Naloxone

Naloxone
Clinical data
Trade names	Narcan, others
Other names	EN-1530; N-Allylnoroxymorphone; 17-Allyl-4,5α-epoxy-3,14-dihydroxymorphinan-6-one, naloxone hydrochloride (USAN US)
AHFS/Drugs.com	Monograph
MedlinePlus	a612022
License data	US DailyMed: Naloxone;
Pregnancy; category	AU: B1;
Routes of; administration	Intranasal, intravenous, intramuscular
Drug class	Opioid antagonist
ATC code	A06AH04 (WHO) ; V03AB15 (WHO);
Legal status
Legal status	AU: S4 (Prescription only) / S3 (Pharmacist Only Medicine); BR: Class C1 (Other controlled substances); CA: OTC; DE: § 48 AMG/§ 1 MPAV (Prescription only); UK: POM (Prescription only); US: OTC / Rx-only; In general: ℞ (Prescription only);
Pharmacokinetic data
Bioavailability	2% (by mouth, 90% absorption but high first-pass metabolism); 43–54% (intranasal); 98% (intramuscular, subcutaneous)
Metabolism	Liver
Onset of action	IVTooltip intravenous injection: 2 min, ; IMTooltip intramuscular injection: 5 min
Elimination half-life	1–1.5 h
Duration of action	INTooltip Intranasal: 30–90 min ; IVTooltip Intravenous: 45 min ; IMTooltip Intramuscular: 30–120 min
Excretion	Urine, bile
Identifiers
	IUPAC name (4R,4aS,7aR,12bS)-4a,9-dihydroxy-3-(prop-2-en-1-yl)-2,3,4,4a,5,6-hexahydro-1H-4,12-methano[1]benzofurano[3,2-e]isoquinolin-7(7aH)-one;
CAS Number	465-65-6 ;
PubChem CID	5284596;
IUPHAR/BPS	1638;
DrugBank	DB01183 ;
ChemSpider	4447644 ;
UNII	36B82AMQ7N;
KEGG	D08249 ; as HCl: D01340 ;
ChEBI	CHEBI:7459 ;
ChEMBL	ChEMBL80 ;
CompTox Dashboard (EPA)	DTXSID8023349 ;
ECHA InfoCard	100.006.697
Chemical and physical data
Formula	C19H21NO4
Molar mass	327.380 g·mol−1
3D model (JSmol)	Interactive image;
	SMILES O=C1[C@@H]2OC3=C(O)C=CC4=C3[C@@]2([C@]5(CC1)O)CCN(CC=C)[C@@H]5C4;
	InChI InChI=1S/C19H21NO4/c1-2-8-20-9-7-18-15-11-3-4-12(21)16(15)24-17(18)13(22)5-6-19(18,23)14(20)10-11/h2-4,14,17,21,23H,1,5-10H2/t14-,17+,18+,19-/m1/s1 ; Key:UZHSEJADLWPNLE-GRGSLBFTSA-N ;
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Naloxone, sold under the brand name Narcan among others, is an opioid antagonist, a medication used to reverse or reduce the effects of opioids. For example, it is used to restore breathing after an opioid overdose. Effects begin within two minutes when given intravenously, five minutes when injected into a muscle, and ten minutes as a nasal spray. Naloxone blocks the effects of opioids for 30 to 90 minutes.

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 or taking medications that negatively affect the heart, 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 non-selective and competitive opioid receptor antagonist. It reverses the depression of the central nervous system and respiratory system caused by opioids.

Naloxone was patented in 1961 and approved for opioid overdose in the United States in 1971. It is on the World Health Organization's List of Essential Medicines.