Pharmacy Corner
Head Lice: A Lousy Situation! Why isn’t the medication working?
  • Resistance - Lice can develop resistance to many of the lice treatments. They are less likely to become resistant to NYDA® and Resultz®11
  • Misdiagnosis and over-diagnosis - Your child may not have lice and it could be something else
  • Lack of adherence - poor compliance for proper application of lice product, lack of secondary application or reapplication too soon after the first application
  • Using conditioner before treatment - conditioners coat the hair and make the medication not work as well
  • New infestation - Having lice doesn't protect you from another infestation. If you come into contact with lice again, you can get lice again
What is the difference between the over-the-counter products?

R&C®, Kwellada-P® and Nix® are insecticides that kill lice by paralyzing them. Resultz® kills lice by causing dehydration, and NYDA® kill lice by suffocating them.

Why is resistance less likely to develop for NYDA® and Resultz® than it is for the other products?

Lice are able to change their DNA to become resistant to insecticide chemicals, such as R&C®, Kwellada-P® and Nix®. They have a harder time doing so for Resultz® and NYDA® because these products have a physical mechanism of action.

Should I treat the entire family if my child has lice?

No, you should not treat the entire family unless the entire family has live lice in their scalp. Treating someone who does not have lice can promote resistance as well as cause unnecessary side effects.

I read online that mayonnaise, petrolatum jelly, olive oil, margarine, vinegar, thick hair gel and hot air can be used. Do they work?

No, these common household products do a very poor job in killing head lice and don't work as well as products you can purchase in your local drug store11,12.

Will shaving my head (or my child's head) work?

Yes, but who wants a completely shaved head?