is a drug used to counter the effects of overdosing with opioids
such as heroin and morphine. Specifically, naloxone is used
in opioid overdoses for countering life-threatening depression
of the central nervous system and respiratory system. The
drug is derived from baine and has an extremely high affinity
for µ-opioid receptors in the central nervous system.
Naloxone is a µ-opioid receptor
competitive antagonist and the rapid blockade of these receptors
often produce rapid onset of withdrawal symptoms. Naloxone
is injected usually through intravenous route for fastest
action. The drug acts after about two minutes and its effects
may last approximately 45 minutes. Naloxone has been shown
to reduce rates of fatal overdose with heroin.