Permethrin

Uses

Permethrin is used for the treatment of scabies.

Permethrin is also used to associated treatment for these conditions: Head Lice Infestation, Norwegian scabies, Scabies, Lice of the pubic area

How Permethrin works

Permethrin acts on the nerve cell membrane to disrupt the sodium channel current by which the polarization of the membrane is regulated. Delayed repolarization and paralysis of the pests are the consequences of this disturbance.

Dosage

Permethrin dosage

For 15 gm Tube:

• Adults and children (over 12 years): Use two full tube
• Children aged 6-12 years: Use a full tube
• Children aged 1-5 years: Use up to 1/2 of a tube
• Children aged 2 months to 1 year: Use up to 1/4 of a tube

For 30 gm Tube:

• Adults and children (over 12 years): Use a full tube
• Children aged 6-12 years: Use up to 1/2 of a tube
• Children aged 1-5 years: Use up to 1/4 of a tube
• Children aged 2 months to 1 year: Use up to 1/8 of a tube

• Patients of >2 months of age can use the dermal cream.
• Cream should be applied to clean, dry skin. If the body is hot due to warm bath or any other reason, skin should be allowed to cool.
• It should be applied to the whole body excluding head.
• The whole body should be washed thoroughly 8-12 hours after treatment.
• Adults and children above 12 years will use a 30 g tube as a single dose.
• If necessary maximum two tubes (60 gm) can be used as a single dose.
• The cream should not be applied to the vicinity of mouth and areas close to the eyes.

Side Effects

In scabies patients, skin discomfort, usually described as burning, stinging or tingling occurs in a few individuals soon after the cream is applied. Other transient signs and symptoms of irritation including erythema, edema, eczema, rash and pruritus which may follow the treatment of scabies with Permethrin are generally considered to be the 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.

Toxicity

Oral, rat LD₅₀: 430 - 4000 mg/kg; skin, rabbit LD₅₀: 2000 mg/kg.

Precaution

Permethrin is not an eye-irritant, but the cream itself may cause marked irritation. Nursing staff who routinely apply Permethrin, may wear gloves to avoid any possible irritation to the hands.

Interaction

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.

Food Interaction

Elimination Route

Poorly absorbed through the skin.

Elimination Route

Permethrin is rapidly metabolized by ester hydrolysis to inactive metabolites which are excreted primarily in the urine.

Pregnancy & Breastfeeding use

There are limited data on the use of Permethrin in pregnancy which provide no indication of any risk to the foetus. Furthermore, the amount of Permethrin absorbed systemically following a whole body application is extremely low. The negative mutagenicity tests and the very low mammalian toxicity would suggest that any risk to the foetus following treatment with Permethrin is minimal. Inspite of these, Permethrin is suggested not to useduring pregnancy.

It is not known whether Permethrin is excreted in human breast milk. So, it should not be used in nursing mothers.

Contraindication

Permethrin is contraindicated in subjects with known hypersensitivity to the product, its components, other pyrethroids or pyrethrins.

Acute Overdose

There are no reports of overdosage with Permethrin. It is possible that excessive application of Permethrin might result in localized adverse reactions or more severe skin reactions.

Storage Condition

Store at a cool and dry place. Protect from light. Do not freeze.

Innovators Monograph

You find simplified version here Permethrin