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Series Editor: Mike O’Brien, PharmD

Quick evidence-based pearls on all things pharmacology and pharmacy-related in Emergency Medicine

Is Ondansetron for Nausea and Vomiting Prophylaxis Necessary with Opioids?

prophylactic ondansetron with opioids example 4+4
Ondansetron is the most documented medication given in emergency departments (ED) throughout the United States [1]. We have all heard someone ask, “Can I get an order for 4 and 4 for this patient?” in reference to 4 mg of IV morphine and 4 mg of IV ondansetron. It has become common practice in many institutions to provide a prophylactic antiemetic prior to administering an IV opioid.

Logic for giving ondansetron with opioid

This dual therapy seems to make initial sense because all opioids carry a FDA warning that nausea may occur [2]. So why not administer an antiemetic to prevent it? Opioids cause nausea and vomiting due to its interaction on the chemoreceptor trigger zone (CTZ), increased vestibular sensitivity, and hindered gastric emptying [3]. The logic is to provide these patients with a 5-HT3 antagonist (i.e., ondansetron) to inhibit the opioid from exerting emetogenic properties on 5-HT3 receptors in the CTZ and prevent nausea and/or vomiting.

How common is nausea and vomiting associated with IV opioids?

Multiple studies illustrate that morphine-induced nausea and vomiting is low, ranging from 2.0–20.2% in ED patients [4-9]. When discussing with ED nurses, nausea and vomiting are anecdotally associated with how quickly the IV opioid is administered and generally occurs within 5 minutes of administration.

So we should give IV ondansetron to prevent this, right? A common misconception with IV ondansetron is its onset of action. In fact, it can take anywhere between 27-34 minutes before there is a 50% decrease in nausea severity following the administration of ondansetron [10, 11]. This begs the question, does it really make sense to provide prophylactic antiemetics with IV opioids?

Literature Review

StudyInterventionOutcomeConclusion
Bradshaw et al. [5]

RCT- double blinded

Performed in United Kingdom

IV morphine + placebo (n=136)

IV morphine + metoclopramide 10 mg (n=123)

N/V between the 2 groups was not statistically significant (p=0.3).

Overall incidence of N/V was low in both treatment groups (3.7% in placebo and 1.6% metoclopramide)

Pre-treating patients with metoclopramide was not necessary.

Overall N/V associated with IV morphine was very low and recommended using antiemetics for patients who develop N/V.

Bhowmik et al. [8]

RCT, double blinded

Performed in India

IV morphine + placebo (n=53)

IV morphine + promethazine (n=54)

IV morphine + ramosetron (n=54)

IV morphine + metoclopramide (n=54)

Overall incidence of N/V was low in all treatment groups (9.4% ramosetron, 18.5% metoclopramide, 10.2% in promethazine and 6.2% in placebo)

Rate of N/V was not statistically significant between any of the groups.

 Patients should receive antiemetic therapy only if experience N/V and not as a prophylactic agent with IV opioids.

Patients that received (morphine + placebo) had less N/V compared to other treatment groups; however, NOT statistically significant.

Sussan et al. [9]

Randomized, double- masked multicenter trial

Performed in 9 countries

Investigated 2,574 patients that received IV opioids and randomized 520 patients that developed N/V associated with IV opioids.

Group 1: placebo (n=94)

Group 2: ondansetron 8 mg (n=214)

Group 3: ondansetron 16 mg (n=211)

Resolution of N/V was statistically more significant (p < 0.001) when comparing ondansetron therapy with placebo.

Group 1: 45.7% N/V resolved

Group 2: 62.3% N/V resolved

Group 3: 68.7% N/V resolved

The best practice seems to treat patients’ N/V after development in patients that receive IV opioids.

Trial determined the prevalence of N/V is minimal and exposing patients to medication they do not need puts them at risk for additional adverse drug reactions.

Each of the 3 trials concluded that there was no statistical significance in outcomes when adding prophylactic antiemetics with IV opioids. After these institutions analyzed their findings, the investigators at their respective institutions made it common practice for patients to only receive antiemetics AFTER a patient developed nausea or vomiting.

Prophylactic ondansetron practice

So why is ondansetron still commonly used to pre-treat patients that receive IV opioids in the ED?

The limited literature primarily focused on these anti-emetic agents: metoclopramide, promethazine, and ramosetron (5-HT3 antagonist). Literature related to specifically ondansetron is minimal.

