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 a 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. 27 April 2018. Retrieved 23 October 2020.
^ ^a ^b United States Patent No. 7,378,434, by Jie Du, et al
^ Skelaxin Package Insert
^ ^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". J Anal Toxicol. 30 (4): 245–51. doi:10.1093/jat/30.4.245. PMID 16803662.
^ Sahu, Prafulla Kumar; Annapurna, M. Mathrusri; Kumar, Sahoo Dillip (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 (15 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): 320–32. doi:10.1016/j.jchromb.2007.03.047. PMID 17481969.
^ Mistri, HN; Jangid, AG; Pudage, A; Shrivastav, P (15 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): 137–48. 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. 27 April 2018. Retrieved 23 October 2020.

[label_change_patent-2] United States Patent No. 7,378,434, by Jie Du, et al

[3] Skelaxin Package Insert

[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". J Anal Toxicol. 30 (4): 245–51. doi:10.1093/jat/30.4.245. PMID 16803662.

[5] Sahu, Prafulla Kumar; Annapurna, M. Mathrusri; Kumar, Sahoo Dillip (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 (15 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): 320–32. doi:10.1016/j.jchromb.2007.03.047. PMID 17481969.

[7] Mistri, HN; Jangid, AG; Pudage, A; Shrivastav, P (15 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): 137–48. doi:10.1016/j.jchromb.2008.02.004. PMID 18313371.

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