metaxalone

Action and Spectrum

Actions and Spectrum 

Actions: 

• Muscle Relaxation: metaxalone acts as a centrally acting muscle relaxant, affecting the central nervous system to induce muscle relaxation. It works by inhibiting nerve impulses or pain signals sent to the brain. 
• Pain Relief: By reducing muscle spasms and tension, metaxalone can help alleviate pain from musculoskeletal conditions like muscle strains, sprains, and other injuries. 
• Sedation: metaxalone can have sedative effects due to its action on the central nervous system. This can lead to drowsiness and a calming effect, which is sometimes desired in cases where muscle spasms are causing discomfort and affecting sleep. 

Spectrum: 

metaxalone is primarily indicated for short-term use (generally up to 3 weeks) in treating acute, painful musculoskeletal conditions. It is not intended for long-term use, as its effectiveness may diminish over time, and there is a potential for developing tolerance or dependency. 

Drug Interaction

Adverse Reaction

Frequency not defined 

Skin rash 

Pruritis 

Nausea 

Gastrointestinal distress 

Anaphylaxis 

Irritability 

Dizziness 

Nervousness 

Muscle cramps 

Hypersensitivity 

Black Box Warning

Black Box Warning: 

None 

Contraindication / Caution

Contraindication/Caution: 

Contraindications: 

• Hypersensitivity 
• Renal impairment 
• Liver impairment 
• Anemia 

Cautions: 

• Sedation 
• Alcohol 
• CNS depressants 
• Other medical conditions 
• Pregnancy 
• Breastfeeding 

Pregnancy / Lactation

Pregnancy consideration:  

Pregnancy Category: C 

Breastfeeding warnings:  

It is not known whether the drug is excreted in the breast milk.  

Pregnancy category: 

Category A: Well-controlled and satisfactory studies show no risk to the fetus in the initial or later trimester. 

Category B: There was no evidence of risk to the fetus in animal studies, and there were not enough studies on pregnant women. 

Category C: There was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women.    

Category D: adequate data with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits.    

Category X: Drugs listed in this category outweigh the risks over benefits. Hence, these categories of drugs need to be avoided by pregnant women.    

Category N: No data is available for the drug under this category. 

Pharmacology

Pharmacology:  

metaxalone is a muscle relaxant that primarily acts on the CNS to relieve muscle spasms and discomfort associated with acute, painful musculoskeletal conditions. It involves the modulation of neural pathways that control muscle contractions and pain perception. 

Pharmacodynamics: 

metaxalone has mild central nervous system depressant properties, leading to sedation and drowsiness. This effect is likely a result of its interaction with GABA receptors and other neurotransmitter systems in the brain. It’s important to note that this sedative effect can impact an individual’s ability to perform tasks requiring focus and attention, such as driving or operating heavy machinery. 

Pharmacokinetics: 

Absorption 

It takes 1 hour for the onset of action 

The duration of action is 4-6 hours 

The time taken to achieve peak plasma concentration is 296 mcg/ml 

Distribution 

The volume of distribution is 800L. 

Metabolism 

metaxalone undergoes extensive metabolism in the liver. 

Elimination and Excretion 

The elimination half-life of metaxalone is 4-14 hours 

The drug is excreted in the urine 

Adminstartion

Administration: 

metaxalone can be taken with or without food. Taking it with food might help reduce the likelihood of stomach upset. 

Ensure you drink plenty of water when taking metaxalone to stay well-hydrated. 

metaxalone is typically used for short-term treatment due to its potential for tolerance and limited efficacy beyond that time frame. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: metaxalone 

Pronounced as: meh-tah-zal-one 

Why do we use metaxalone? 

• Muscle Spasms: metaxalone is particularly effective in reducing muscle spasms, which cause pain, stiffness, and limited range of motion. These spasms can result from various conditions, including muscle strains, sprains, injuries, or underlying musculoskeletal issues. 
• Musculoskeletal Pain: metaxalone helps relieve musculoskeletal pain due to muscle spasms. Reducing muscle tension indirectly alleviates pain associated with these conditions. 
• Physical Therapy and Rest: metaxalone is often used in combination with rest and physical therapy to enhance the effectiveness of treatment. By reducing muscle spasms and tension, patients may find it easier to engage in physical therapy exercises and recover more effectively. 
• Short-Term Relief: metaxalone is typically recommended for short-term use, generally up to three weeks. It is not intended for long-term treatment due to its potential for tolerance development and limited efficacy beyond this time frame.