Nalbuphine

Source: Wikipedia, the free encyclopedia.

Not to be confused with Nalorphine.
Nalbuphine
Skeletal formula
Ball-and-stick model of nalbuphine
Clinical data
Trade namesNubain, Nalpain, Nalbuphin, others
Other namesEN-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.comMonograph
MedlinePlusa682668
Pregnancy
category
  • B
subcutaneous
ATC code
Legal status
Legal status
  • AU: S4 (Prescription only)
  • BR: Class A2 (Narcotic drugs)[2]
  • CA: Schedule IV
  • US: Rx only (unscheduled)[1] Schedule IV in some states
  • Federally Uncontrolled (RX-only), except in KY, C-IV[3]
SCTooltip Subcutaneous injection: <15 minutes[8]
Elimination half-life~5 hours (3–6 hours)<[6]
Duration of action3–6 hours[8]
ExcretionUrine, bile, feces;[4] 93% within 6 hours[9]
Identifiers
  • (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
JSmol)
SMILES
  • O[C@@H]4[C@@H]5Oc1c2c(ccc1O)C[C@H]3N(CC[C@]25[C@@]3(O)CC4)CC6CCC6
  • 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 checkY
  • Key:NETZHAKZCGBWSS-CEDHKZHLSA-N checkY
  (verify)

Nalbuphine, sold under the brand names Nubain among others, is an opioid analgesic which is used in the treatment of pain.[6][10][8] It is given by injection into a vein, muscle, or fat.[6][8]

affinity for the δ-opioid receptor (DOR) and sigma receptors.[11][10]

Nalbuphine was patented in 1963[12] and was introduced for medical use in the United States in 1979.[13][14] It is marketed in many countries throughout the world.[15]

Medical uses

Nalbuphine is indicated for the relief of moderate to severe pain. It can also be used as a supplement to balanced anesthesia, for preoperative and postoperative analgesia, and for obstetrical analgesia during labor and delivery. However, a 2014 Cochrane Systematic Review concluded that from the included studies, there was limited evidence to demonstrate that "0.1 to 0.3 mg/kg nalbuphine compared to placebo might be an effective postoperative analgesic" for pain treatment in children.[16] Further research is therefore needed to compare nalbuphine with other postoperative opioids.[16]

Although nalbuphine possesses opioid antagonist activity, there is evidence that in nondependent patients it will not antagonize an opioid analgesic administered just before, concurrently, or just after an injection. Therefore, patients receiving an opioid analgesic, general anesthetics, phenothiazines, or other tranquilizers, sedatives, hypnotics, or other CNS depressants (including alcohol) concomitantly with Nalbuphine may exhibit an additive effect. When such combined therapy is contemplated, the dose of one or both agents should be reduced.[17]

In addition to relieving pain, nalbuphine has been shown to reduce morphine-induced

pruritus (itching).[18] Pruritus is a common side effect of morphine and other pure μ-opioid receptor (MOR) agonists. A systematic review of clinical trials concluded that nalbuphine is effective in counteracting morphine-induced pruritus, likely through central nervous system mechanisms.[19]

Evidence suggests that κ-opioid receptor (KOR) activation can counteract MOR-mediated effects in the brain.[20] This interaction may have broader implications for central nervous system disorders, including potential applications in treating Parkinson's disease, where KOR agonism and MOR antagonism have been shown to reduce levodopa-induced dyskinesia and normalize striatal function.[21] However, the mechanism by which nalbuphine relieves pruritus does not appear to involve this KOR–MOR interaction specifically.

