• Skelaxin (metaxalone) and baclofen are skeletal muscle relaxants.
• A main difference is that Skelaxin is used mostly for short-term painful muscle and skeletal conditions, while baclofen may be used long-term for spasms of skeletal muscles, muscle rigidity, muscle clonus, and pain caused by disorders like multiple sclerosis.
• Brand names for baclofen include Gablofen and Lioresal.
• Side effects of Skelaxin and baclofen that are similar include dizziness, drowsiness, headache, nausea, and vomiting.
• Side effects of Skelaxin that are different from baclofen include nervousness, irritability, upset stomach, rash, anemia, low white blood cell count, yellowing skin and eyes (jaundice), and allergic reactions
• Side effects of baclofen that are different from Skelaxin include weakness, seizures, low blood pressure, constipation, confusion, respiratory depression, inability to sleep (insomnia), and increased urinary frequency or urinary retention.
• Suddenly stopping oral baclofen may cause withdrawal reactions such as seizures and hallucinations. Suddenly stopping intrathecal baclofen may result in high fever, rebound spasticity, muscle rigidity, and rhabdomyolysis (muscle breakdown) that can progress to failure of several organs, including the kidney, and even death.

Skelaxin (metaxalone) is an oral drug that relaxes skeletal muscle, the muscles that control movement of the body. Skelaxin is prescribed as an adjunct to physical therapy for the treatment of short-term painful muscle and skeletal conditions.

Baclofen is a medication that relaxes skeletal muscles. Baclofen is prescribed for the treatment of spasms of skeletal muscles, muscle rigidity, muscle clonus, and pain caused by disorders like multiple sclerosis. Chemically, baclofen is related to gamma-aminobutyric acid (GABA), a naturally occurring neurotransmitter in the brain. GABA released by some nerves causes the activity of other nerves to decrease. It is thought baclofen acts like GABA and blocks the activity of nerves within the part of the brain that controls the contraction and relaxation of skeletal muscle.

Skelaxin

The most common side effects with metaxalone are:

• drowsiness,
• dizziness,
• headache,
• nervousness,
• irritability,
• nausea,
• vomiting, and
• upset stomach.

Other important, but less common, side effects include:

• rash,
• anemia,
• low white blood cell count,
• jaundice, and
• allergic reactions

Baclofen

Common side effects of baclofen are:

• drowsiness,
• weakness,
• dizziness,
• headache,
• seizures,
• nausea,
• vomiting,
• low blood pressure,
• constipation,
• confusion,
• respiratory depression,
• inability to sleep, and
• increased urinary frequency or urinary retention.

Abrupt discontinuation of oral baclofen may cause seizures and hallucinations. Abrupt discontinuation of intrathecal baclofen may result in:

• high fever,
• rebound spasticity,
• muscle rigidity, and
• rhabdomyolysis (muscle breakdown) that can progress to failure of several organs, including the kidney, and even death.

Skelaxin

Metaxalone usually is taken at a dose of 800 mg, three or four times daily. Benefits are seen within one hour of ingestion. Food high in fat content increases the absorption of metaxalone.

Baclofen

The usual starting dose of oral baclofen for treating spasticity in adults is 5 mg given three times daily. Based on the response, the dose can be increased by 5 mg every three days to a maximum of 80 mg/day in divided doses.

Skelaxin

No important drug interactions have been described with metaxalone. Metaxalone may increase the sedative effects of alcohol and drugs that cause sedation, for example, benzodiazepines (Valium), antidepressants, opioids (morphine).

Baclofen

Use of baclofen with other drugs that also depress the function of nerves may lead to additional reduction in brain function.

In addition to the risk of depressing brain function, the use of baclofen and tricyclic antidepressants (for example, amitriptyline [Elavil, Endep], doxepin [Sinequan, Adapin]) together may cause muscle weakness.

Use of baclofen and monoamine oxidase inhibitors (for example, phenelzine [Nardil], tranylcypromine or [Parnate]) can result in greater depression of brain function as well as low blood pressure.

Because baclofen can increase blood sugar, doses of antidiabetic drugs may need to be adjusted when baclofen is begun.

Skelaxin

Metaxalone has not been adequately studied in pregnant women.

It is not known whether metaxalone is excreted in breast milk. Safety for use in the nursing mother has not been established.

Baclofen

The use of baclofen by pregnant women has not been evaluated.