What substances are commonly associated with histotoxic hypoxia?

Histotoxic hypoxia occurs when the tissues are unable to effectively use oxygen due to the presence of toxic substances. Cyanide is a well-known agent that inhibits cellular respiration by blocking the cytochrome c oxidase enzyme in the mitochondrial electron transport chain. This leads to a significant reduction in the cells' ability to utilize oxygen, despite normal levels of oxygen being present in the bloodstream. Alcohol can also have a similar effect by impairing cellular metabolic processes and affecting enzyme function, leading to reduced cellular respiration.

Thus, the association of cyanide and alcohol with histotoxic hypoxia is accurate because both substances interfere with the body's ability to utilize oxygen at the cellular level, resulting in hypoxia even when adequate oxygen is available in the environment or circulating blood.