Morphine-induced pruritus may also result from histamine release by mast cells in the skin.[22] Both MORs and KORs are expressed in skin nerves and keratinocytes, indicating potential peripheral mechanisms for opioid-induced pruritus.[23] Histamine-mediated responses such as increased capillary permeability and vasodilation have been observed following intradermal administration of some opioids. However, nalbuphine does not elicit either a wheal or flare response, suggesting it does not promote histamine release from mast cells.[24]

Available forms

Nalbuphine is available in two concentrations, 10 mg and 20 mg of nalbuphine hydrochloride per mL. Both strengths contain 0.94% sodium citrate hydrous, 1.26% citric acid anhydrous, 0.1% sodium metabisulfite, and 0.2% of a 9:1 mixture of methylparaben and propylparaben as preservatives; pH is adjusted, if necessary, with hydrochloric acid. The 10 mg/mL strength contains 0.1% sodium chloride. The drug is also available in a sulfite and paraben-free formulation in two concentrations, 10 mg and 20 mg of nalbuphine hydrochloride per mL. One mL of each strength contains 0.94% sodium citrate hydrous, 1.26% citric acid anhydrous; pH is adjusted, if necessary, with hydrochloric acid. The 10 mg/mL strength contains 0.2% sodium chloride.

An investigational extended-release oral formulation is under development by Trevi Therapeutics.[25]

Side effects

Like pure MOR agonists, the mixed agonist/antagonist opioid class of drugs can cause side effects with initial administration of the drug which lessens over time ("tolerance"). This is particularly true for the side effects of nausea, sedation and cognitive symptoms (Jovey et al. 2003). These side effects can in many instances be ameliorated or avoided at the time of drug initiation by titrating the drug from a tolerable starting dose up to the desired therapeutic dose. An important difference between nalbuphine and the pure MOR agonist opioid analgesic drugs is the "ceiling effect" on respiration (but no ceiling on the analgesic effect). Respiratory depression is a potentially fatal side effect from the use of pure MOR agonists. Nalbuphine has limited ability to depress respiratory function (Gal et al. 1982).[17]

As reported in the current Nubain Package Insert (2005), the most frequent side effect in 1066 patients treated with nalbuphine was sedation in 381 (36%).[17]

Other, less frequent reactions are: feeling sweaty/clammy 99 (9%), nausea/vomiting 68 (6%), dizziness/vertigo 58 (5%), dry mouth 44 (4%), and headache 27 (3%). Other adverse reactions which may occur (reported incidence of 1% or less) are:[17]

  • CNS effects: Nervousness, depression, restlessness, crying, euphoria, flushing, hostility, unusual dreams, confusion, faintness, hallucinations, dysphoria, feeling of heaviness, numbness, tingling, unreality. The incidence of psychotomimetic effects, such as unreality, depersonalization, delusions, dysphoria and hallucinations has been shown to be less than that which occurs with pentazocine.[26]
  • Cardiovascular: Hypertension, hypotension, bradycardia, tachycardia, pulmonary edema.
  • Gastrointestinal: Cramps, dyspepsia, bitter taste.
  • Respiration: Depression, dyspnea, asthma.
  • Dermatological: Itching, burning, urticaria.
  • Obstetric: Pseudo-sinusoidal fetal heart rhythm.

Other possible, but rare side effects include speech difficulty, urinary urgency, blurred vision, flushing and warmth.

A 2014 Cochrane Systematic Review by Schnabel et al., concluded that due to limited data, analysis of adverse events for children treated with nalbuphine compared to other opioids or placebo for postoperative pain, could not be definitively reported.[16]

Overdose

In case of overdose or adverse reaction, the immediate intravenous administration of naloxone (Narcan) is a specific antidote. Oxygen, intravenous fluids, vasopressors and other supportive measures should be used as indicated.[27] When administered concurrently with naloxone, nalbuphine is also useful for treating overdoses of potent opioids such as fentanyl, and its highly potent derivatives such as remifentanil and sufentanil, when naloxone alone is insufficient.[28]

Pharmacology

Pharmacodynamics

Nalbuphine at opioid receptors
Site
Ki
Tooltip Inhibitor constant
EC50
Tooltip Half-maximal effective concentration		 IATooltip Intrinsic activity Ref
MOR
Tooltip μ-Opioid receptor		 0.89 nM 14 nM 47% [11]
DOR
Tooltip δ-Opioid receptor		 240 nM ND ND [11]
KOR
Tooltip κ-Opioid receptor		 2.2 nM 27 nM 81% [11]

