CHAPTER 2-19: ANTISEPTICS AND DISINFECTANTS

INTRODUCTION

Antiseptics are applied to living tissue to kill or prevent the growth of microorganisms. Disinfectants are applied to inanimate objects to destroy pathogenic microorganisms. Despite the lack of rigorous evidence that they prevent infection, they are used widely in households, the food industry, and hospitals. This chapter describes toxicity caused by chlorhexidine, glutaraldehyde, hexylresorcinol, hydrogen peroxide, ichthammol, and potassium permanganate. These agents are often used as dilute solutions that usually cause little or no toxicity. Hexylresorcinol is commonly found in throat lozenges. Ichthammol is found in many topical salves. Descriptions of the toxicity of other antiseptics and disinfectants appear elsewhere in this book, including the following: hypochlorite, iodine, isopropyl alcohol, mercurochrome, phenol, and pine oil (Hydrocarbons).

MECHANISM OF TOXICITY

1. Chlorhexidine is commonly found in dental rinses, mouthwashes, skin cleansers, and a variety of cosmetics. Many preparations also contain isopropyl alcohol. Systemic absorption of chlorhexidine salts is minimal. Ingestion of products with a concentration less than 0.12% is not likely to cause more than minor irritation, but higher concentrations have caused corrosive injury.

2. Glutaraldehyde (pH 3–4) is used to disinfect medical equipment, as a tissue preservative, and topically as an antifungal and is found in some x-ray solutions. It is highly irritating to the skin and respiratory tract and has caused allergic contact dermatitis with repeated exposures.

3. Hexylresorcinol is related to phenol but is much less toxic, although alcohol-based solutions have vesicant properties.

4. Hydrogen peroxide is an oxidizing agent, but it is very unstable and readily breaks down to oxygen and water. Generation of oxygen gas in closed-body cavities can potentially cause mechanical distention that results in gastric or intestinal perforation, as well as venous or arterial gas embolization. Hydrogen peroxide is found in many dental products, including mouth rinses and tooth whiteners, skin disinfectants, hair products, and earwax removers, and it has many industrial uses. In veterinary medicine it is used to induce emesis.

5. Ichthammol (ichthyol, ammonium ichthosulfonate) contains about 10% sulfur in the form of organic sulfonates and is keratolytic to tissues.

6. Potassium permanganate is an oxidant, and the crystalline form and concentrated solutions are corrosive owing to the release of potassium hydroxide when potassium permanganate comes in contact with water.

TOXIC DOSE

1. Chlorhexidine ingestions of less than 4% are expected to cause irritation, and ingestion of 150 mL of 20% solution caused esophageal damage and hepatic injury.

2. The lethal dose of glutaraldehyde is estimated to be 5–50 g/kg. Topical application of 10% solutions can cause dermatitis, and 2% solutions have caused ocular damage.

3. Hexylresorcinol is used in some antihelminthics, in doses of 400 mg (for children age 1–7 years) to 1 g (older children and adults). Most lozenges contain only about 2–4 mg.

4. Hydrogen peroxide for household use is available in 3–5% solutions and causes only mild throat and gastric irritation with ingestion of less than ...