What is "naloxone"

n. A drug used to counter the effects of an overdose on opioids (such as heroin or morphine).

n. a potent narcotic antagonist (trade name Narcan) especially effective with morphine [syn: Narcan]

Naloxone, sold under the brandname Narcan among others, is a medication used to block the effects of opioids, especially in overdose. Naloxone may be combined within the same pill as an opioid to decrease the risk of misuse. When given intravenously, it works within two minutes, and when injected into a muscle, it works within five minutes. The medication may also be used in the nose. The effects of naloxone last about half an hour to an hour. Multiple doses may be required, as the duration of action of most opioids is greater than that of naloxone.

Administration to opioid-dependent individuals may cause symptoms of opioid withdrawal, including restlessness, agitation, nausea, vomiting, a fast heart rate and sweating. To prevent this, small doses every few minutes can be given until the desired effect is reached. In those with previous heart disease, further heart problems have occurred. It appears to be safe in pregnancy, after having been given to a limited number of women. Naloxone is a pure opioid antagonist. It works by reversing the depression of the central nervous system and respiratory system caused by opioids.

Naloxone was patented in 1961 by Jack Fishman, Mozes J. Lewenstein, and the company Sankyo. The drug was approved for opioid overdose by the Food and Drug Administration in 1971. Naloxone is on the World Health Organization's List of Essential Medicines, the most important medications needed in a basic health system. Naloxone is available as a generic medication and is not very expensive. Its wholesale price in the developing world is between 0.50 and 5.30 USD per dose.