Two randomized, placebo-controlled studies comparing ondansetron, metoclopramide, and saline in ED patients complaining of nausea showed no clinically important difference in the reduction of nausea between treatments and placebo [12, 13]. Yet in the ED, we still order ondansetron more than any other medication.

Some nerd (me!) put together a prospective multiple-site study (n=133) at 2 academic medical institutions where patients were administered IV opioids, with or without IV ondansetron [14]. Patients were observed for nausea and vomiting at baseline, 5 minutes, and 30 minutes after opioid administration, and then for a total of 2 hours. The results showed that 17.3% of patients developed nausea, with no significant difference in the rate of nausea, emesis, or the need for rescue antiemetics between the group receiving ondansetron and the group receiving opioids alone.

Of note, ondansetron is not FDA approved for the treatment or prophylaxis of acute nausea and/or vomiting (N/V) outside of chemotherapy, radiation, and postoperative use. It also, not surprisingly, has side effects!

Take Home Point

  1. Concurrent treatment with anti-emetics (including ondansetron) is unnecessary, increases costs, and adds potential for adverse drug reactions.
  2. The next time the request for “4 + 4” comes through, consider holding off on the unnecessary ondansetron with your IV opioid order.
  3. You can use this isopropyl alchohol vapor inhalation trick of the trade for those 2-20% of patients that do develop nausea.

References

  1. National Hospital Ambulatory Medical Care Survey: 2011 Emergency Department Summary. Accessed 19 Dec 2024.
  2. Red Book: pharmacy’s fundamental reference. Montvale, NJ: Thompson Healthcare Inc.; 2010
  3. Smith H, Smith J, Seidner P. Opioid-induced nausea and vomiting. Annals of Palliative Medicine 2012;1(2):121-129
  4. Paoloni R, Talbot-Stern J. Low incidence of nausea and vomiting with intravenous opioid analgesia in the ED. Am J Emerg Med 2002;20:604-608.
  5. Bradshaw M, A Sen. Use of prophylactic antiemetic with morphine in acute pain: randomized controlled trial. Emerg Med J 2006; 23:210-212.
  6. Talbot-Stern J, Paoloni R. Prophylactic metoclopramide is unnecessary with intravenous analgesia in the ED. Am J Emerg Med 2000;18(6):653-7.
  7. Lambie B, Chambers J, Herbison P. The role of prophylactic anti-emetic therapy in emergency department patients receiving intravenous morphine for musculoskeletal trauma. Emer Med 1990; 11(4): 240-243.
  8. Bhowmik A, Dasgupta I, Barua S, et al. Evaluation of the need of prophylactic antiemetic with injection morphine in treating acute musculoskeletal pain in the Indian population. IJAR 2014;2:53-58.
  9. Sussan G, Shurman J, Creed M, et al. Intravenous ondansetron for the control of opioid-induced nausea and vomiting. Clinical Therapeutic. 1999; 21:1216-1227.
  10. Cotton J, Rowell L, Hood R, et al. A comparative analysis of isopropyl alcohol and ondansetron in the treatment of postoperative nausea and vomiting from the hospital setting to the home. AANA J. 2007; 75(1):21-6.
  11. Winston A, Rinehart R, Riley G, et al. Comparison of inhaled isopropyl alcohol and intravenous ondansetron for treatment of postoperative nausea. AANA J. 2003; 71(2):127-32.
  12. Barrett TW, DiPersio DM, Jenkins CA, et al. A randomized, placebo-controlled trial of ondansetron, metoclopramide, and promethazine in adults. Am J Emerg Med. 2011 Mar;29(3):247-55.
  13. Egerton-Warburton D, Meek R, Mee MJ, et al. Antiemetic use for nausea and vomiting in adult emergency department patients: randomized controlled trial comparing ondansetron, metoclopramide, and placebo. Ann Emerg Med. 2014 Nov;64(5):526-532.
  14. Culver MA, Richards EC, Jarrell DH, et al. Use of Prophylactic Ondansetron With Intravenous Opioids in Emergency Department Patients: A Prospective Observational Pilot Study. J Emerg Med. 2017;53(5):629-634. PMID 28987314. DOI
By |2025-01-28T13:44:31-08:00Feb 26, 2025|Capsules, EM Pharmacy Pearls, PEM Pearls, Tox & Medications|
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EM Pharm Pearls: Estimated rise in blood glucose concentration with dextrose administration

A common question is how much should we expect the blood glucose concentration to increase after dextrose 50% (D50) administration. Fortunately, there is an answer from 3 studies.