Nalbuphine is a

agonist/antagonist) of the MOR and as a high-efficacy partial agonist of the KOR.[11] Nalbuphine has weak or no affinity for the sigma receptor(s) (e.g., Ki > 100,000 nM).[10][29][30]

Nalbuphine is said to be more

confusion (<1%), hallucinations (<1%), depersonalization (1%), unusual dreams (<1%), and feelings of "unreality" (<1%).[32]

Nalbuphine is a potent analgesic. Its analgesic potency is essentially equivalent to that of morphine on a milligram basis, which is based on relative potency studies using intramuscular administration (Beaver et al. 1978). Oral administered nalbuphine is reported to be three times more potent than codeine (Okun et al. 1982). Clinical trials studied single dose experimental oral immediate release nalbuphine tablets for analgesic efficacy over a four- to six-hour time period following administration. Nalbuphine in the 15 to 60 mg range had similar analgesic effects to immediate release codeine in the 30 to 60 mg range (Kantor et al. 1984; Sunshine et al. 1983). Schmidt et al. (1985) reviewed the preclinical pharmacology of nalbuphine and reported comparative data relative to other types of opioid compounds. The authors point out that the nalbuphine moiety is approximately ten times more pharmacologically potent than the mixed opioid agonist/antagonist butorphanol on an "antagonist index" scale which quantitates the drug's ability to act both as an analgesic (via opioid KOR agonism) as well as a MOR antagonist. The opioid antagonist activity of nalbuphine is one-fourth as potent as nalorphine and 10 times that of pentazocine.

Pharmacokinetics

The

duration
of analgesic activity has been reported to range from 3 to 6 hours.

Chemistry

Nalbuphine is a

derivative of morphine
and is also known as N-cyclobutylmethyl-14-hydroxydihydronormorphine.

History

Nalbuphine was first synthesized in 1965 and was introduced for medical use in the United States in 1979.[14]

In the search for opioid analgesics with less abuse potential than pure MOR agonist opioids, a number of

agonist–antagonists
analgesics. Nalbuphine belongs to this group of substances. The mixed agonists-antagonists drug class exerts their analgesic actions by agonistic activity at the KOR. While all drugs in this class possess MOR antagonistic activity leading to less abuse potential, nalbuphine is the only approved drug in the mixed agonist–antagonist class listed in terms of its pharmacological actions and selectivities on opioid receptors as a MOR partial agonist or antagonist as well as a KOR agonist (Gustein et al. 2001).

Nubain was approved for marketing in the United States in 1978 and remains as the only opioid analgesic of this type (marketed in the U.S.) not controlled under the

Department of Health and Human Services
, nalbuphine was removed from schedule II of the CSA in 1976. Presently, nalbuphine is not a controlled substance under the CSA.

Nalbuphine HCL is currently available only as an injectable in the US and the European Union. Nubain, the Astra USA brand name for injectable nalbuphine HCL, was discontinued from being marketed in 2008 in the United States for commercial reasons (Federal Register 2008); however, other commercial suppliers now provide generic injection formulation nalbuphine for the market.

Society and culture

Brand names

Nalbuphine is marketed primarily under the brand names Nubain, Nalpain, and Nalbuphin.[15] It is also marketed under the brand name Nalufin in Egypt and Raltrox in Bangladesh by Opsonin Pharma Limited, under the brand name Rubuphine in India by Rusan Healthcare Pvt Ltd, under the brand name Kinz and Nalbin in Pakistan by Sami and Global Pharmaceuticals, under the brand name Analin by Medicaids in Pakistan, and under the brand name Exnal by Indus Pharma in Pakistan, among many others.[15]

