The chemical Permethrin has a designated molecular formula of C21H20Cl2O3 and a molecular weight of 391.288 g/mol. Synonyms may include: S-3151, S 3151, AI3-29158, Ambush, Ambushfog, Anomethrin N, Antiborer 3768, BRN 2063148, BW-21-Z, Caswell No. 652BB, CCRIS 2001, Chinetrin (ChemID). Permethrin has been assigned a MeSH pharmacological action of: Enzyme Inhibitor.