  1. Balentine JR, Gaeta TJ, Kessler D, Bagiella E, Lee T. Effect of 50 milliliters of 50% dextrose in water administration on the blood sugar of euglycemic volunteers. Acad Emerg Med. 1998;5(7):691-694. doi:10.1111/j.1553-2712.1998.tb02487.x PMID 9678393
    • Population: Healthy volunteers in the ED
    • Intervention: 25 gm (1 ampule of D50)
    • Result: Mean increase of 162 mg/dL at 5 min. Glucose concentrations returned to baseline by 30 minutes.
  1. Murthy MS, Duby JJ, Parker PL, Durbin-Johnson BP, Roach DM, Louie EL. Blood glucose response to rescue dextrose in hypoglycemic, critically ill patients receiving an insulin infusion. Ann Pharmacother. 2015;49(8):892-896. doi:10.1177/1060028015585574. PMID 25986006
    • Population: Critically ill patients experiencing hypoglycemia while on insulin infusions
    • Intervention: D50
    • Result: Median increase of 4 mg/dL per gm of D50 administered
  1. Adler PM. Serum glucose changes after administration of 50% dextrose solution: pre- and in-hospital calculations. Am J Emerg Med. 1986;4(6):504-506. doi:10.1016/S0735-6757(86)80004-3. PMID 3778594
    • Population: ED patients with altered mental status (23 with diabetes, 28 without diabetes)
    • Intervention: 25 gm (50 mL of D50)
    • Result: Mean increase of 166 mg/dL

Take Home Points

  • Glucose concentrations increase 4-6 mg/dL per gm of dextrose administered
    • 50 mL of D50 = 25 gm = expected 100-150 mg/dL glucose rise
  • D50 rescue glucose is short-lived (30 minutes)
  • If the blood glucose does not respond as anticipated, investigate further (e.g., IV decannulation)

 

Want to learn more about EM Pharmacology?

Read other articles in the EM Pharm Pearls Series and find previous pearls on the PharmERToxguy site.

By |2022-07-14T18:25:07-07:00Jul 18, 2022|EM Pharmacy Pearls, Endocrine-Metabolic|
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Interpretation and Limitations of Opiate Urine Drug Tests

Background

Urine drug tests are commonly sent for patients in the emergency department, however care should be taken when interpreting the results of these tests given their limitations. The American College of Medical Toxicology published a position statement on the interpretation of urine opiate and opioid tests [1]. In this publication, they outline many of the limitations of opioid urine drug tests and explain why they exist.

Evidence

  • Though often used interchangeably, the terms opiate and opioid are not the same. ‘Opioid’ is the broad category name while ‘opiate’ simply refers to the naturally occurring opioids. The term ‘opioid’ encompasses opiates (e.g., morphine, codeine, opium), semi-synthetic agents (eg, heroin, hydrocodone, hydromorphone, oxycodone), and synthetic agents (eg, methadone, fentanyl, tramadol). Notice the name of the urine drug test next time you order one, it is likely specific for opiates (not opioids). This is because many tests are designed to identify morphine, though they will also detect codeine and heroin as they are both ultimately metabolized to morphine.
  • The standard urine drug tests do not specifically look for oxycodone, hydrocodone, etc. However, they can trigger a positive result due to their structural similarities, but not in every case. Therefore, a negative result doesn’t rule out use of these common drugs.
  • Similarly, synthetic opioids will not reliably cross-react with the opiate urine drug test as they are quite structurally dissimilar. In order to detect some of these agents, a test specific for the compound in question should be used.
  • As there are numerous different manufacturers of urine drug tests, hospitals may not utilize the same tests. In order to further understand the methods and cross-reactivity of a hospital’s specific urine drug test, the hospital’s laboratory should be contacted to request the package insert. Below is an example of the cross reactivity between various opioids with a opiate urine drug test [2].
Cross-reactivity of Various Opioids with Morphine Urine Drug Test [2]
CompoundEquivalent to 300 ng/mL Morphine (ng/mL)Cross-reactivity (%)
Codeine224134
Heroin36682
Hydrocodone1,08628
Hydromorphone1,42521
Oxycodone>75,000<0.4
Meperidine>100,000<0.3

 

Previous ALiEM posts discuss further limitations of urine drug tests, specifically for benzodiazepines and opiates.

