<prompt> Not a pyrethram derivative?CypermethrinPermithrinDDTResmethrin  <response>: parks textbook of preventive and social medicine 23rd edition synthetic pyrethroids devoloped so far are tetramethrin,resethrin,prothrin and propahin they are now being devoloped to replace natural pyrethrins some are found to be as much as 10ttimes as effective as naturally occuring pyrethrins . 