Its half-life is substantially greater than that of heroin, and while it is bound to receptors it blocks newly administered heroin. Its analgesic activity is also approximately equal to morphine's, but it imparts less euphoria. Stadol has been used nasally to relieve migraines. Although mixed agonists retain analgesic properties, they often impart dysphoric effects. Narcotic antagonists are especially useful in cases of overdose, where they can reverse the CNS depression caused by opiate agonists.
Naloxone is the most often used, most effective, and prototypal narcotic antagonist.
Naloxone, nalmefene, and nadide are among several other compounds used to antagonize morphine receptors. The product had a similar appearance and melting point, and they injected it expecting a demerol high. In the brain, MPTP decomposes to MPP which selectively binds to and destroys dopamine receptors. These individuals thus prematurely gave themselves Parkinson's disease. MPP closely resembles paraquat, a defoliant used by the US government, outside US borders, against marijuana.