Related Experiment Video
Updated: Jul 18, 2025

The Mouse Round-window Approach for Ototoxic Agent Delivery: A Rapid and Reliable Technique for Inducing Cochlear Cell Degeneration
Published on: November 26, 2015
Potential Toxicity of Boric Acid Powder Otic Insufflation
Samuel H Smith1, Patrick J Antonelli1
1Department of Otolaryngology, University of Florida, Gainesville, Florida, USA.
Objective:
Boric acid (BA) powder is commonly used to treat otologic conditions, such as mastoid bowl inflammation and chronic otitis externa. Exposure to 50 mg per day is thought to cause systemic toxicity in humans. Inflamed skin and mucosal surfaces readily absorb BA. The aim of this study was to measure the doses of BA commonly used in clinical otology and alert the otolaryngology community to BA's underappreciated potential source of systemic toxicity.
Study Design:
Prospective, controlled.
Setting:
Laboratory.
Methods:
BA dose administration was measured by weighing the BA generated by common insufflators: accordion bellows, House-Sheehy insufflator, DeVilbiss insufflator, and pneumatic powder blower. Manual insufflation was performed with 3 compressions of the bulb. The pneumatic blower was sprayed for 1 second. Measurements were repeated 10 times.
Results:
The DeVilbiss insufflator delivered the lowest mean BA dose, 6.1 mg (SD 3.4, range 2.1-13.7), followed by the House-Sheehy 8.9 mg (SD 8.4, range 1.6-27.8), the pneumatic blower 192.8 mg (SD 38.3, range 150.0-261.7), and the accordion, 284.1 mg (SD 215.0, range 37.8-730.8).
Conclusion:
BA dose delivery is highly variable by insufflator type, and doses thought to cause systemic toxicity are commonly generated. Awareness of and further investigation into the potential toxicity of otic administration of BA seems warranted.
Related Concept Videos
Inhalational Anesthetics: Overview
Prevention of Further Absorption of Poison
Local Anesthetics: Adverse Effects
Once absorbed into the systemic circulation, local anesthetics can affect the organs that depend on the functioning of sodium...
Upper Respiratory Drugs: Antitussives, Expectorants, and Mucolytics
Antitussives include codeine, dextromethorphan (Robitussin), and benzonatate (Tessalon). Codeine and dextromethorphan exert their effects centrally by suppressing the cough reflex center in the medulla. Benzonatate operates peripherally within the respiratory tract by...
Toxic Reactions: Overview
Toxicity falls into two primary categories: local and systemic.
Local toxicity appears at the exposure site, such as protein denaturation caused by caustic substances.
In contrast, systemic toxicity requires the toxic agent's absorption and distribution,...
Types of Toxins
Air pollutants, primarily gases, pose significant threats to respiratory health, leading to conditions like hypoxia, lung cancer, and in extreme cases, death.
Environmental pollutants like...