Bottom Line

  • The term ‘opioid’ is the broad class of substances, while ‘opiate’ refers to the naturally occurring opioids (e.g., morphine, codeine)
  • Many urine drug tests are designed to identify morphine and will also detect codeine and heroin, as they are ultimately metabolized to morphine
  • Due to structural similarity, some semi-synthetic opioids may cross-react but fully synthetic opioids are unlikely to cross-react

Want to learn more about EM Pharmacology?

Read other articles in the EM Pharm Pearls Series and find previous pearls on the PharmERToxguy site.

References

  1. Stolbach A, Connors N, Nelson L, Kulig K. Acmt position statement: interpretation of urine opiate and opioid tests. J Med Toxicol. 2022;18(2):176-179. doi: 10.1007/s13181-021-00864-1. PMID: 34780053.
  2. Opiates II [package insert]. Indianapolis, IN: Roche Diagnostics; 2006.
By |2022-07-11T19:51:16-07:00Apr 23, 2022|EM Pharmacy Pearls, Tox & Medications|
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Should Diphenhydramine be included in an Acute Agitation Regimen?

Background

Acute agitation in the emergency department is a common issue that frequently requires the use of chemical sedation to preserve safety for patients and healthcare workers. A commonly employed treatment regimen is the combination of haloperidol 5 mg + lorazepam 2 mg + diphenhydramine 50 mg (B-52). Diphenhydramine is included in this treatment regimen primarily to prevent extrapyramidal symptoms [1,2]. However, the incidence of extrapyramidal symptoms (EPS) with haloperidol is quite low when treating agitation in the emergency department (ED) [3,4]. Therefore, the excessive and prolonged sedation from adding prophylactic diphenhydramine may outweigh the intended benefit and should be reserved for treatment of EPS if symptoms occur.

Evidence

Jeffers et al. conducted a multicenter, retrospective, cohort study which compared the efficacy and safety of haloperidol, lorazepam, and diphenhydramine (B-52) (n=200) vs. haloperidol and lorazepam (52) (n=200) in treating patients >18 years old with acute agitation in the ED [5]. Their primary outcome was the administration of additional agitation medication(s) within 2 hours.

Outcomes52 (n=200)B52 (n=200)p-Value
Administration of additional sedative within 2 h, n (%)40 (20)28 (14)0.11
Median ED LOS (hours)13.8170.03
Use of restraints, n (%)53 (26.5)86 (43)0.001
Hypotension, n (%)7 (3.5)32 (16)<0.001
Administration of anticholinergic within 2 days, n (%)15 (7.5%)6 (3%)0.04
    Itching/allergies, n (%)1 (0.5)1 (0.5)1.00
    Home benztropine, n (%)2 (1)4 (2)0.41
    Insomnia, n (%)4 (2)0 (0)0.06
    Unknown, n (%)8 (4)1 (0.5)0.02

 

Overall, the B-52 combination resulted in more oxygen desaturation, hypotension, physical restraint use, and longer length of stay. However, the conclusions from this study may be limited as it was a relatively small study and  it used surrogate markers to assess clinical endpoints.

Further discussion regarding the onset and duration of IM medications for acute agitation may be found in this blog post.

Bottom Line

  • The risk of extrapyramidal symptoms following haloperidol for agitation in the ED is relatively low
  • Diphenhydramine may not be necessary when using haloperidol + lorazepam to treat agitation in the ED
  • ED length of stay is increased with the addition of diphenhydramine to haloperidol + lorazepam

Want to learn more about EM Pharmacology?

Read other articles in the EM Pharm Pearls Series and find previous pearls on the PharmERToxguy site.

