FPGEE for National Association of Boards of Pharmacy (NABP) Practice Exam 2026 - Free NABP Practice Questions and Study Guide

Sodium nitrite plays a critical role in the treatment of cyanide poisoning by converting hemoglobin into methemoglobin. This is significant because methemoglobin has a higher affinity for cyanide compared to regular hemoglobin. When sodium nitrite is administered, it oxidizes the ferrous iron (Fe2+) in hemoglobin to ferric iron (Fe3+), forming methemoglobin. This newly formed methemoglobin can then bind to cyanide, effectively sequestering it and preventing it from interfering with cellular respiration.

The ability of methemoglobin to bind cyanide is leveraged in clinical treatment, as it helps to reduce the toxic effects cyanide has on the body's tissues, especially in the context of inhibiting cytochrome c oxidase within the mitochondrial electron transport chain. By converting hemoglobin to methemoglobin, sodium nitrite facilitates the detoxification of cyanide, enabling further treatment options, such as the administration of hydroxocobalamin, which can convert the bound cyanide into a less toxic compound that can be safely eliminated from the body.

Other options do not relate to the specific mechanism of action for treating cyanide poisoning, and the involvement of sodium nitrite in enhancing cardiac activity or affecting potassium levels is not part of