed Search)

Posted: 1/10/2012 by Bryan Hayes, PharmD (Updated: 1/12/2012)
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  • Suboxone = buprenorphine and naloxone in a 4:1 ratio, respectively. Formulated in 2 mg or 8mg tablets and film.

  • Buprenorphine acts as a partial agonist on the mu receptor and an antagonist at the kappa receptor.

  • If > 2 mg are ingested or age < 2 years old, these patients should be evaluated in an ED as ALL children with > 4 mg ingestion had symptoms.

  • There is a ceiling effect with respiratory depression however no ceiling with analgesia. This gives buprenorphine a better safety profile compared to methadone.

  • Onset of symptoms is about an hour and onset of respiratory depression is about 2-3 hours.

  • Increased doses of naloxone starting at 0.1 mg/kg may be needed to overcome high receptor affinity of buprenorphine. Remember, most children are opioid-naive and will not experience withdrawal symptoms. Repeat doses of naloxone and even infusions may be needed.

  • In the ED, a minimum of 6 hours observation is necessary. If no clinical effects are noted at 6 hours the patient can safely be discharged, although one small case series recommended 24 hours observation.

  • Unintentional overdose is common in toddlers, so advise family to keep prescriptions including family pet prescriptions locked (buprenorphine in the IV form is used for veterinary pain control).

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Title: Rivaroxaban (Xarelto) - Another Pradaxa?

Category: Toxicology

Keywords: pradaxa, xarelto (PubMed Search)

Posted: 12/29/2011 by Fermin Barrueto (Updated: 1/27/2026)
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Another great example of the generic drug name being so difficult to pronounce you have no choice but to say - Xarelto. The drug touts ease of use and no need for hematologic monitoring like Pradaxa. This drug has the same indication for stroke prevention in nonvalvular atrial fibrillation. It also is being used in DVT prophylaxis in hip and knee surgeries.

Differences:

- Selective Factor Xa inhibitor unlike Pradaxa which is a competetive direct thrombin inhibitor

- Once a day dosing instead of twice a day for Pradaxa

Same concerns:

- No real reversal but can use FFP in a pinch

- Recommend waiting 24 hrs DC med to perform surgical procedure - this includes LP. I am personally waiting for the first case report of LP performed in ED on a patient taking either Xarelto or Pradaxa with subsequent epidural hematoma. Someone is bound to miss this on the med list. Be careful.

Even if your hospital has not added it to its formulary, you will see patients on this drug in the ED.



Title: Hydrogen Peroxide

Category: Toxicology

Keywords: hydrogen peroxide (PubMed Search)

Posted: 12/22/2011 by Fermin Barrueto (Updated: 1/27/2026)
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Generally H2O2 is available OTC at a concentration of 3-9% and used as an antiseptic. Toxicity is by two methods: local irritation like a caustic and gas formation - both directly correlating with the % concentration. Some interesting findings have occurred with this ingestion including:

1) Portal vein gas seen on CT

2) Arterialization of O2 resulting in CVA

3) Encephalopathy with cortical visual impairment

4) MRI showing b/l hemispheric CVAs

Even use of 3% H2O2 for wound irrgation has caused subcutaneous emphysema and O2 emboli.

Treatment: XR/CT/MRI may detect gas, if present in RV should be placed in Tredelenburg and carefully aspirated through a central venous catheter. Anectdotal case reports have used HBO therapy when patients were critically ill.(1)

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Title: Warfarin management of ED patients

Category: Toxicology

Keywords: warfarin, INR (PubMed Search)

Posted: 11/29/2011 by Bryan Hayes, PharmD (Updated: 12/8/2011)
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A recent study highlighted the challenges we face managing ED patients on warfarin therapy. Some key observations about how we're doing: 

  • Only 71% of patients on warfarin had an INR checked
  • Nontherapeutic INRs were recorded for 49%; ED providers intervened to address these results in 21% of cases
  • 71% of patients with a supratherapeutic INR received an intervention compared with 9% of patients with a subtherapeutic INR
  • 30% of patients received or were prescribed potentially interacting medications
  • Recommendations for specific anticoagulation follow-up were documented for only 19% of all patients

Literature continues to show warfarin is the most dangerous medication for our patients. Meticulous monitoring and follow up will help us potentially avoid serious interactions and adverse events.

