Cyanide is a rapidly-acting, potentially lethal poison. Exposure typically occurs via administration of nitroprusside (a cyanide-containing vasodilating drug) or by inhalation of smoke in fires.
Cyanide exerts its effects by inhibiting Complex IV of the electron transport chain, thereby preventing aerobic respiration. The clinical picture is caused by reduced ability to utilize oxygen, and includes tissue hypoxia unresponsive to supplemental oxygen, cherry red skin discoloration, bright red venous blood, and almond breath odor.
Treatment involves first administering nitrites and following with thiosulfate, although hydroxycobalamin can also be used.
Find Cyanide Poisoning and more Toxins among Pixorize's visual mnemonics for the USMLE Step 1 and NBME Shelf Exams.