Cytochrome oxidase is inhibited by

Site I: This involves the transfer of electrons from NADH-CoQ. Obviously, this step is omitted by succinic dehydrogenase whose FADH2 prosthetic group transfers its electrons directly to CoQ bypassing NADH. This step is blocked by piericidin, rotenone, amobarbital, ceain drugs like chlorpromazine, guanethidine. among barbital is a barbiturate derivativeRef: MN Chatterjea Textbook of Medical Biochemistry, 8th Edition, Page no: 143