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Title: High dose insulin in cardiogenic shock

Category: Toxicology

Keywords: Insulin,beta blockers,calcium channel blockers (PubMed Search)

Posted: 12/1/2011 by Ellen Lemkin, MD, PharmD
Click here to contact Ellen Lemkin, MD, PharmD

High dose insulin is recommended in treatment of beta-blocker and calcium channel blocker overdose. In a recent observational case series of cardiogenic shock, high dose insulin was evaluated for efficacy and safety.

 
The overdoses were primarily calcium channel and beta blockers, but included other agents
like tricyclic antidepressants.
  • Insulin doses were given at a maximum of 10 units/kg/hour.
  • Seven patients who were on vasopressors when enrolled were tapered off when placed on high dose insulin.
  • 11/12 patients lived and were discharged from the hospital.
  • Adverse effects included hypoglycemia (19 events) and hypokalemia (8).
Bottom line: High dose insulin, when used in doses up to 10 units/kg/hr allows avoidance of vasopressors, and appears to be effective in the treatment of toxin induced shock in this small case series.

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Title: Toxic Epidermal Necrolysis

Category: Toxicology

Keywords: Toxic, epidermal, necrolysis (PubMed Search)

Posted: 11/17/2011 by Fermin Barrueto
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TEN is a rare, life-threatening dermatologic emergency characterized initially by erythema and tenderness. It is followed by a severe exfoliation that resembles a severe burn patient. Classically occurs within days of the exposure of the drug. Nikolsky's sign may be present - not pathognomonic.

The following is a short list of medications that can cause this lethal reaction:

allopurinol, bactrim, nitrofurantoin, NSAIDs, penicillin, phenytoin, lamotrigine, sulfasalazine

Treatment: transfer to a burn center may be needed, steroids are not generally recommended however immunomodulators are beginning to show promise - IVIG, cyclosporine and cyclophosphamide

 

See pic that is attached for example of the sloughing

Attachments



Title: Medication Causes of Idiopathic Intracranial Hypertension

Category: Toxicology

Keywords: idiopathic intracranial hypertension, pseudotumor cerebri, tetracycline, vitamin a (PubMed Search)

Posted: 10/11/2011 by Bryan Hayes, PharmD (Updated: 11/10/2011)
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Several medications have been linked to causing idiopathic intracranial hypertension (pseudotumor cerebri). Be sure to record an accurate medication history in patients you suspect of having this diagnosis.

  • Excessive doses of vitamin A
    • Other retinoids too: retinol, isotretinoin, and tretinoin
  • Tetracyclines (tetracycline, doxycycline, minocycline)
  • Growth hormone

Withdrawal of the offending agent will generally resolve the symptoms.



Title: Salicylate Toxicity- Mechanism

Category: Toxicology

Keywords: salicylate, aspirin, alkalosis, acidosis (PubMed Search)

Posted: 11/3/2011 by Ellen Lemkin, MD, PharmD (Updated: 1/27/2026)
Click here to contact Ellen Lemkin, MD, PharmD

Salicylates:

  • stimulate the respiratory center in the brainstem, causing respiratory alkalosis
  • interfere with the Krebs cycle, limiting ATP production, leading to an anaerobic metabolism
  • uncouple oxidative phosphorylation, causing accumulation of pyruvic and lactic acid and heat production, resulting in acidosis and hyperthermia
  • increase fatty acid metabolism, generating ketone bodies

Overall, this results in a mixed respiratory alkalosis and metabolic acidosis. 

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Title: Methotrexate

Category: Toxicology

Keywords: overdose, methotrexate (PubMed Search)

Posted: 10/27/2011 by Fermin Barrueto (Updated: 1/27/2026)
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Methotrexate is a chemotherapeutic that is utilized in non-Hodgkin lymphoma and breast CA. It is also used as an immunosuppressant for rheumatoid arthritis and psoriasis. Finally, we see it used in the ED for the treatment of ectopic pregnancy. Overdose, often unintentional, can have a lethal outcome.

