MHRA Drug Safety Update (March 2018): Head lice eradication products: risk of serious burns if treated hair is exposed to open flames or other sources of ignition, e.g. cigarettes

Parents, caregivers and the individual(s) with head lice, if appropriate, should be aware that some products for the eradication of head lice infestations are combustible/flammable when on the hair, and that it should be kept away from open flames or other sources of ignition, including in the morning after overnight application until hair is washed.

Dimeticone

• Cutaneous lotion 4% (£10.00 = 150ml)

Indications and dose

• Head lice:
• Adults and children aged over 6 months: Apply once weekly for 2 doses, rub into dry hair and scalp, allow to dry naturally, shampoo after minimum 8 hours (or overnight)
  • Repeat application after 7 days

Malathion

• Cutaneous aqueous liquid 0.5% (£14.31 = 150ml)

Indications and dose

• Head lice:
  • Adults and children aged over 6 months: Apply once weekly for 2 doses, rub preparation into dry hair and scalp, allow to dry naturally, remove by washing after 12 hours
    • Repeat application after 7 days
• Crab lice:
  • Adults: Apply once weekly for 2 doses, apply preparation over whole body; particular attention to hairy areas including beards and moustaches, allow to dry naturally, wash off after 12 hours or overnight
    • Repeat application after 7 days
• Scabies (second line):
  • Adults and children aged over 6 months: Apply once weekly for 2 doses, apply preparation over whole body, and wash off after 24 hours, if hands are washed with soap within 24 hours, they should be retreated
    • Repeat application after 7 days

Notes

1. One 150ml bottle should be suffice for two treatments.
2. In adults it may not be necessary to apply above the neck but children under the age of two years should have a thin film applied to the scalp, face and ears, avoiding the eyes and mouth.

Permethrin

• Cream 5% (£8.65 = 30g)

Indications and dose

• Crab lice:
  • Adults: Apply once weekly for 2 doses, apply 5% cream over whole body, allow to dry naturally and wash off after 12 hours or overnight
    • Repeat application after 7 days
• Scabies:
  • Adults and children over 2 months: Apply once weekly for 2 doses, apply 5% cream over whole body including face, neck, scalp, and ears then wash off after 8–12 hours. If hands are washed with soap within 8 hours of application, they should be retreated
    • Repeat application after 7 days

Notes

1. Larger patients may require up to two 30g packs for adequate treatment.
2. Permethrin should not be applied to broken skin, mucous membranes or near the eyes.
3. Children under 2 years should only be treated under medical supervision. Permethrin cream is not licensed for use in children aged under 2 months.
4. Permethrin is effective for scabies and crab lice. It is active against head lice but the formulation and licensed methods of application make them unsuitable for treatment.

Ivermectin

• Tablets 3mg (£55.00 = 4 tablets)

Indications and dose

• Common scabies / profuse and crusting scabies:
  • One dose (200micrograms/kg body weight) on day one; repeat the dose once after 7 days to kill recently hatched mites
  • The dose may be taken at any time of the day, but no food should be taken within two hours before or after administration, as the influence of food on absorption is unknown

Notes

1. Do not prescribe ivermectin for children who weigh less than 15kg.
2. Tablets may be crushed before swallowing.
3. Pregnancy and breastfeeding: use in pregnancy only if potential benefit outweighs risk (no adverse effects in limited human data); specialist sources indicate present in breast milk but amount probably too small to be harmful (BNF).
4. Use with caution in elderly people (SmPC).
5. Use with caution in patients who have been residents in areas where Loa loa is endemic, due to increased risk of serious adverse events (including rarely encephalopathy) in patients who are co-infected by a high number of microfilariae of Loa loa (SmPC).
6. Ivermectin potentially increases the anticoagulant effects of acenocoumarol and warfarin.