Poisoning due to pyrethrins.

Area of Science:

• Toxicology
• Natural Products Chemistry

Background:

• Pyrethrins are derived from chrysanthemum flower heads and possess pesticidal properties.
• They are a complex mixture of six main chemicals, often formulated with piperonyl butoxide to enhance efficacy.

Purpose of the Study:

• To review the history, mechanism of action, and toxicity profile of pyrethrins.
• To evaluate the evidence regarding pyrethrin-induced hypersensitivity and overall toxicity trends.

Main Methods:

• Literature review of historical data, clinical reports, and epidemiological studies on pyrethrin toxicity.
• Analysis of pyrethrin absorption, metabolism, and proposed mechanisms of action.

Main Results:

• Pyrethrins are rapidly metabolized and primarily act on sodium channels, causing nervous system overactivity.
• While hypersensitivity is debated, epidemiological data is largely against it. Toxicity reports have decreased, with low acute toxicity generally observed.
• Ingestion of large amounts can cause convulsions; asthma and dermatitis are reported, alongside corneal erosions from ocular exposure.

Conclusions:

• Pyrethrin toxicity is generally low, with supportive care being the primary management strategy.
• The risk of fatal hypersensitivity is not strongly supported by epidemiological evidence.
• Decreasing toxicity reports suggest improved safety or reduced exposure over time.