Toxicity: LFTs rise, N/V, stomatitis, mucositis, leukopenia, thrombocytopenia, renal failure

Antidote: Leukovorin (Folinic Acid)

Other Tx: Carboxypeptidase G2, Charcoal Hemoperfusion, HD (possible)



Carbon Monoxide Toxicity and Hyperbaric Oxygen Treatment

CO disrupts cellular function by several mechanisms at a
cellular/mitochondrial level.  Ultimately, these disruptions are
manifested as tissue hypoxia and hypoperfusion.
Initial symptoms may be subtle and nonspecific.  Be sure to ask about
CO exposure when evaluating “viral syndrome” or patients that present
with non-specific neurological complaints especially during fall and
winter months, when people first start using their heating, or after
power outages and generator use. Dysrhythmias, cardiomopathy, MI and
sudden cardiac arrest are reported in severe CO poisoning.

Lab studies- COHb, base excess, lactate and any other studies based on
presentation.

Supplemental oxygen is the cornerstone of treatment.   Oxygen
delivered at hyperbaric pressure (as opposed to sea-level) will
increase the rate of CO dissociation from hemoglobin, and mitigate
damage to cellular and mitochondrial function.

Definite Indications for HBOT:  Current evidence supports the use for
HBOT to reduce cognitive sequelae in CO poisoned patients who have:
LOC , seizure, exposure >23 hours, COHb of 25% or more, and age >36.
Relative Indications:  persistent symptoms after 100% O2 or change in
mental status, pregnancy, persistent cardiac ischemia, increased COHb
levels.

 Disposition:  Clinical judgment should guide your decision.  Most
patients with mild symptoms can be discharged after treatment. If
patient has a more concerning presentation with several risk factors
(extremes of age, CAD, unconscious at arrival in the ED, etc…)
consider admission.



Title: ED Pharmacist

Category: Toxicology

Keywords: toxicology, pharmacist (PubMed Search)

Posted: 9/29/2011 by Fermin Barrueto (Updated: 1/27/2026)
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A growing trend in EDs is to have a dedicated ED Pharmacist present to assist with the evaluation of a patient's medication list, appropriate and safe drug administration and to improve drug delivery times. To date, it has been difficult for hospitals to determine if this was a cost-effective measure. There has been increasing research that has shown the proven benefits that physicians feel when they have an ED Pharmacist. With the aging population, increasing polypharmacy, core measure and national patient safety goals all rising to the top of hospital initiatives, the ED pharmacist will be proven to be a valuable cog of the ED - as UofMd already knows

1) Improved safety - this study showed an ED pharmacist caught 2.9 errors/100 medications, very important considering the cost of just one severe reaction can cause a hospitalization or even litigation(1)

2) Improved time to delivery of medication - this study showed improved time of delivery of medications not found in a Pyxis from 61 min with no pharmacist  decreased  to 47 min with ED pharmacist.(2)

Further studies will be needed to determine the true cost:benefit however with core measures like 6hr time to administration of antibiotics and the safe/timely adminstration of tPA combined with patient safety/quality goals - the value of an ED pharmacist will only be accentuated.

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Title: Adenosine in Patients with Only Central Line Access

Category: Toxicology

Keywords: adenosine, central line (PubMed Search)

Posted: 8/29/2011 by Bryan Hayes, PharmD (Updated: 9/8/2011)
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Every so often a patient arrives in PSVT with their only intravenous access being through a hemodialysis port.

Initial dose of adenosine should be reduced to 3 mg if administered through a central line.  Remember a central line delivers the adenosine right where you need it.  This recommendation is supported by the 2010 ACLS guidelines.  Second and third doses should be 6 mg (instead of 12 mg).

Cases of prolonged bradycardia and severe side effects have been reported after full-dose adenosine through a central line.  Other situations to consider lower doses include patients currently receiving carbamazepine or dipyridamole or in those with a transplanted heart.

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End Tidal CO2 continuous capnography is being utilized more in the ED for procedural sedation. One of the best studies is a randomized control trial using propofol that showed you could see signs of hypoventiliation prior to hypoxia by about 60 seconds - which can be plenty of time to get your BVM and airway cart ready.

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