permethrin

Name: permethrin — FDA Drug Safety & Adverse Event Data
Creator: PlainMeds
License: https://creativecommons.org/publicdomain/zero/1.0/

Reviewed byPlainmeds Editorial, Drug Information Editorial Team · June 5, 2026

Verify with FDA → · CMS NADAC pricing →

Brand names: Elimite, Nix

Topical Antiparasitic OTC

Permethrin cream rinse is a medicine that kills lice and their eggs. You put it on your hair to treat head lice.

Drug Pricing (NADAC)

Generic Price

$0.23/unit

Generic Available

Yes (4 manufacturers)

Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →

View Alternatives → Compare with Another Drug → Full Side Effects Report →

What it does

This medicine treats head lice.

Common side effects

Itching, Rash, Redness

Key warnings

There are no boxed warnings for this medication.

How It Works

Permethrin works by affecting the nervous system of lice. This causes the lice to become paralyzed and die. It also kills the eggs.

How to Take It

First, wash your hair with shampoo (no conditioner). Towel dry your hair so it is damp. Shake the bottle well and put the cream rinse all over your hair and scalp. Leave it on for 10 minutes, then rinse with warm water. If you still see live lice after 7 days, use it again.

Pregnancy & Breastfeeding

It is not known if permethrin can harm an unborn baby. Talk to your doctor if you are pregnant or breastfeeding.

Missed Dose

This medication is generally only used once, so you don't have to worry about a missed dose. If live lice are seen seven days or more after the first treatment, a second treatment should be given.

Storage

Store at room temperature, between 68 to 77°F.

Side Effects (from patient reports)

Based on 1,124 FDA adverse event reports.

The medicine did not work

347

Itching

139

Using the medicine for something it's not approved for

110

Pain

Rash

Headache

Feeling sick to your stomach

Dry skin

Hair loss

Feeling worried or nervous

FDA Adverse Event Report Analysis

Detailed analysis of 1,707 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2004–2025.

Total Reports

1,707

Death-Related Reports

Hospitalization Reports

228

Top Indication

Lice Infestation

Gender Distribution

Female 975 (68%)

Male 462 (32%)

Age Distribution

0–17 156

18–44 245

45–64 354

65–74 108

75+ 102

Most Reported Adverse Reactions (FAERS)

#	Reaction	Reports
1	DRUG INEFFECTIVE	347
2	PRURITUS	139
3	OFF LABEL USE	110
4	PAIN	92
5	RASH	78
6	HEADACHE	75
7	NAUSEA	74
8	DRY SKIN	71
9	ALOPECIA	69
10	ANXIETY	69
11	CHRONIC KIDNEY DISEASE	67
12	DIARRHOEA	54
13	FATIGUE	53
14	INAPPROPRIATE SCHEDULE OF PRODUCT ADMINISTRATION	51
15	PRODUCT USE IN UNAPPROVED INDICATION	50

Reactions in Death Reports

DEATH 28

VISION BLURRED 12

FATIGUE 10

CELLULITIS 6

CONSTIPATION 6

HEADACHE 6

INCORRECT ROUTE OF PRODUCT ADMINISTRATION 6

RENAL FAILURE 6

SKIN INFECTION 6

URINARY TRACT INFECTION 6

Reactions in Hospitalization Reports

PAIN 23

DYSPNOEA 22

ACUTE KIDNEY INJURY 21

ANXIETY 19

RENAL FAILURE 18

VOMITING 17

ASTHENIA 16

CHRONIC KIDNEY DISEASE 14

PAIN IN EXTREMITY 13

HYPERTENSION 12

Source: FDA FAERS (Adverse Event Reporting System) FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation

Serious Warnings

There are no boxed warnings for this medication.

Common Questions

How do I know if I have lice?

Look for tiny nits (eggs) near the scalp, especially behind the ears and at the back of the neck. Lice and nits stick to the hair.

How do I apply the cream rinse?

Put it all over your hair and scalp after shampooing. Leave it on for 10 minutes, then rinse.

Do I need to comb out the nits?

Yes, use the special comb provided to remove nits after treatment.

What if I still see lice after treatment?

If you see live lice 7 or more days after the first treatment, use the cream rinse again.

Can I use conditioner with this medicine?

No, do not use conditioner before using the cream rinse.

How often should I check for lice after treatment?

Check the affected head daily to remove any nits that you might have missed.

Can other people in my house get lice?

Yes, all household members should be checked for lice and nits.

What should I do with the comb after using it?

Clean the comb completely as you go. Wipe the nits from the comb with a tissue and throw away the tissue in a sealed plastic bag.

Can I use this on my eyebrows or eyelashes?

No, this medication is only for use on the scalp.

What do I do if the medicine gets in my eyes?

Protect the eyes with a washcloth or towel during application. If contact occurs, rinse thoroughly with water.

What are the common side effects of permethrin?

The most commonly reported side effects of permethrin include Itching, Rash, Redness. Based on 1,124 FDA adverse event reports. Always consult your healthcare provider about potential side effects.

What drug class is permethrin?

permethrin belongs to the Topical Antiparasitic drug class. It is available over the counter (OTC). This medicine treats head lice.

Is permethrin safe during pregnancy?

It is not known if permethrin can harm an unborn baby. Talk to your doctor if you are pregnant or breastfeeding. Always consult your healthcare provider before using any medication during pregnancy or breastfeeding.

Medication Guides

Understanding Drug Interactions

How CYP450 enzymes, inhibitors, and inducers affect your medications

Generic vs Brand Name Drugs

FDA requirements, cost savings, and when the difference matters

Pain Relievers Compared

NSAIDs vs acetaminophen — which OTC pain reliever to use

Narrow Therapeutic Index Drugs

Why some drugs demand precise dosing and monitoring

Common Drug Interactions

Dangerous medication combinations and how to protect yourself

Related Health & Safety Data

🩺 Find a Doctor

Search prescribers for Topical Antiparasitic

🏨 Hospital Quality

CMS hospital ratings, safety scores & patient outcomes

💊 Supplement Data

NIH DSLD — check supplement ingredients & label claims

🍽️ Food Safety Alerts

FDA recalls, inspections & outbreak investigations

⚠️ Product Recalls

FDA, CPSC & NHTSA recall search

💉 Procedure Costs

Medicare procedure pricing for 9,297 procedures

What the FDA Data Shows for permethrin

The FDA label for permethrin (sold under brand names such as Elimite, Nix) classifies it as an over-the-counter product in the Topical Antiparasitic class. This medicine treats head lice. Official labeling lists 3 commonly reported side effects, including Itching, Rash, Redness.

Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 1,124 voluntary reports. Interaction data is drawn directly from FDA-approved prescribing information. NADAC pricing from CMS shows a generic unit cost of $0.23.

Report counts do not establish causation — a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice — always consult a licensed healthcare provider before starting, stopping, or changing any medication.

Data Sources

Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).

FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.

Last updated: November 21, 2022

Read our methodology — how this data is sourced, computed, and verified.

All federal data sources used on this page

FDA Orange Book — approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
FDA DailyMed — NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
FDA Adverse Event Reporting System (FAERS) — post-marketing safety surveillance. fda.gov/drugs/faers
NLM RxNorm — standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
CMS Medicare Part B Drug Average Sales Price Files — federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
FDA Drug Shortages Database — current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages