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Trade namesMovantik, Moventig
Other namesPEGylated naloxol;[1] NKTR-118
  • (5α,6α)-4,5-epoxy-6-(3,6,9,12,15,18,21-heptaoxadocos-1-yloxy)-17-(2-propen-1-yl)morphinan-3,14-diol
Clinical data
  • US: C (Risk not ruled out)
Routes of
By mouth
External links
US NLMNaloxegol
License data
Legal status
Protein binding~4.2%
MetabolismLiver (CYP3A)
Elimination half-life6–11 h
ExcretionFeces (68%), urine (16%)
Chemical and physical data
Molar mass651.794 g·mol−1
3D model (JSmol)
  • InChI=1S/C34H53NO11/c1-3-9-35-10-8-33-30-26-4-5-27(36)31(30)46-32(33)28(6-7-34(33,37)29(35)25-26)45-24-23-44-22-21-43-20-19-42-18-17-41-16-15-40-14-13-39-12-11-38-2/h3-5,28-29,32,36-37H,1,6-25H2,2H3/t28-,29+,32-,33-,34+/m0/s1

Naloxegol, sold under the brand names Movantik and Moventig, is a medication used for opioid-induced constipation in people with long term non-cancer pain.[2] It may be used when laxatives are not effective.[3] It is taken by mouth.[2] It generally dose not affect pain management.[3]

Common side effects include abdominal pain, diarrhea, nausea, and headache.[2] Other side effects may include opioid withdrawal and gastrointestinal perforation.[2] Use in pregnancy has not shown harm; however such use has not been well studied.[4] Chemically it is naloxone attached to polyethylene glycol (PEF).[2] It is a peripherally acting μ-opioid receptor antagonist, which prevents opioids from binding to receptors in the gut.[2]

Naloxegol was approved for medical use in the United States and Europe in 2014.[2][5] In the United States it costs about 360 USD per month as of 2021.[6] This amount in the United Kingdom costs the NHS about £55.[3] As of 2015 it is no longer a controlled substance in the United States.[7]

Medical use

Naloxegol is indicated for the treatment of opioid-induced constipation (OIC) in patients with chronic non-cancer pain. It is recommended that any maintenance laxative be discontinued before starting naloxegol or be held for at-least 3 days. Naloxegol should be taken on an empty stomach at least two hours after the last meal.[8]

When given concomitantly with opioid analgesics, naloxegol reduced constipation-related side effects, while maintaining comparable levels of analgesia.[9]


It is generally taken at a dose of 25 mg per day.[2] This was found safe and well tolerated for 52 weeks.[10]

Mechanism of action

Chemically, naloxegol is a pegylated (polyethylene glycol-modified) derivative of α-naloxol. Specifically, the 6-α-hydroxyl group of α-naloxol is connected via an ether linkage to the free hydroxyl group of a monomethoxy-terminated n=7 oligomer of PEG, shown extending at the lower left of the molecule image at right. The "n=7" defines the number of two-carbon ethylenes, and so the chain length, of the attached PEG chain, and the "monomethoxy" indicates that the terminal hydroxyl group of the PEG is "capped" with a methyl group.[11] The pegylation of the 6-α-hydroxyl side chain of naloxol prevents the drug from crossing the blood-brain barrier (BBB).[9] As such, it can be considered the antithesis of the peripherally-acting opiate loperamide which is utilized as an opiate-targeting anti-diarrheal agent that does not cause traditional opiate side-effects due to its inability to accumulate in the central nervous system in normal subjects.


Naloxegol inhibits opioid binding in μ-opioid receptors in the gastrointestinal tract, thus decreasing the constipating effects (slowing of gastrointestinal motility and transit, hypertonicity, increased fluid reabsorption) associated with opioids.[12]

If naloxegol is coadministered with other opioid antagonists, there is a potential for additive effect and increased risk of opioid withdrawal.[8]


  1. Seifert R, Wieland T, Mannhold R, Kubinyi H, Folkers G (17 July 2006). G Protein-Coupled Receptors as Drug Targets: Analysis of Activation and Constitutive Activity. John Wiley & Sons. p. 227. ISBN 978-3-527-60695-5. Retrieved 14 May 2012.
  2. 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 "Naloxegol Monograph for Professionals". Retrieved 11 November 2021.
  3. 3.0 3.1 3.2 BNF 81: March-September 2021. BMJ Group and the Pharmaceutical Press. 2021. p. 71. ISBN 978-0857114105.
  4. "Naloxegol (Movantik) Use During Pregnancy". Retrieved 11 November 2021.
  5. "Moventig". Retrieved 11 November 2021.
  6. "Naloxegol Prices, Coupons & Savings Tips - GoodRx". GoodRx. Retrieved 11 November 2021.
  7. "Schedules of Controlled Substances: Removal of Naloxegol From Control". Archived from the original on 2016-03-09. Retrieved 2016-02-27.
  8. 8.0 8.1 "Movantik prescribing information highlights". AstraZeneca. Retrieved 2019-08-14.
  9. 9.0 9.1 Garnock-Jones KP (March 2015). "Naloxegol: a review of its use in patients with opioid-induced constipation". Drugs. 75 (4): 419–25. doi:10.1007/s40265-015-0357-2. PMID 25666542. S2CID 207488539.
  10. Webster L, Chey WD, Tack J, Lappalainen J, Diva U, Sostek M (October 2014). "Randomised clinical trial: the long-term safety and tolerability of naloxegol in patients with pain and opioid-induced constipation" (PDF). Alimentary Pharmacology & Therapeutics. 40 (7): 771–9. doi:10.1111/apt.12899. PMID 25112584. S2CID 34286557.
  11. Technically, the molecule that is attached via the ether link is O-methyl-heptaethylene glycol [that is, methoxyheptaethylene glycol, CH3OCH2CH2O(CH2CH2O)5CH2CH2OH], molecular weight 340.4, CAS number 4437-01-8. See Pubchem Staff (2016). "Compound Summary for CID 526555, Pubchem Compound 4437-01". PubChem Compound Database. Bethesda, MD, USA: NCBI, U.S. NLM. Archived from the original on 2016-02-05. Retrieved 28 January 2016.
  12. Garnock-Jones KP (March 2015). "Naloxegol: a review of its use in patients with opioid-induced constipation". Drugs. 75 (4): 419–25. doi:10.1007/s40265-015-0357-2. PMID 25666542. S2CID 207488539.

External links