Permethrin

The treatment of eczematous-like reactions with corticosteroids should be withheld prior to treatment with permethrin, as there is a risk of exacerbating the scabies infestation by reducing the immune response to the mite. The likelihood of interactions between the two treatments leading to potentiated adverse reactions or reduced efficacy is, however, small.

For precautionary reasons, the use of permethrin during pregnancy should be avoided unless physically acting treatment alternatives were ineffective and/or treatment with permethrin is required due to the woman’s clinical condition.

Reproduction studies have been performed in mice, rats and rabbits (200-400 mg/kg/day orally) and have revealed no evidence of impaired fertility or harm to the foetus due to permethrin. There are however, only very limited data on the use of permethrin in pregnant women.

Because animal studies are not always predictive of the human response. Treatment should be considered during pregnancy only if clearly needed.

Studies following oral administration of permethrin in cattle have indicated that very low concentrations of permethrin are excreted in milk. However, it is not known whether permethrin is excreted in human milk. Whilst it is unlikely that the concentrations of permethrin in the milk will present any risk to the infant, consideration should be given to withholding treatment during nursing or temporarily discontinuing nursing.

None known.

In scabies patients, skin discomfort, usually described as burning, stinging or tingling, occurs in a few individuals soon after permethrin dermal cream is applied. This occurs more frequently in patients with severe scabies and is usually mild and transient.

Other transient signs and symptoms of irritation, including erythema, oedema, eczema, rash and pruritus which may follow treatment of scabies with permethrin dermal cream are generally considered to be part of the natural history of scabies.

In patients treated for scabies, itching may persist for up to 4 weeks post-treatment. This is generally regarded as due to an allergic reaction to the dead mites under the skin and is not necessarily indicative of a treatment failure.

Common (≥1/100 to <1/10)
Rare (≥1/10,000 to <1/1,000)
Very rare (<1/10,000)
Not known (cannot be estimated from the available data)

Nervous system disorders

Common: Paraesthesia, skin burning sensation

Rare: Headache

Respiratory, thoracic and mediastinal disorders

Very rare: Dyspnoea (in sensitive/allergic patients)

Gastrointestinal disorders

Not known: Nausea

Skin and subcutaneous tissue disorders

Common: Pruritus, erythematous rash, dry skin

Very rare: Excoriation, folliculitis, skin hypopigmentation

Not known: Contact dermatitis, urticaria