Nalbuphine

Nalbuphine
Clinical data
Trade names	Nubain, Nalpain, Nalbuphin, others
Other names	EN-2234A; N-Cyclobutylmethyl-14-hydroxydihydronormorphine; 17-Cyclobutylmethyl-4,5α-epoxymorphinan-3,6α,14-triol; N-Cyclobutylmethyl-4,5α-epoxy-3,6α,14-morphinantriol
AHFS/Drugs.com	Monograph
MedlinePlus	a682668
Pregnancy; category	B;
Routes of; administration	Intravenous, intramuscular, subcutaneous
ATC code	N02AF02 (WHO) ;
Legal status
Legal status	AU: S4 (Prescription only); BR: Class A2 (Narcotic drugs); CA: Schedule IV; US: Rx only (unscheduled) Schedule IV in some states; Federally Uncontrolled (RX-only), except in KY, C-IV;
Pharmacokinetic data
Bioavailability	• Oral: 11% (young adults), >44% (elderly); • IMTooltip Intramuscular injection: 81% (10 mg), 83% (20 mg); • SCTooltip Subcutaneous injection: 76% (20 mg), 79% (10 mg)
Protein binding	50%
Metabolism	Liver (glucuronidation)
Metabolites	Glucuronide conjugates (inactive), others
Onset of action	• Oral: <1 hour; • Rectal: <30 minutes; • IVTooltip Intravenous injection: 2–3 minutes; • IMTooltip Intramuscular injection: <15 minutes; • SCTooltip Subcutaneous injection: <15 minutes
Elimination half-life	~5 hours (3–6 hours)<
Duration of action	3–6 hours
Excretion	Urine, bile, feces; 93% within 6 hours
Identifiers
	IUPAC name (4R,4aS,7S,7aR,12bS)-3-(cyclobutylmethyl)-1,2,4,5,6,7,7a,13-octahydro-4,12-methanobenzofuro[3,2-e]isoquinoline-4a,7,9-triol;
CAS Number	20594-83-6 ;
PubChem CID	5311304;
IUPHAR/BPS	1663;
DrugBank	DB00844 ;
ChemSpider	4470813 ;
UNII	L2T84IQI2K;
ChEBI	CHEBI:7454 ;
ChEMBL	ChEMBL895 ;
CompTox Dashboard (EPA)	DTXSID8023345 ;
ECHA InfoCard	100.039.895
Chemical and physical data
Formula	C21H27NO4
Molar mass	357.450 g·mol−1
3D model (JSmol)	Interactive image;
	SMILES O[C@@H]4[C@@H]5Oc1c2c(ccc1O)C[C@H]3N(CC[C@]25[C@@]3(O)CC4)CC6CCC6;
	InChI InChI=1S/C21H27NO4/c23-14-5-4-13-10-16-21(25)7-6-15(24)19-20(21,17(13)18(14)26-19)8-9-22(16)11-12-2-1-3-12/h4-5,12,15-16,19,23-25H,1-3,6-11H2/t15-,16+,19-,20-,21+/m0/s1 ; Key:NETZHAKZCGBWSS-CEDHKZHLSA-N ;
	(verify)

Nalbuphine, sold under the brand names Nubain among others, is an opioid analgesic which is used in the treatment of pain. It is given by injection into a vein, muscle, or fat.

Side effects of nalbuphine include sedation, sweatiness, clamminess, nausea, vomiting, dizziness, vertigo, dry mouth, and headache. Unlike other opioids, it has little to no capacity to cause euphoria or respiratory depression. There is also little to no incidence of dysphoria, dissociation, hallucinations, and related side effects at typical therapeutic doses. Nalbuphine is a mixed agonist/antagonist opioid modulator. Specifically, it acts as a moderate-efficacy partial agonist or antagonist of the μ-opioid receptor (MOR) and as a high-efficacy partial agonist of the κ-opioid receptor (KOR), whereas it has relatively low affinity for the δ-opioid receptor (DOR) and sigma receptors.

Nalbuphine was patented in 1963 and was introduced for medical use in the United States in 1979. It is marketed in many countries throughout the world.