NIX® Dermal Cream
Action And Clinical Pharmacology: Permethrin is a synthetic pyrethroid, which is active against a broad range of pests including lice, ticks, fleas, mites, and other arthropods. It 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.
Lag time for penetration of permethrin through the skin ranged from 1.3 to 4 hours for cis-permethrin and 2.6 to 4.8 hours for trans-permethrin. Male patients excreted more DCVA than female patients. Excretion of trans-DCVA in the urine was 4 to 5 times faster than cis-DCVA reflecting its greater concentration and more rapid rate of metabolism. Presence of esterase in skin could account for observed differences in the amount of DCVA excreted in urine of male and female patients.
There was no evidence of contact sensitization to permethrin during induction or challenge phases of maximization testing. No reactions were observed during phototoxicity testing.
Indications And Clinical Uses: For the treatment of infestation with Sarcoptes scabiei (scabies). If live mites or new lesions appear, a second treatment may be necessary 7 to 10 days after the first treatment.
Contra-Indications: Patients with known hypersensitivity to any of its components, to any synthetic pyrethroid or pyrethrin, or to chrysanthemums.
Manufacturers’ Warnings In Clinical States: If hypersensitivity to the dermal cream occurs, discontinue use.
Precautions: General: Scabies infestation is often accompanied by pruritus, edema and erythema. Treatment with permethrin may temporarily exacerbate these conditions. Pruritus caused by an acquired sensitivity to mites and their products frequently persists for one to several weeks following treatment; this reaction does not indicate treatment failure.
Information for the Patient: Patients with scabies should be advised that itching, mild burning and/or stinging may occur after application of permethrin. In clinical trials, approximately 75% of patients treated with permethrin who continued to manifest pruritus at 2 weeks had cessation by 4 weeks. If irritation persists, they should consult their physician. Permethrin may be very mildly irritating to the eyes. Patients should be advised to avoid contact with eyes during application and to flush with water immediately if the cream gets in the eyes.
Pregnancy: Teratogenic Effects: Reproduction studies have been performed in mice, rats, and rabbits (200 to 400 mg/kg/day orally) and have revealed no evidence of impaired fertility or harm to the fetus due to permethrin. There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
Lactation: It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk and because of the evidence for tumorigenic potential of permethrin in some animal species, consideration should be given to discontinuing nursing temporarily or withholding the drug while the mother is nursing.
Children: Permethrin is safe and effective in children 2 years of age and older. Safety and effectiveness in children between 2 and 23 months of age are limited. This product should therefore only be used in this age group on the advice and supervision of a physician.
Adverse Reactions: Ten percent of patients in clinical trials experienced generally mild and transient burning and stinging following application of the dermal cream. This was associated with the severity of infestation. Pruritus was reported in 7% of patients at various times post-application. Erythema, numbness, tingling and rash were reported in up to 2% of patients.
Symptoms And Treatment Of Overdose: Symptoms and Treatment: No instance of accidental ingestion has been reported. If ingested, gastric lavage and general supportive measures should be employed.
Dosage And Administration: Adults and Children over 12 Years: Approximately one 30 g tube/ 1/2 of a 60 g tube. 5 to 12 years: Approximately 1/2 of a 30 g tube/ 1/4 of a 60 g tube. 2 to 5 years: Approximately 1/4 of a 30 g tube/ 1/8 of a 60 g tube.
Usually 30 g is sufficient for an average adult. A few adults may need to use an additional 30 g.
It is recommended that family members and close contacts, including sexual partners, be treated with permethrin to reduce the risk of transmission or eliminate reinfestation.
Administration: Thoroughly massage the dermal cream into the skin from the head to the soles of the feet paying particular attention to the areas between the fingers and toes, wrists, axillae (arm pits), external genitalia (external sexual organs) and buttocks. Reapply to the hands if washed off with soap and water within 8 hours of application. It is not necessary to apply a thick visible layer of cream into the skin as it disappears on application. Scabies rarely infests the scalp of adults, although the hairline, neck, temple and forehead may be infested in geriatric patients. Children should be supervised by an adult.
The dermal cream should be removed by washing (shower or bath) after 12 to 14 hours.
In the majority of individuals, the scabies infestation is cleared with a single application of the cream. If necessary, a second application may be given 7 to 10 days after the first, but only if live mites can be demonstrated or new lesions appear.
To prevent reinfestations all clothing and bed linens used within 2 days prior to treatment should be machine-washed in hot water and dried in the dryer for at least 20 minutes, or dry cleaned.
Persistent pruritus after treatment is not an indication for retreatment (see Precautions).
Children Aged 2 to 23 Months: Children aged between 2 and 23 months should be treated only under medical supervision. The dose required is usually between 1/8 and 1/4 of a 30 g tube. The cream should be massaged thoroughly into the skin from the head to the soles of the feet, as directed for adults and older children. Infants should also be treated on the scalp, temples and forehead.
Availability And Storage: Each g of dermal cream contains: permethrin 5%. Nonmedicinal ingredients: butylated hydroxytoluene, carbomer 934P, coconut oil, glycerin, glyceryl monostearate, isopropyl myristate, lanolin alcohols, mineral oil, polyoxyethylene cetyl ethers, purified water and sodium hydroxide. Formaldehyde 1 mg (0.1%) added as preservative. Tubes of 30 and 60 g. Store between 15 and 25°C.
NIX® Dermal Cream Glaxo Wellcome Permethrin Topical Scabicide