Methylnaltrexone

Methylnaltrexone
Clinical data
Trade namesRelistor
Other namesMNTX, naltrexone-methyl-bromide
AHFS/Drugs.comMonograph
MedlinePlusa608052
License data
Pregnancy
category
Routes of
administration		Oral, intravenous, subcutaneous
ATC code
Legal status
Legal status
Pharmacokinetic data
Protein binding11–15.3%
MetabolismLiver
Elimination half-life8 hours
ExcretionUrine (50%), faeces (50%)
Identifiers
  • (5α)-17-(cyclopropylmethyl)-3,14-dihydroxy-17-methyl-4,5-epoxymorphinanium-17-ium-6-one
CAS Number
PubChem CID
IUPHAR/BPS
DrugBank
ChemSpider
UNII
ChEMBL
CompTox Dashboard (EPA)
ECHA InfoCard100.122.861 Edit this at Wikidata
Chemical and physical data
FormulaC21H26NO4
Molar mass356.442 g·mol−1
3D model (JSmol)
  • O=C6[C@@H]3Oc1c2c(ccc1O)C[C@@H]4[C@@](O)([C@@]23CC[N+]4(C)CC5CC5)CC6
  • InChI=1S/C21H25NO4/c1-22(11-12-2-3-12)9-8-20-17-13-4-5-14(23)18(17)26-19(20)15(24)6-7-21(20,25)16(22)10-13/h4-5,12,16,19,25H,2-3,6-11H2,1H3/p+1/t16-,19+,20+,21-,22?/m1/s1 checkY
  • Key:JVLBPIPGETUEET-GAAHOAFPSA-O checkY
 ☒NcheckY (what is this?)  (verify)

Methylnaltrexone (MNTX, brand name Relistor), used in form of methylnaltrexone bromide (INN, USAN, BAN), is a medication that acts as a peripherally acting μ-opioid receptor antagonist that acts to reverse some of the side effects of opioid drugs such as constipation without significantly affecting pain relief or precipitating withdrawals. Because MNTX is a quaternary ammonium cation, it cannot cross the blood–brain barrier, and so has antagonist effects throughout the body, counteracting effects such as itching and constipation, but without affecting opioid effects in the brain such as pain relief.[6] However, since a significant fraction (up to 60%) of opioid analgesia can be mediated by opioid receptors on peripheral sensory neurons, particularly in inflammatory conditions such as arthritis, traumatic or surgical pain,[7] MNTX may increase pain under such circumstances.

  1. ^ "Methylnaltrexone (Relistor) Use During Pregnancy". Drugs.com. 9 July 2020. Retrieved 21 September 2020.
  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 2023-08-16.
  3. ^ "Relistor Product information". Health Canada. 25 April 2012. Retrieved 6 September 2022.
  4. ^ "Relistor Product information". Health Canada. 25 April 2012. Retrieved 6 September 2022.
  5. ^ "Relistor Product information". Health Canada. 25 April 2012. Retrieved 6 September 2022.
  6. ^ National Prescribing Service (1 March 2010). "Methylnaltrexone injections (Relistor) for opioid-induced constipation in palliative care". Archived from the original on 2010-06-01. Retrieved 12 March 2010.
  7. ^ Stein C (January 1993). "Peripheral mechanisms of opioid analgesia". Anesthesia and Analgesia. 76 (1): 182–91. doi:10.1213/00000539-199301000-00031. PMID 8380316. S2CID 10113604.