<unk>  is a cyanide antidote that is FDA approved for the treatment of acute cyanide poisoning. There is a Black Box Warning for this drug as shown here.  Common adverse reactions include syncope, hypotension, tachycardia, methemoglobinemia, palpitations, dysrhythmia, methemoglobinemia, headache, dizziness, blurred vision.
Sodium nitrite
Amyl nitrite
Calcium oxide
Ceric ammonium nitrate
Oxitropium bromide
Manganese dioxide
Magnesium peroxide
Arsenic pentoxide