Fraser proved that by substitution of molecules in certain compounds a stimulant could be converted into a sedative action; thus by the addition of the methyl group CH 2 to the molecule of strychnine, thebaine or brucine, the tetanizing action of these drugs is converted into a paralysing action.
Cotarnine IV.Narceine The chemistry of morphine, codeine and thebaine is exceedingly complicated, and the literature enormous.
Crum Brown and Fraser of Edinburgh showed that, whilst thebaine acts like strychnine, methyl and ethyl thebaine act like curara, paralysing the terminals of motor nerves.
The alkaloid thebaine may here be referred to, as it is not used separately in medicine.
In morphine, on the higher animals at least, the narcotic action is very marked, the tetanizing action slightly so; while in thebaine there is little narcotic effect, but a tetanizing action like that of strychnine.