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Important Note

The following information is intended to supplement, not substitute for, the expertise and judgment of your physician, pharmacist or other healthcare professional. It should not be construed to indicate that use of the drug is safe, appropriate, or effective for you. Consult your healthcare professional before using this drug.


(pie-RETH-rins WITH pip-ER-oh-nill)

COMMON BRAND NAME(S): Medi-Lice, Pyrin-X, Pyrinyl II, Tisit


This medication is used to treat current and active lice infestations. It is not used to prevent future lice infestations.

How To Use

Review the manufacturer's instruction sheet with your doctor or pharmacist and follow all directions carefully for your product. All household members and/or those in close contact with you should be checked for infestation and treated if infected. This medication is for external use only. Avoid applying drug to the eyes, nose, mouth or vagina. Do not use on eyelashes or eyebrows. Check with MD if these areas are infested. Do not use more drug than is recommended. If applying to infants, cover their hands and feet after applying the drug to insure they do not ingest the medicine. Apply in a well-ventilated area. Apply to the skin once, thoroughly covering the affected area. Leave on for about 10 minutes unless directed otherwise by your doctor. Then wash the affected area with warm water and soap. Rinse and dry with a clean towel. For hairy areas, use nit removal comb as directed. Wash hands immediately after use. Repeat the application once seven to ten days later to kill any newly hatched lice. Be sure to follow instructions on proper machine washing of clothing, bedding, etc., special house cleaning, plus comb and wig/hairpiece cleaning.

Side Effects

Unlikely but report skin rash, sneezing/stuffy nose, trouble breathing, skin infection or irritation not present before starting this medication. If you notice other effects not listed above, contact your doctor or pharmacist.


Before using this drug, tell your doctor your medical history, including: any drug allergies, ragweed allergy, allergies to chrysanthemum plants or kerosene, skin problems. This drug is harmful if swallowed or inhaled. This medication should be used only when clearly needed during pregnancy. Discuss the risks and benefits with your doctor. It is not known whether this drug is excreted into human milk. Consult your doctor before breast-feeding.

Drug Interactions

Tell your doctor of all nonprescription or prescription medication you may take. Do not start or stop any medicine without doctor or pharmacist approval.


If overdose is suspected, contact your local poison control center or emergency room immediately. Symptoms of overdose may include nausea, vomiting, diarrhea, unusual drowsiness or dizziness, headache, coughing, and difficulty breathing. This medicine may be harmful if swallowed or inhaled. If you or someone you know may have ingested or inhaled this medicine, contact your local poison control center or emergency room immediately.


Do not share this medication with anyone else unless directed otherwise by your doctor.

Missed Dose

If you miss a dose, consult your doctor or pharmacist.


Store at room temperature between 59 and 86 degrees F (15-30 degrees C) away from light and moisture. Keep container tightly closed. Do not freeze.