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Common Brand Name(s): NIX
This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.
This medication is used to treat head lice, tiny insects that infest and irritate your scalp. It belongs to a class of drugs known as pyrethrins. Permethrin works by paralyzing and killing lice and their eggs (nits).
Apply this medication as soon as possible after it is prescribed. When treating head lice, apply this medication to the hair and scalp only. First wash hair with your regular shampoo, but do not use conditioner. Thoroughly rinse the shampoo out with water, and towel-dry hair. Shake this medication well before using. Cover your eyes with a towel while applying this medication. Completely cover the hair and scalp with the medicine (especially behind the ears and on the hairline at the neck). Avoid getting permethrin in your nose, ears, mouth, vagina, or eyes. If the medicine gets in any of these areas, flush with plenty of water. Do not use more medication than prescribed. Leave the medication on your hair for 10 minutes or as directed by your doctor, then rinse with warm water. Towel-dry your hair and comb out any tangles. A single permethrin treatment can help prevent lice from coming back for 14 days. If eyebrows or eyelashes are infested, do not apply this medication to those areas without first consulting your doctor.
Head lice lay small white eggs (nits) at the base of hair close to the scalp, especially on the hairline at the back of the neck and behind the ears. After treatment with this medication, the infected person should be checked by another person for lice and nits using a magnifying glass and bright light. To remove nits, use the special comb provided, and follow the instructions on the package. After combing, re-check the entire head every day for nits you might have missed. Remove any nits by combing, by hand using a disposable glove, or by cutting them out. If live lice are seen 7 days or more after treatment, a second treatment with permethrin or another drug may be needed.
Tell your doctor if your condition lasts or gets worse.
Scalp irritation, including itching, swelling, or redness may occur with head lice and temporarily worsen after treatment with permethrin. Mild burning, stinging, tingling, or numbness may also occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.
Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
In the US -
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
Before using permethrin, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
Before using this medication, tell your doctor or pharmacist your medical history, especially of:
Constant or forceful scratching of the skin/scalp may lead to a bacterial skin infection. Tell your doctor right away if you develop worsening redness or pus.
Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).
Tell your doctor if you are pregnant before using this medication.
It is unknown if this drug passes into breast milk but is unlikely to harm a nursing infant. Consult your doctor before breast-feeding.
Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.
This medicine may be harmful if swallowed. If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Alberta residents can call PADIS (Poison and Drug Information Service) 24 hours a day at 1-800-332-1414. Canada residents can call a provincial poison control center.
Do not share this medication with other person unless directed to do so by your doctor.
One application is usually all that is needed. To avoid giving lice to another person or getting them again, all head wear, scarves, coats, and bed linens should be machine-washed with hot water and dried in a dryer (at high setting) for at least 20 minutes, dry cleaned, sealed in a plastic bag for 2 weeks, or sprayed with a disinfectant that kills lice. Brushes or combs should be soaked in hot water (hotter than 130 degrees F/54 degrees C) for 10 minutes, soaked in alcohol for 1 hour, or thrown away. Furniture and floors should be thoroughly vacuumed.
People who are in close contact with the infected person, such as members of the same household, should also be checked for lice and nits.
Store at room temperature. Keep all medications away from children and pets.
Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.
Information last revised October 2022.
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