This is achieved because opioid antagonists have a greater affinity for the opiate receptor than agonists and in fact the affinity is so strong that narcotic antagonists can literally knock an agonist right out of the receptor. The effect is very fast and the overdose victim will wake up within minutes, or seconds even. Individuals dependent on heroin, or other opioids such as methadone can wake up in withdrawal. Heroin, methadone and morphine are opioid agonists. Narcotic antagonists are produced by a change on the nitrogen atom of an opioid agonist.
Naltrexone is a long acting narcotic antagonist which is used for maintenance treatment.
It works by binding to the receptor over a 24 hour period thus making any injection or administration of an opioid agonist ineffective. It must be emphasized that naltrexone does not have agonist properties it merely blocks every opiate receptor irrespective of that receptors function. Thus, long term treatment with narcotic antagonists can also block important biological functions and various side effects have been reported, including hypersexuality. Methadone and Congeners Germany has been a leader in the discovery and production of pharmaceuticals since the mid-Nineteenth Century. In the 1850s German scientists discovered the first molecular structure of a substance, which was morphine.