1. synthetic insecticides derived from chrysanthemum flowers, commonly used to treat lice and scabies or as household pest control
Usage: medical; plural form

Examples

• The doctor prescribed a shampoo containing permethrins to treat the head lice.
• Permethrins are effective against mosquitoes and other flying insects.
• The veterinarian recommended permethrins for controlling fleas on pets.
• Many household insect sprays contain permethrins as active ingredients.
• Permethrins work by affecting the nervous system of insects.
• The cream with permethrins cleared up the scabies infection quickly.