Potassium cyanide is a very poisonous inorganic cyanide salt, which people can use instead of the more popular sodium cyanide. Its chemical formula is KCN. People mostly ship potassium cyanide in tablets, or powder form. If you are shipping from us, the available dosages are a 10mg oral tablet or potassium cyanide powder. Antiemetic drugs are associated to prevent vomiting.