References

  1. Mokhtari A, Yip O, Alain J, Berthelot S. Prophylactic administration of diphenhydramine to reduce neuroleptic side effects in the acute care setting: a systematic review and meta-analysis. J Emerg Med. 2021 Feb;60(2):165–74. doi: 10.1016/j.jemermed.2020.09.031. PMID: 33131965.
  2. Vinson DR, Drotts DL. Diphenhydramine for the prevention of akathisia induced by prochlorperazine: a randomized, controlled trial. Ann Emerg Med. 2001 Feb;37(2):125–31. doi: 10.1067/mem.2001.113032. PMID: 11174228. 
  3. Klein LR, Driver BE, Miner JR, Martel ML, Hessel M, Collins JD, et al. Intramuscular midazolam, olanzapine, ziprasidone, or haloperidol for treating acute agitation in the emergency department. Ann Emerg Med. 2018 Oct;72(4):374–85. doi: 10.1016/j.annemergmed.2018.04.027. PMID: 29885904.
  4. Schneider A, Mullinax S, Hall N, Acheson A, Oliveto AH, Wilson MP. Intramuscular medication for treatment of agitation in the emergency department: A systematic review of controlled trials. Am J Emerg Med. 2021 Aug;46:193–9. doi: 10.1016/j.ajem.2020.07.013. PMID: 33071100.
  5. Jeffers T, Darling B, Edwards C, Vadiei N. Efficacy of combination haloperidol, lorazepam, and diphenhydramine vs. Combination haloperidol and lorazepam in the treatment of acute agitation: a multicenter retrospective cohort study. J Emerg Med. 2022 Mar 11;S0736-4679(22)00057-9. doi: 10.1016/j.jemermed.2022.01.009. PMID: 35287982.
By |2022-04-09T10:15:43-07:00Apr 16, 2022|EM Pharmacy Pearls, Psychiatry, Tox & Medications|
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Are Thrombolytics Safe for Acute Ischemic Strokes in Patients on DOACs?

Background

Direct-acting oral anticoagulants (DOACs), including apixaban, rivaroxaban, edoxaban, and dabigatran, are widely used for various indications and considered first-line therapy for prevention of acute ischemic stroke in patients with nonvalvular atrial fibrillation [1]. The management of acute ischemic stroke in patients on DOACs presents a difficult clinical scenario in the emergency department due to concern for increased risk of hemorrhage. IV thrombolytics (e.g., alteplase, tenecteplase), a mainstay in acute ischemic stroke management, are not recommended in current guidelines for patients whose last DOAC dose was within the last 48 hours [2, 3]. Therefore, patients with an acute ischemic stroke who are compliant with their DOACs are often excluded from guideline recommended therapy. Additionally, as covered in a previous ALiEM post, it is not recommended to reverse anticoagulation status in order to administer a thrombolytic.

Evidence

The use of IV thrombolytics in patients on DOACs was evaluated by Kam et al in a 2022 study published in JAMA [4]. This retrospective analysis included 163,038 patients from the AHA/ASA Get With The Guidelines-Stroke registry with acute ischemic stroke who received IV alteplase within 4.5 hours of symptom onset. Of the total number of patients, only 2207 had documented use of a DOAC within the last 7 days, with 25 of these patients reporting DOAC use within 48 hours. Patients on warfarin or other anticoagulants were excluded. The primary outcome was symptomatic intracranial hemorrhage (ICH) within 36 hours of IV alteplase administration. After adjusting for clinical factors, the rate of symptomatic ICH was not significantly different between patients taking DOACs and those not on anticoagulation (3.7% vs. 3.2%, adjusted OR 0.88, 95% CI 0.70 to 1.10). However, when stratified based on time from last DOAC dose, patients who took their DOAC 0-48 hours prior had an 8% rate of symptomatic ICH compared to 3.2% among those not on DOACs. Furthermore, the rate of any alteplase complication was 12% vs. 6% in those taking DOACs within 48 hours vs. no DOAC.

Limitations

  • The population at highest risk for bleeding is patients who took a DOAC within the last 48 hours, and this study only included 25 such patients.
    • A similar study tried to answer the same question for warfarin patients with an INR between 1.5-1.7. They also failed to include enough patients to make any definitive conclusions. [5]
  • Timing from the last DOAC dose was given as a range, with the majority of patients reporting use sometime within the last 7 days. It has been established in current AHA/ASA guidelines that receipt of DOACs past 48 hours prior is considered safe for thrombolytic administration, and if the included institutions were following current recommendations, thrombolytics were likely administered mostly to patients outside the 48-hour window.
  • Large potential for selection bias, since it was reported that almost 23,000 patients on DOACs from the original registry (who were otherwise eligible) did not receive thrombolytics.
  • Not clear how patients were determined to be on DOACs or if the authors were able to confirm this in unresponsive/intubated/deceased patients retrospectively. This could have resulted in DOAC patients being included in the non-DOAC group, which could have falsely evened-out the bleeding rates.

Bottom Line

  • The management of acute ischemic stroke in patients receiving prior anticoagulation presents a challenging clinical scenario.
  • Studies to date fail to include enough patients to evaluate the true risk of bleeding.
  • This study supports the current guideline recommendation to avoid alteplase in patients receiving a DOAC within 0-48 hours due to the increased risk of intracranial hemorrhage.

Want to learn more about EM Pharmacology?

Read other articles in the EM Pharm Pearls Series and find previous pearls on the PharmERToxguy site.

References

  1. January CT, Wann LS, Calkins H, et al. 2019 AHA/ACC/HRS focused update of the 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation. Published correction appears in Circulation. 2019;140(6):e285. Circulation. 2019;140(2):e125-e151. doi: 10.1161/CIR.0000000000000665. PMID: 30686041.
  2. Powers WJ, Rabinstein AA, Ackerson T, et al. Guidelines for the early management of patients with acute ischemic stroke: 2019 update to the 2018 guidelines for the early management of acute ischemic stroke: a guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke. 2019;50(12):e344-e418. doi: 10.1161/STR.0000000000000211. PMID: 31662037.
  3. Berge E, Whiteley W, Audebert H, et al. European Stroke Organisation (ESO) guidelines on intravenous thrombolysis for acute ischaemic stroke. Eur Stroke J. 2021;6(1):I-LXII. doi: 10.1177/2396987321989865. PMID: 33817340.
  4. Kam W, Holmes DN, Hernandez AF, et al. Association of Recent Use of Non-Vitamin K Antagonist Oral Anticoagulants With Intracranial Hemorrhage Among Patients With Acute Ischemic Stroke Treated With Alteplase. JAMA. 2022;327(8):760-771. doi:10.1001/jama.2022.0948. doi: 10.1001/jama.2022.0948. PMID: 35143601.
  5. Xian Y, Liang L, Smith EE, et al. Risks of intracranial hemorrhage among patients with acute ischemic stroke receiving warfarin and treated with intravenous tissue plasminogen activator. JAMA. 2012;307(24):2600-2608. doi:10.1001/jama.2012.6756. doi: 10.1001/jama.2012.6756. PMID: 22735429.

 

Primary author:

Jessica Mason, PharmD

PGY-2 Emergency Medicine Pharmacy Resident

Massachusetts General Hospital

By |2022-03-18T08:03:52-07:00Apr 2, 2022|EM Pharmacy Pearls, Heme-Oncology, Neurology, Tox & Medications, Uncategorized|
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Blood Pressure Differences in Patients with Acute Aortic Dissections

Background

An acute aortic dissection (AAD) can be a life-threatening emergency which frequently requires rapid and precise control of the patient’s heart rate and blood pressure. The 2010 guidelines for management of patients with thoracic aortic disease suggest a heart rate goal of <60 bpm and a systolic blood pressure between 100-120 mmHg. In order to achieve this, a rapid-acting beta-blocker (i.e., esmolol) may be used in combination with an IV calcium channel blocker (i.e., nicardipine or clevidipine). These medications need to be monitored closely to avoid overshooting these goals and causing hemodynamic compromise. Ideally, an arterial line would be used to monitor the patient’s blood pressure, however this may not always be feasible so a traditional, noninvasive blood pressure cuff can be used. This may be complicated if the patient has the classic, but not universal, finding of unequal systolic blood pressure values between their left and right extremities. This raises the question, in a patient with an AAD and disparate blood pressures in each arm, which arm reading should be used for monitoring?

Evidence

A 2018 study from Um et al. evaluated 111 patients with an AAD and compared them with 111 control patients. This study found that while a systolic blood pressure difference of >20 mmHg between sides was a positive predictor for an AAD, the presence of a pulse deficit had a higher diagnostic accuracy. For the purpose of this study, a pulse deficit was defined as “any recorded difference in volume/force or difference in obvious signs of malperfusion”. The cause of an unequal blood pressure or pulse deficit in the upper extremities in this population is typically due to dissection of the brachiocephalic or subclavian arteries. In order to properly achieve the desired blood pressure reduction in patients with divergent blood pressure values, the higher value should be used for titration of antihypertensives. This is due to the occurrence of pseudohypotension occurring in the limb with the dissected artery.

