Permethrin

Written by Jennifer Seabright, PharmD
Medically reviewed by Melissa Badowski, PharmD, MPH, FCCP
Updated on June 28, 2023

This article describes permethrin’s uses, side effects, and more. You’ll also find some coupon options to help save on the cost of permethrin.

Below you’ll find answers to a few commonly asked questions about permethrin.

Is it safe to use permethrin on your clothes?

This article discusses permethrin cream, which is not approved to use on clothes. There are other products containing permethrin that you may use on clothing. Talk with your doctor to learn more about these products.

Can permethrin be used for ticks, bed bugs, or mosquitoes?

No, permethrin cream is not approved to be used for ticks, bed bugs, or mosquitoes. It’s only approved to treat scabies. To repel insects, you’ll need to use an insect repellent, which may involve spraying your yard.

For more information about permethrin’s approved uses, talk with your doctor.

Is it safe for dogs or cats to use permethrin?

Permethrin cream is approved for use in humans. If you have questions about applying permethrin cream on your dog or cat, talk with your veterinarian. Do not administer permethrin or any other medications to a pet before talking with your veterinarian.

How does permethrin work? And how long does it take to start working?

Permethrin works by damaging the nerve cells of the pests that cause scabies. It starts working soon after you apply the cream to your skin. The treatment finishes working after 8–14 hours. Usually, one round of permethrin treatment clears up scabies.

If you’d like to know more about this, talk with your doctor or pharmacist.

The Food and Drug Administration (FDA) approves prescription drugs such as permethrin for certain conditions. Approved uses for permethrin are described below.

Use for scabies

Doctors may prescribe permethrin cream for treating scabies. It’s used for this purpose in adults and children ages 2 months and older. It’s usually prescribed as a one-time treatment.

With scabies, mites burrow under the skin and lay their eggs. Scabies spreads in crowded living spaces through prolonged skin-to-skin contact with a person who has it. Symptoms of scabies include:

• a pimple-like rash that may have blisters or scales
• intense itching that may be worse at night
• tiny, crooked lines on the surface of skin
• mites under the skin between fingers, wrists, and elbows

It may take up to 8 weeks for scabies symptoms to show up in a person who’s never had it before. For people who’ve had scabies in the past, symptoms usually show up within 4 days.

Doctors may not prescribe permethrin cream for people who are allergic to permethrin or related drugs.

Permethrin may cause mild or serious side effects. More common mild side effects of permethrin and its serious side effects are listed below. This article doesn’t include all possible side effects of the drug. Side effects can vary based on your age, overall health, and any other medications you take.

To learn more about permethrin’s side effects, ask your doctor or pharmacist. You can also refer to the prescribing information for permethrin listed in the “Article resources” section.

Mild side effects

More common mild side effects reported with some forms of permethrin are listed below.

This article doesn’t include all possible mild side effects of the drug. To learn more about permethrin’s side effects based on the form, refer to the prescribing information for permethrin listed in the “Article resources” section.

With many drugs, mild side effects may go away within a few days or a couple of weeks. If the side effects are bothersome, tell your doctor or pharmacist. They may be able to suggest ways to manage them.

Permethrin topical cream’s mild side effects include:

• burning
• stinging
• itching
• redness or discoloration
• mild allergic reaction*

* For details about this side effect, see the “Interactions and warnings for permethrin” section.

Serious side effects

Serious side effects of permethrin are listed below.

This article doesn’t include all possible serious side effects of the drug. To learn more about permethrin’s side effects based on the form, refer to the prescribing information for permethrin listed in the “Article resources” section.

With many drugs, serious side effects are possible but not common. If you have serious side effects from this drug, call your doctor right away. If you’re having severe symptoms or a medical emergency, call 911 or a local emergency number.

In general, permethrin’s only serious side effect is severe allergic reaction. For details about this side effect, see the “Interactions and warnings for permethrin” section.

Below, you’ll find information about permethrin’s possible interactions and warnings.

Interactions of permethrin

Permethrin isn’t known to interact with any medications or supplements. (Interactions can affect how a drug works.) But this doesn’t mean drug interactions with permethrin won’t happen or be reported sometimes. For instance, medications created at a later time could interact with permethrin.

Because of this, you should ask your doctor and pharmacist about possible interactions with permethrin. They can check for any interactions that may affect you, such as those with:

• vaccines
• foods or alcohol
• other drugs

Warnings for permethrin

Permethrin should not be used by certain people.

Permethrin could cause harm to people with certain health conditions. This effect is called a drug-condition interaction. Other factors can also affect whether permethrin is a safe option for you.

Ask your doctor about specific warnings for permethrin, and be sure to tell your doctor about your:

• current health, including any allergies to medications
• past health conditions or surgeries

Allergic reaction

Permethrin can cause an allergic reaction in some people. Severe allergic reactions are rare but possible.

If you’ve had an allergic reaction to permethrin or any of its ingredients, your doctor will likely not prescribe permethrin. They can tell you about medications that are safer options for you.

A mild allergic reaction may cause the following symptoms:

• skin rash
• itchiness
• flushing (temporary warmth, redness, or deepening of skin color)

A severe allergic reaction may cause the following symptoms:

• swelling under your skin, usually in your hands, feet, eyelids, or lips
• swelling of your mouth, throat, or tongue, which can cause breathing problems

If you have an allergic reaction to permethrin, call your doctor right away. If you have severe symptoms, call 911 or a local emergency number.

Overdose of permethrin

If you apply permethrin, you should not use more permethrin than your doctor prescribes. For some drugs, doing so may lead to harmful effects or overdose.

If you think you’ve used too much permethrin, call your doctor or pharmacist right away. Or you could call 800-222-1222 to speak with someone at America’s Poison Centers. You can also use its online resource. If you have concerning symptoms, call 911 or a local emergency number immediately. You can also go to the closest emergency room.

Pregnancy or breastfeeding and permethrin

Information about permethrin and pregnancy and breastfeeding is described below.

Permethrin and pregnancy

There are risks to using permethrin during pregnancy. But there are also risks with having untreated scabies while pregnant. (Keep in mind that permethrin is used for treating scabies.)

If you’re planning a pregnancy or can become pregnant, talk with your doctor about scabies treatment options during pregnancy. Together, you can discuss the risks and benefits of your treatment options and decide whether or not you should use permethrin during pregnancy.

Permethrin and breastfeeding

It’s not known whether permethrin should be used while breastfeeding. If you’re currently breastfeeding or planning to do so, talk with your doctor before using this medication.

This article describes permethrin’s uses and side effects, ways to save on cost, and more. Let your doctor know if you have questions about permethrin or would like more details about it.

Here’s a list of some possible questions you may want to ask your doctor:

• Are there any alternative medications I can use for scabies?
• What are my options if I can’t afford my medication?
• What factors might increase my risk for side effects?

• Food and Drug Administration. (2023). Orange Book: Approved drug products with therapeutic equivalence evaluations. https://www.accessdata.fda.gov/scripts/cder/ob/index.cfm
• Permethrin — permethrin cream. (2023). https://nctr-crs.fda.gov/fdalabel/services/spl/set-ids/041444b6-a71e-4d13-8d24-f2d104bf721d/spl-doc
• Scabies frequently asked questions (FAQs). (2020). https://www.cdc.gov/parasites/scabies/gen_info/faqs.html

Disclaimer: Optum Perks has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.