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Anesthesia Medically Compromised Patients Supporting Your Practice

Local Anesthetics for the Patient Suffering from Methemoglobinemia


Dr. Joonyoung Ji speaks with Dr. John O’Keefe about the risks of administering local anesthetics to patients suffering from methemoglobinemia.



A patient has a scope performed in a hospital setting and benzocaine was used to numb the area before inserting the scope. Subsequently, the patient developed methemoglobinemia. The patient’s physician has now advised that all “-caine-type” anesthetics must be avoided in this patient for all dental work.


Context is important to determine why a scope was performed and how the situation that developed was managed. Often, in medical settings the amounts of local anesthetics that are used are much greater than those routinely used in dentistry. Additionally, topical agents used for scopes are used in highly vascular areas which increases the rate and amount of absorption of the anesthetic.

Graduated risks are often present and these should be discussed with the patient’s physician. The practitioner must assess all risks and benefits when managing this patient. If the patient cannot tolerate any anesthetic, then the patient can only receive preventive hygiene care.

Open and honest communication with the patient is also an important aspect of management. When appropriate especially if dental treatment with local anesthetics has been provided without issue in the past, the clinician and patient may decide to use smaller dosages of anesthetic and monitor the patient in-office for few hours post-treatment. Pulse-oximeter devices should be used and oxygen saturation should be maintained above 96-97%.



1 Comment

  1. Anonymous March 9, 2017

    Pulse oximetry is inaccurate and unreliable in patients with high methemoglobin fractions.

    Source: https://www.openanesthesia.org/methemoglobinemia_diagnosis/


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