Permethrin (Elimite) Risks, Warnings, and Complications

FOR EXTERNAL USE ONLY: Permethrin is for external use on the skin and scalp only in adults and children older than 2 months of age. Do not use this medicine near the eyes or inside the nose, ears, mouth, or vagina. Do not use permethrin lotion on the eyebrows or eyelashes.

ALLERGIC REACTIONS: Seek emergency medical care if you develop an allergic reaction after using permethrin. Signs and symptoms of an allergic reaction include a severe skin rash, itching, hives, and trouble breathing. Before using permethrin, tell your doctor if you have an allergy to ragweed - permethrin can cause difficulty breathing or an asthmatic episode in people with a ragweed allergy. Call your doctor if skin or scalp irritation continues or you develop signs of infection such as pus-filled areas.

EYE PROTECTION WITH PERMETHRIN LOTION: Keep your eyes tightly closed when using permethrin lotion on the scalp and hair. Protect your eyes by covering them with a towel or washcloth. Ask another adult to apply the medicine for you. If permethrin gets into your eyes, immediately wash your eyes with large amounts of water. Call your doctor if eye irritation persists after flushing out the medicine. 

USE IN SPECIAL POPULATIONS: Permethrin is not for babies younger than 2 months of age. Check with your doctor before using permethrin If you are pregnant or breastfeeding. There is no evidence that elderly subjects respond differently to this drug compared to younger subjects. Permethrin is likely safe for use in people with impaired renal function (kidney disease) because it is excreted primarily by the liver.

PERMETHRIN TOXICITY: Animal studies have not found that permethrin causes tumors. In vitro and in vivo genetic toxicity studies have not shown a link between permethrin and mutagenesis. Also, permethrin was not found to adversely impact reproductive function or cause impaired fertility in a three-generation rat study. However, animal reproduction studies have shown an increase in lung adenomas, alveolar cell carcinomas, and benign liver adenomas in mice studies. 

The lethal dose of permethrin for humans is postulated to be 1-2 grams per kilogram of body weight. Toxicity can occur when permethrin is used as an insecticide. However, topical use of permethrin is associated with few other adverse events besides generally mild and temporary irritation of the skin. There are rare reports of toxic reactions including metabolic acidosis with excessive application of 5% permethrin cream. Neurologic effects have been reported with exposure to a pyrethroid pesticide. In case of toxicity, general supportive measures are offered because there is no antidote for permethrin.