
Permethrin: what it is, how it works, and how to use
Pronounced: per-METH-rin
Drug family: pyrethroid • topical pediculicide (lice treatment) • topical scabicide
Availability (U.S.): both prescription and OTC, generics widely available
Common brands: Acticin®, Elimite®, Nix®
Usual forms: permethrin 1% lotion (OTC for head lice) and permethrin cream 5% (Rx for scabies)
What does permethrin do?
Think of permethrin as a nerve switch-flipper for tiny pests. It scrambles the nerves and muscles of head lice and scabies mites, which helps kill them off. That’s why you’ll see “permethrin for scabies” on prescriptions and “permethrin for lice” on drugstore shelves.
How it’s supplied & stored
- Forms & strengths: 1% lotion (typically for scalp/lice, over-the-counter); 5% cream (typically for scabies, prescription).
- How to store: Room temp is perfect—about 68–77°F (20–25°C). Short trips in a hot/cool car are fine within 59–86°F (15–30°C). Keep it capped, dry, and out of direct sun.
When is permethrin used?
- Head lice (OTC 1% lotion): Follow the label exactly; many regimens include a second treatment after several days and careful nit-combing.
- Scabies (Rx 5% cream): Your clinician will tell you how to use permethrin cream—usually a full-body application from the neck down, left on for a set number of hours, and sometimes repeated. They may also treat close contacts and talk laundry/decontamination.
Quick note on permethrin OTC vs prescription: in the U.S., 1% lotion is non-prescription for lice; 5% cream is prescription-only for scabies.
Common side effects
Mostly local and short-lived where you apply it:
itching, burning, stinging, mild redness, irritation.
If the itch ramps up after treating scabies, that can be post-mite itch—the immune system reacting even after mites are gone. Your prescriber can coach you on soothing that.
Serious (less common) reactions—get help right away
Signs of a major allergy are a no-go:
trouble breathing or wheezing • facial/lip/tongue/throat swelling • hives or widespread rash • racing heartbeat • fever or “flu-ish” feeling • dizziness/fainting • severe stomach cramps • swollen lymph nodes • vomiting. Stop using permethrin and seek medical care.
Who should not use it?
Skip permethrin if you’re allergic to:
permethrin, pyrethrins/pyrethroids, or any inactive ingredient in your specific product (your pharmacist can read you the full list). If you’ve had reactions to similar pyrethrin products before, flag that for your clinician.
Smart-use reminders
- Use the product exactly as labeled or prescribed—amount, contact time, and repeat schedule matter.
- Don’t share your prescription cream; dosing and timing are individualized.
- For kids, a parent/caregiver should apply and rinse as directed by the clinician. Keep out of reach between uses.
- If your symptoms aren’t improving on schedule—or you’re unsure whether the permethrin cream 5% or permethrin 1% lotion routine is working—call your healthcare provider. They may adjust timing, add an anti-itch plan, or check for reinfestation.
Permethrin: real-world how-to
Only skin + hair, nowhere else. Keep permethrin on the outside: scalp, neck, and skin per directions. Don’t get it in your mouth, eyes, eyelashes, eyebrows, ears, nose, lips, or vagina. If it splashes in your eyes, flush gently with clean water. Wash hands well after each application so you don’t track the medicine to sensitive spots.
How to use permethrin
- Head lice: You’ll usually use permethrin 1% lotion (OTC). It comes in a bottle—shake well. Apply to freshly washed, towel-dried hair and scalp, behind the ears, and the nape of the neck. Leave on exactly as labeled, then rinse. Comb out nits.
- Scabies: You’ll usually use permethrin cream 5% (prescription). It comes in a tube. Apply a thin layer from the neck down (include between fingers/toes, under nails, belly button, groin, and skin folds) and leave it on for the full contact time your clinician tells you, then wash off. Kids and some adults may also need scalp/face (avoid eyes/mouth).
If you’re unsure how to use permethrin for your situation, ask your pharmacist or clinician before you start.
De-bug the environment
After treatment, handle the stuff that can hide lice/mites:
- Wash exposed bedding, clothing, hats, towels on hot water/hot dry cycle, or dry clean.
- Soak hair tools (brushes, combs, clips) in hot water.
- Items that can’t be washed can be sealed in a bag for several days.
What to expect next
- For head lice: Re-check the scalp about 1 week after using permethrin for head lice. If you still see live lice, call your healthcare provider about a second treatment. Keep nit-combing daily.
- For scabies: Itching can stick around 1–2 weeks even after mites are dead (post-mite itch). If you still see live mites after 2 weeks, your clinician may advise a second treatment.
What to tell your healthcare provider first
Lay out your full health picture and everything you take—Rx, OTC, vitamins/minerals, herbals, supplements—so they can confirm permethrin is the right fit. Flag:
- Ragweed allergy (some folks with ragweed sensitivity react to related compounds).
- Pregnancy: It isn’t clear how permethrin cream 5% or permethrin 1% lotion might affect pregnancy—tell your clinician if you’re pregnant or planning.
- Breastfeeding: It’s unknown if permethrin passes into breast milk—share if you’re nursing.
Caregivers should apply and rinse for children exactly as directed.
Food, drinks, and drug interactions
There aren’t known interactions with foods or drinks, and no well-documented drug interactions with topical permethrin. Still, keep your clinician in the loop on all meds/supplements so they can watch the whole picture.
Quick safety reminders
Use exactly as labeled or prescribed, don’t share Rx tubes, and keep out of reach of kids. If you develop significant burning, rash, or other permethrin side effects, contact your healthcare provider.
Permethrin Dosage & How-To Guide
Keep it external only. Permethrin goes on skin and hair, not in your mouth, eyes, lashes, brows, ears, nose, lips, or vagina. If it splashes in your eyes, rinse gently with clean water. Wash your hands well after you’re done.