Bottom-line

  • Aggressive and precise heart rate and blood pressure control are critical for patients with an acute aortic dissection
  • The presence of a pulse deficit may provide better diagnostic accuracy than a difference in systolic blood pressure
  • When titrating blood pressure medications in patients with unequal blood pressure readings between extremities, the higher value should be utilized

Want to learn more about EM Pharmacology?

Read other articles in the EM Pharm Pearls Series and find previous pearls on the PharmERToxguy site.

References:

  1. Hiratzka LF, Bakris GL, Beckman JA, et al. 2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with thoracic aortic disease Circulation. 2010;121(13):e266-369. doi: 10.1161/CIR.0b013e3181d4739e. PMID: 20233780.
  2. Um SW, Ohle R, Perry JJ. Bilateral blood pressure differential as a clinical marker for acute aortic dissection in the emergency department. Emerg Med J. 2018;35(9):556-558. doi: 10.1136/emermed-2018-207499. PMID: 30021832.
By |2022-03-18T07:53:35-07:00Mar 19, 2022|Cardiovascular, EM Pharmacy Pearls|
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Extracorporeal Treatment Options in Poisoned Patients

Background

Caring for a patient that is critically-ill secondary to a toxic ingestion is complicated and, in severe cases, extracorporeal treatments (ECTRs) may be considered. The most commonly used ECTRs are intermittent hemodialysis (iHD) and continuous renal replacement therapy (CRRT), but ECTRs also include exchange transfusion, hemoperfusion, liver dialysis, and therapeutic plasma exchange. Finding and evaluating the supporting literature for these treatment modalities in a timely manner is not feasible in most situations. In order to assist in this effort, the EXtracorporeal Treatments In Poisoning (EXTRIP) workgroup has reviewed and provided free, evidence-based recommendations regarding the use of ECTRs for many common toxins and toxicants [1]. These recommendations can be found in a summarized format on the EXTRIP website and the links to their comprehensive reviews are published on PubMed with direct links on their website. This international workgroup is made up of experts in toxicology, nephrology, emergency medicine, pediatrics, pharmacology, critical care, and more. An excellent example of this resource is their review and recommendations on ECTRs for poisoning secondary to beta-adrenergic antagonists (BAAs).

Evidence

The EXTRIP workgroup included 76 publications in this comprehensive review on the use of ECTRs in BAA poisoning [2]. They evaluated pharmacokinetic/toxicokinetic data for a total of 334 patients poisoned with various BAAs, of which ~90% of the data was published prior to 1990 and does not necessarily represent the improved clearance of these medications with modern ECTR modalities. Based on this evidence, they deemed atenolol, nadolol, and sotalol as dialyzable BAAs. They also reviewed case reports/series of 37 patients with BAA toxicity and made recommendations for those agents with sufficient evidence. Based on the above data, the EXTRIP group recommends iHD over CRRT in patients severely poisoned with atenolol or sotalol and kidney impairment. They make no recommendation for or against ECTR in patients severely poisoned with atenolol or sotalol with normal kidney function and they recommend against ECTR in patients severely poisoned with propranolol.

 Bottom Line

  • Some toxic ingestions may require invasive treatment strategies (e.g., ECTRs) but a comprehensive review of the literature may not be possible
  • The EXTRIP website is an excellent resource to assess if patients should receive emergent ECTRs due to specific toxins
  • Hemodialysis is recommended in severely symptomatic patients poisoned with atenolol or sotalol and with impaired kidney function

Want to learn more about EM Pharmacology?

Read other articles in the EM Pharm Pearls Series and find previous pearls on the PharmERToxguy site.

References:

  1. Ghannoum M, Nolin TD, Lavergne V, Hoffman RS, EXTRIP workgroup. Blood purification in toxicology: nephrology’s ugly duckling. Adv Chronic Kidney Dis. 2011;18(3):160-166. doi: 10.1053/j.ackd.2011.01.008. PMID: 21531321.
  2. Bouchard J, Shepherd G, Hoffman RS, et al. Extracorporeal treatment for poisoning to beta-adrenergic antagonists: systematic review and recommendations from the EXTRIP workgroup. Crit Care. 2021;25(1):201. doi: 10.1186/s13054-021-03585-7. PMID: 34112223.
By |2022-02-02T13:49:01-08:00Feb 5, 2022|EM Pharmacy Pearls, Tox & Medications|
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