How many minutes should dichlorvos be left on for lice? - briefly
Apply the dichlorvos treatment for roughly ten minutes before rinsing thoroughly. Extending the exposure beyond this period offers no additional benefit and may increase the risk of irritation.
How many minutes should dichlorvos be left on for lice? - in detail
Dichlorvos (DDVP) is a volatile organophosphate used in some lice‑control products. Manufacturer data and regulatory guidelines specify a contact period of 5–10 minutes for effective eradication of Pediculus humanus capitis. The lower limit (5 min) is sufficient when the formulation contains the recommended concentration (typically 0.1–0.2 % active ingredient) and the product is applied evenly to the scalp and hair. Extending exposure to 10 minutes can improve efficacy against resistant nits, but it also increases the risk of skin irritation and systemic absorption.
Key points for safe application:
- Apply the solution to dry hair, ensuring full coverage from scalp to hair tips.
- Allow the product to remain on the scalp for the prescribed interval; do not rinse or shampoo before the time elapses.
- After the exposure period, rinse thoroughly with warm water and wash hair with a mild shampoo to remove residue.
- Observe for signs of irritation (burning, redness, itching). If symptoms appear, rinse immediately and seek medical advice.
- Do not exceed the maximum recommended duration; prolonged contact does not provide additional benefit and may cause toxicity.
- Use protective gloves during application to avoid dermal exposure to the hands.
- Keep the product out of reach of children; store in a cool, well‑ventilated area.
Regulatory agencies (e.g., EPA, Health Canada) advise that a single treatment followed by a repeat application after 7–10 days is sufficient to break the lice life cycle. Re‑treatment within 24 hours is unnecessary and may increase adverse effects. For individuals with sensitive skin or respiratory conditions, alternative non‑chemical treatments (wet combing, dimethicone‑based products) are recommended.