Unlike many other opioids, nalbuphine has a limited potential for euphoria, and in accordance, is rarely abused.[6][32] This is because whereas MOR agonists produce euphoria, MOR antagonists do not, and KOR agonists like nalbuphine moreover actually produce dysphoria.[6][31] Nalbuphine was initially designated as a Schedule II controlled substance in the United States along with other opioids upon the introduction of the 1970 Controlled Substances Act.[6] However, its manufacturer, Endo Laboratories, Inc., petitioned the Food and Drug Administration to remove it from Schedule II in 1973, and after a medical and scientific review, nalbuphine was removed completely from the Controlled Substances Act in 1976 and is not a controlled substance in the United States today.[6][31] For comparison, MOR full agonists are all Schedule II in the United States, whereas the mixed KOR and MOR agonists/antagonists butorphanol and pentazocine are Schedule IV in the United States.[31] In Canada, most opioids are classified as Schedule I, but nalbuphine and butorphanol are both listed as Schedule IV substances.[33]

See also

Notes

  1. ^ "Nalbuphine Hydrochloride" (PDF). DEA - Diversion Control Division. Drug Enforcement Administration. Retrieved 31 March 2025.
  2. ^ Anvisa (2023-03-31). "RDC Nº 784 - Listas de Substâncias Entorpecentes, Psicotrópicas, Precursoras e Outras sob Controle Especial" [Collegiate Board Resolution No. 784 - Lists of Narcotic, Psychotropic, Precursor, and Other Substances under Special Control] (in Brazilian Portuguese). Diário Oficial da União (published 2023-04-04). Archived from the original on 2023-08-03. Retrieved 2023-08-03.
  3. ^ "Kentucky Penal Code: Title 902 Chapter 55 Regulation 015 - Controlled Substances". Kentucky Law. © 2024 Kentucky Legislative Research Commission.
  4. ^
    ISBN 978-1-60795-213-8
    .
  5. ^ Excerpta medica. Section 24: Anesthesiology. 1988. The mean absolute bioavailability was 81% and 83% for the 10 and 20 mg intramuscular doses, respectively, and 79% and 76% following 10 and 20 mg of subcutaneous nalbuphine.
  6. ^
    S2CID 25378355
    .
  7. ^
    ISBN 978-1-4377-3603-8
    .
  8. ^
    ISBN 978-0-521-75910-6
    .
  9. PMID 7769781
    .
  10. ^
    PMID 2986929
    .
  11. ^
    PMID 17407276
    .
  12. ^ US Patent 3393197 - Nusubstituted-14-hydroxydihydronormorphines
  13. ISBN 9783527607495
    .
  14. ^
    ISBN 978-0-323-07596-1
    .
  15. ^ a b c "Nalbuphine".
  16. ^
    PMID 25079857
    .
  17. ^ a b c d "NUBAIN® (Nalbuphine Hydrochloride) Drug Information Packet" (PDF). FDA.gov. © Par Pharmaceutical. 2016. pp. 02–04. Retrieved 31 March 2025.
  18. ^ Mathai F, Portugal F, Mehta Z, Davis M (July 2019). "Fast Facts and Concepts #381: Nalbuphine". Palliative Care Network of Wisconsin. Fast Facts & Concepts. Retrieved 31 March 2025.
  19. PMID 11412287
    .
  20. PMID 35497636
    .
  21. PMID 25820831
    .
  22. PMID 7694026
    .
  23. PMID 33536279
    .
  24. PMID 2470272
    .
  25. ^ "Haduvio™". Trevi Therapeutics. Retrieved 3 September 2024.
  26. ^ "nalbuphine hydrochloride injection Adverse Reactions | Pfizer Medical Information - US". www.pfizermedicalinformation.com. Retrieved 2023-03-03.
  27. ^ "Nalbuphine Hydrochloride Injection Overdosage". Pfizer Medical Information. ©2025 Pfizer Inc. Retrieved 31 March 2025.
  28. PMID 39065717
    .
  29. PMID 8093631
    .
  30. PMID 1964225
    .
  31. ^
    ISBN 978-3-319-60016-1
    .
  32. ^
    ISBN 978-0-88048-868-6
    .
  33. ISBN 978-1-77338-052-0
    .
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