Dosing by condition
Scabies (itchy mite rash)
- Who: Adults and kids over 2 months old.
- What: Permethrin cream 5% (prescription).
- Where & how: Apply a thin layer neck down—don’t forget behind the ears, between fingers and toes, under nails, belly button, groin, palms and soles.
- Contact time: Leave on 8–14 hours (often overnight), then rinse off.
- Repeat: Your clinician may tell you to repeat in 7–14 days.
- Note: Post-treatment itch can linger 1–2 weeks even after mites are dead.
Head lice
- What: Permethrin 1% lotion (OTC) or cream per label.
- Prep: Shampoo first and skip conditioner (conditioner makes permethrin for head lice less effective). Towel-dry to damp.
- Where & how: Saturate scalp and hair—pay extra attention behind ears and the nape.
- Contact time: Leave on 10 minutes, then rinse with warm water.
- Comb: Once hair is dry, use a fine nit comb to remove dead lice/eggs.
- Re-check: Look again about 1 week later. If you still see live lice, ask about a second treatment.
Pubic lice (“crabs”)
- What: Permethrin cream 5% (per clinician instructions).
- Where & how: Apply to pubic hair, perianal area, inner thighs down toward the knees, and any hair from the pubic line up the lower abdomen.
- Contact time: Let it dry, then keep on ~12 hours or overnight before rinsing clean.
Using permethrin the right way
- Follow the exact how to use permethrin directions from your label or prescriber—amount, coverage, and contact time matter.
- For scabies, don’t put cream on face/scalp unless your clinician says so (infants may be different).
- For lice, shorter hair can make application and nit-combing easier, but it’s optional.
Clean up the environment (key to success)
- Laundry: Wash worn clothing, pajamas, bedding, towels in hot water and hot dryer, or dry clean.
- Hair tools: Soak combs/brushes/clips in hot water.
- Items that can’t be washed can be sealed in a bag for several days. This helps prevent re-infestation while permethrin for head lice or permethrin for scabies does its job.
What to tell your healthcare provider
- Share your full med/supplement list (Rx, OTC, vitamins/minerals, herbals).
- Ragweed allergy: mention it.
- Pregnancy/Breastfeeding: safety data are limited—let your clinician guide you.
- Topical steroids: creams/ointments can mask scabies and delay recovery; your clinician may ask you to pause corticosteroids during permethrin cream 5% treatment.
Storage
Keep permethrin at room temp (about 68–77°F), in a cool, dry spot away from sunlight. Store out of children’s reach.
Side effects & safety
- Common: mild itching, redness, irritation, stinging/burning, tingling where applied—often short-lived.
- Call your clinician if symptoms are intense, worsening, or you spot pus-filled bumps.
- Stop and seek care for allergy signs: hives, swelling of lips/eyelids/face, trouble breathing, dizziness, or widespread rash.
Product (U.S.) | Form & Strength | Primary Use | Effectiveness (1–5) | Quality (1–5) | Typical U.S. Cash Price* | Notes / Best For |
---|---|---|---|---|---|---|
Nix® Creme Rinse | Permethrin 1% lotion (OTC) | Head lice (adults & kids) | 3.5–4 | 4 | $10–$20 per 2–4 oz | Widely available; use on clean, towel-dried hair for 10 min; nit-comb after. Local resistance can lower results—may need repeat in ~7–10 days. |
Store-Brand Permethrin 1% (CVS / Walgreens / Rite Aid / Equate) | Permethrin 1% lotion (OTC) | Head lice | 3.5–4 | 3.5–4 | $7–$15 per 2–4 oz | Same active as brand; good value. Pair with thorough nit-combing and household cleanup. |
Acticin® | Permethrin 5% cream (Rx) | Scabies (first-line) | 4.5–5 | 4.5 | $170–$280 per 60 g (cash) | Neck-down application 8–14 hrs, often repeat in 7–14 days. Brand pricing; insurance can lower cost. |
Elimite® | Permethrin 5% cream (Rx) | Scabies (first-line) | 4.5–5 | 4.5 | $160–$300 per 60 g (cash) | Similar to Acticin®; premium brand option. Itch may persist 1–2 weeks post-treatment. |
Generic Permethrin 5% Cream (Taro / Teva / Perrigo, etc.) | Permethrin 5% cream (Rx generic) | Scabies; pubic lice per clinician | 4.5–5 | 4.5 | $35–$120 per 60 g (cash w/ coupon); copays vary | Same active as brands; best overall value for most U.S. patients. |
Permethrin 1% Family/Value Kits (with nit comb) | Permethrin 1% lotion (OTC) | Head lice for multiple users | 3.5–4 | 4 | $18–$30 per multi-bottle kit | Economical for households; effectiveness depends on combing and retreatment timing. |
Hospital/Clinic Unit-Dose Permethrin 5% | Permethrin 5% cream packets (Rx) | Scabies (inpatient/outpatient) | 4.5–5 | 4.5 | $25–$90 per 30 g packet (cash) | Convenient single-use sizing; useful for supervised treatments or travel. |
Compounded Permethrin 5% (select pharmacies) | Permethrin 5% custom cream (Rx) | Scabies (when brands/generics unavailable) | 4.5–5 | 4–4.5 | $45–$130 per 60 g (varies by pharmacy) | Backup option; quality depends on compounding pharmacy; verify beyond-use date. |
* Cash prices are approximate U.S. retail ranges and can vary by state, pharmacy, insurance, coupons, and package size.
Permethrin — Frequently Asked Questions
Clear answers for U.S. readers about permethrin 1% (OTC) for head lice and permethrin 5% (Rx) for scabies.