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| Clinical data | |
|---|---|
| Trade names | Skelaxin |
| AHFS/Drugs.com | Monograph |
| MedlinePlus | a682010 |
| License data |
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| Routes of administration | By mouth |
| ATC code |
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| Legal status | |
| Legal status | |
| Pharmacokinetic data | |
| Bioavailability | Unknown |
| Metabolism | Liver |
| Elimination half-life | 9.2 ± 4.8 hours |
| Excretion | Kidney |
| Identifiers | |
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| CAS Number | |
| PubChem CID | |
| IUPHAR/BPS | |
| DrugBank | |
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| ChEMBL | |
| CompTox Dashboard (EPA) | |
| ECHA InfoCard | 100.015.253 |
| Chemical and physical data | |
| Formula | C12H15NO3 |
| Molar mass | 221.256 g·mol−1 |
| 3D model (JSmol) | |
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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 ]
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 Cmax by 77.5%, AUC0-t by 23.5%, and AUC0-∞ 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]
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]