There are no reports of overdosage with Metrin (Permethrin) Creme Rinse. On the basis of animal and human-volunteer studies, it is extremely unlikely, even with misuse or excessive application, that the amount of permethrin required to produce clinically-relevant toxic effects would be reached. The most likely symptoms and signs following repeated, excessive application would be hypersensitivity-type reactions.
Symptomatic treatment is indicated should hypersensitivity-type reactions occur.
Theoretically if swallowed by a small child, alcoholic intoxication may occur due to the isopropanol content of Metrin (Permethrin) Creme Rinse.
In the event of accidental ingestion of the contents of a bottle by a child a doctor should be consulted immediately. Gastric lavage should be considered within two hours of ingestion and management should relate to treatment of alcoholic intoxication.
Metrin (Permethrin) Creme Rinse is contra-indicated in individuals with known hypersensitivity to the product, it's components and other pyrethroids or pyrethrins.
None known.
Metrin (Permethrin) Creme Rinse is generally well-tolerated with a low potential for inducing skin reactions. In a few individuals erythema, rash and/or irritation of the scalp have been reported following the application of the creme rinse, but as an infestation with head lice is often associated with scalp irritation, it is difficult in most instances to determine the underlying cause.
If severe or prolonged signs and symptoms of scalp irritation, skin discomfort, or other undesirable effects occur in association with the use of Metrin (Permethrin) Creme Rinse it should be brought to the attention of a doctor or a pharmacist.
Reporting of suspected adverse reactions
Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard.
The active ingredient of Metrin (Permethrin) Creme Rinse is a well-known constituent of medicinal products and its safety is well documented. The results of pre- clinical studies do not add anything of relevance for therapeutic purposes.
Metrin (Permethrin) Creme Rinse is indicated for the treatment of infections with the head louse pediculus humanus capitis.
The active ingredient, permethrin, belongs to a group of medicines called pyrethroids which are anti-parasitic agents. Permethrin is rapidly absorbed across the insect cuticle. The principal physiological action is the induction of electrochemical abnormalities across the membranes of excitable cells, leading to sensory hyperexcitability, inco-ordination and prostration. When presented in aqueous base, the ovicidal activity of permethrin is increased by the addition of an alcohol.
Permethrin is rapidly metabolised by ester hydrolysis to inactive metabolites which are excreted primarily in the urine. The application of creme rinse to the hair of the volunteers for the recommended application time resulted in extremely low or undetectable level of permethrin metabolites in plasma and urine samples. In vitro studies have shown that permethrin levels on hair were not affected by chlorine in concentrations used in swimming pools.
Neither permethrin nor Metrin (Permethrin) Creme Rinse are irritants to the eyes. However, should Metrin (Permethrin) Creme Rinse be accidentally introduced into the eyes, rinse immediately with plenty of water.
Metrin (Permethrin) Creme Rinse contains methyl parahydroxybenzoate and propyl parahydroxybenzoate which may cause allergic reactions (possibly delayed).
Metrin (Permethrin) Creme Rinse contains propylene glycol which may cause skin irritation.
Metrin (Permethrin) Creme Rinse contains cetyl alcohol which may cause local skin reactions (e.g. contact dermatitis).
Nursing staff who routinely use Metrin (Permethrin) Creme Rinse may wish to wear gloves to avoid any possible irritation to the hands.
The effect of this product on artificial hair colorants and perms has not formally been studied. Although complaints are extremely rare, it is good practice to apply to a small section of hair first, before treating the entire scalp.
Children under 6 months of age should be treated on the advice of a doctor.
For external use only.
If symptoms persist consult your doctor.
Metrin (Permethrin) Creme Rinse may be used as normal in asthmatics, however contact your doctor or pharmacist before commencing treatment if you have any particular concerns.
Permethrin is not affected by chlorine in swimming baths, so normal swimming activities may continue after use.
As for other products used for the treatment of head lice, resistance can occur. After one week the result of the treatment should be checked. If living lice are still found, the treatment can be repeated with the same product. If, after 14 days, it is certain that the infestation is still active, it is best to switch to another active product.
No special comment - unlikely to have an effect.
Adults and children 6 months and over:
Topical.
Metrin (Permethrin) Creme Rinse should be used after the hair has been washed with a mild proprietary shampoo and towelled dried. The bottle should be shaken thoroughly and enough Metrin (Permethrin) Creme Rinse applied to saturate the hair and scalp. Particular attention should be given to the areas behind the ears and at the nape of the neck.
Metrin (Permethrin) Creme Rinse should be left on the hair for ten minutes before rinsing the hair thoroughly with water. The hair should then be dried in the usual way.
One bottle of Metrin (Permethrin) Creme Rinse is sufficient for shoulder length hair of average thickness. More may be applied if required and although no maximum dose has been defined, it is most unlikely that more than two bottles will be required for any one course of treatment.
It is not necessary to remove dead eggs or nits except for cosmetic purposes. A fine toothed comb may be used if desired.
Children under 6 months:
Metrin (Permethrin) Creme Rinse is not suitable for application to children under six months of age, except on the advice of a physician.
The Elderly:
Normal adult dosage is appropriate.
Shake well before use.
