A prospective evaluation of benzocaine-associated methemoglobinemia in human beings.

Abstract

STUDY OBJECTIVE:

This study determined the frequency and severity of benzocaine-associated methemoglobinemia in routine clinical use.

DESIGN:

Prospective, crossover, convenience study.

SETTING:

Gastroenterology clinic at a US Army medical center functioning as a community hospital and tertiary referral center.

PARTICIPANTS:

Healthy adult volunteers and patient volunteers undergoing an upper gastrointestinal endoscopic procedure.

INTERVENTIONS:

Baseline methemoglobin levels were measured. Subjects then received a 2-second spray of benzocaine to the oropharynx. Venous blood for methemoglobin analysis was collected 20, 40, and 60 minutes after benzocaine dosing and analyzed using a co-oximeter.

RESULTS:

A statistically significant (P < .05) increase in methemoglobin level between baseline (0.8 +/- 0.2%) and 20-, 40-, and 60-minute measurements (0.9 +/- 0.2%) was identified using one-way analysis of variance followed by Fisher's protected least-squares difference.

CONCLUSION:

A 2-second spray of 20% benzocaine applied to the oropharynx of human beings induces a statistically significant, but clinically insignificant, increase in methemoglobin levels.

• Authors: A T Guertler, W A Pearce
• Journal: Annals of emergency medicine (Ann Emerg Med) Vol. 24 Issue 4 Pg. 626-30 (Oct 1994) ISSN: 0196-0644 [Print] United States
• PMID: 8092589 (Publication Type: Journal Article)

Chemical References

• Aerosols
• Methemoglobin
• Benzocaine

Topics

• Adult
• Aerosols
• Aged
• Aged, 80 and over
• Analysis of Variance
• Benzocaine (administration & dosage, adverse effects)
• Female
• Humans
• Least-Squares Analysis
• Male
• Methemoglobin (analysis)
• Methemoglobinemia (blood, chemically induced)
• Middle Aged
• Oropharynx
• Prospective Studies
• Time Factors