If you are addicted to opiate narcotic drugs, naltrexone or narcan will make you so sick. Sure it may save your life in an overdose but when you wake up in a ER after a narcan shot the last thing you feel in gratitude. Theses drugs are sometimes given to addicts when they are awake by a cruel or unaware paramedic nurse or doctor and it's extremly hurtfull. I hope nobody had to experience this. Another problem with these drugs is that if you are on them and get into an accident or need emergency pain relief, you could be SOL. All the best