Metaxalone

Metaxalone
Clinical data
Trade names	Skelaxin
AHFS/Drugs.com	Monograph
MedlinePlus	a682010
License data	US DailyMed: Metaxalone;
Routes of; administration	By mouth
ATC code	None;
Legal status
Legal status	US: ℞-only;
Pharmacokinetic data
Bioavailability	Unknown
Metabolism	Liver
Elimination half-life	9.2 ± 4.8 hours
Excretion	Kidney
Identifiers
	IUPAC name 5-[(3,5-dimethylphenoxy)methyl]-1,3-oxazolidin-2-one;
CAS Number	1665-48-1 ;
PubChem CID	15459;
IUPHAR/BPS	7609;
DrugBank	DB00660 ;
ChemSpider	14709 ;
UNII	1NMA9J598Y;
KEGG	D00773 ;
ChEMBL	ChEMBL1079604 ;
CompTox Dashboard (EPA)	DTXSID3023269 ;
ECHA InfoCard	100.015.253
Chemical and physical data
Formula	C12H15NO3
Molar mass	221.256 g·mol−1
3D model (JSmol)	Interactive image;
	SMILES O=C2OC(COc1cc(cc(c1)C)C)CN2;
	InChI InChI=1S/C12H15NO3/c1-8-3-9(2)5-10(4-8)15-7-11-6-13-12(14)16-11/h3-5,11H,6-7H2,1-2H3,(H,13,14) ; Key:IMWZZHHPURKASS-UHFFFAOYSA-N ;
	(verify)

Metaxalone, sold under the brand name Skelaxin, is a muscle relaxant medication used to relax muscles and relieve pain caused by strains, sprains, and other musculoskeletal conditions.^[1] Its exact mechanism of action is not known, but it may be due to general central nervous system depression.^[1] It is a moderately strong muscle relaxant, with relatively low incidence of side effects.^{[citation needed]}

Common side effects include nausea, vomiting, drowsiness, and central nervous system (CNS) side effects, such as dizziness, headache, and irritability.^[1]

The metabolism of metaxalone involves enzymes CYP1A2 and CYP2C19 in the cytochrome P450 system. ^{[medical citation needed]} Because many medications are metabolized by enzymes in this system, precaution must be taken when administering it with other medications involving the P450 system to avoid interactions.^[2]

Because of the potential for side effects, this drug is considered high risk in the elderly.^{[medical citation needed]}

Pharmacokinetics

Metaxalone exhibits increased bioavailability when taken with food.^[3] Specifically, in one study, compared to fasted conditions, the presence of food at the time of drug administration increased C_max by 77.5%, AUC_0-t by 23.5%, and AUC_0-∞ by 15.4%.^[4] Metaxalone is a substrate of CYP1A2 and CYP2C19, an inhibitor of CYP1A2, CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP2E1, and CYP3A, and an inducer of CYP1A2 and CYP3A4.^[2]

Assay

A literature survey reveals very few methods are reported for the determination of metaxalone to date. Nirogi et al.^[4] reported a liquid chromatographic method coupled to tandem mass spectrometry for the quantification of metaxalone in human plasma. A stability-indicating HPLC method was introduced by P.K. Sahu et al.^[5] Metaxalone has been used as an internal standard for few analytical methods.^[6]^[7]

References

^ ^a ^b ^c ^d "Skelaxin- metaxalone tablet". DailyMed. U.S. National Library of Medicine. 27 April 2018. Retrieved 23 October 2020.
^ ^a ^b US 7378434, Du J, Roberts RH, "Metaxalone products, method of manufacture, and method of use", issued 27 May 2008, assigned to Takeda Pharmaceuticals USA Inc.
^ "Skelaxin Package Insert". King Pharmaceuticals, Inc. Archived from the original on 9 March 2010.
^ ^a ^b Nirogi RV, Kandikere VN, Shukla M, Mudigonda K, Shrivastava W, Datla PV (May 2006). "Quantification of metaxalone in human plasma by liquid chromatography coupled to tandem mass spectrometry". Journal of Analytical Toxicology. 30 (4): 245–251. doi:10.1093/jat/30.4.245. PMID 16803662.
^ Sahu PK, Annapurna MM, Kumar SD (2011). "Development and Validation of Stability Indicating RP-HPLC Method for the Determination of Metaxalone in Bulk and its Pharmaceutical Formulations". e-Journal of Chemistry. 8 (s1): S439–S447. doi:10.1155/2011/645710.
^ Mistri HN, Jangid AG, Pudage A, Gomes N, Sanyal M, Shrivastav P (June 2007). "High throughput LC-MS/MS method for simultaneous quantification of lamivudine, stavudine and nevirapine in human plasma". Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences. 853 (1–2): 320–332. doi:10.1016/j.jchromb.2007.03.047. PMID 17481969.
^ Mistri HN, Jangid AG, Pudage A, Shrivastav P (March 2008). "HPLC-ESI-MS/MS validated method for simultaneous quantification of zopiclone and its metabolites, N-desmethyl zopiclone and zopiclone-N-oxide in human plasma". Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences. 864 (1–2): 137–148. doi:10.1016/j.jchromb.2008.02.004. PMID 18313371.

External links

"Metaxalone". Drug Information Portal. U.S. National Library of Medicine.

[Skelaxin_FDA_label-1] "Skelaxin- metaxalone tablet". DailyMed. U.S. National Library of Medicine. 27 April 2018. Retrieved 23 October 2020.

[label_change_patent-2] US 7378434, Du J, Roberts RH, "Metaxalone products, method of manufacture, and method of use", issued 27 May 2008, assigned to Takeda Pharmaceuticals USA Inc.

[3] "Skelaxin Package Insert". King Pharmaceuticals, Inc. Archived from the original on 9 March 2010.

[pmid16803662-4] Nirogi RV, Kandikere VN, Shukla M, Mudigonda K, Shrivastava W, Datla PV (May 2006). "Quantification of metaxalone in human plasma by liquid chromatography coupled to tandem mass spectrometry". Journal of Analytical Toxicology. 30 (4): 245–251. doi:10.1093/jat/30.4.245. PMID 16803662.

[5] Sahu PK, Annapurna MM, Kumar SD (2011). "Development and Validation of Stability Indicating RP-HPLC Method for the Determination of Metaxalone in Bulk and its Pharmaceutical Formulations". e-Journal of Chemistry. 8 (s1): S439–S447. doi:10.1155/2011/645710.

[6] Mistri HN, Jangid AG, Pudage A, Gomes N, Sanyal M, Shrivastav P (June 2007). "High throughput LC-MS/MS method for simultaneous quantification of lamivudine, stavudine and nevirapine in human plasma". Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences. 853 (1–2): 320–332. doi:10.1016/j.jchromb.2007.03.047. PMID 17481969.

[7] Mistri HN, Jangid AG, Pudage A, Shrivastav P (March 2008). "HPLC-ESI-MS/MS validated method for simultaneous quantification of zopiclone and its metabolites, N-desmethyl zopiclone and zopiclone-N-oxide in human plasma". Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences. 864 (1–2): 137–148. doi:10.1016/j.jchromb.2008.02.004. PMID 18313371.

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