From a recent article of our doc magazine (particular for docs although I managed to get a member) called "Auto-intoxication with "suicide powder".
I will only quote/translate the start and that what stood out the most to me;
Ladies and gentlemen,
We have recently been confronted with suicide attempts with sodium nitrite. Like sodium azide, this agent is considered to be the "suicide powder" or "agent X". In this clinical lesson we discuss the symptoms, pathophysiology, treatment and the mechanism of death after taking sodium nitrite based on 2 patients.
Media coverage has created the impression among the public that sodium nitrite is a "safe and humane agent" that "leads to a dignified death." 2 The mechanism of death, however, is suffocation, with after death permanent blue discoloration of the entire body. Because of the unbearable symptoms associated with suffocation, sodium nitrite is an extremely unsuitable suicide agent.
If anyone is interested I can send the entire article per email (I tried other ways to share but it is impossible) but you will then have to translate it yourself.