Skelaxin vs Zanaflex

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For patients experiencing muscle spasms or related discomfort, certain drugs that block nerve impulses sent to the brain can help in managing these symptoms. Skelaxin (metaxalone) and Zanaflex (tizanidine) are two such drugs often prescribed for this purpose. They each function differently but both have a significant effect in alleviating muscular discomfort. Skelaxin is classified as a skeletal muscle relaxant that primarily works by blocking nerve impulses in the brain, effectively reducing pain sensations. On the other hand, Zanaflex is an alpha-2 adrenergic agonist that decreases spasticity by slowing action potentials thereby inhibiting presynaptic motor neurons.

What is Skelaxin?

Metaxalone (the generic name for Skelaxin) and Tizanidine (the generic name for Zanaflex) are muscle relaxants prescribed primarily to manage discomfort associated with acute, painful musculoskeletal conditions. Metaxalone, first approved by the FDA in 1962, functions by blocking nerve impulses in the brain that lead to muscle spasms. It is taken orally as tablets and does not directly act on skeletal muscles; instead, it acts centrally (in the brain).

On the other hand, Tizanidine was approved later - in 1996 - and works by increasing alpha-2-adrenergic inhibition which reduces spasticity. It is often used for treating spasticity resulting from issues like multiple sclerosis or spinal cord injury. The drug's impact mainly focuses on alpha-2-adrenergic receptors with only minor influence on histamine or acetylcholine receptors leading to fewer side effects compared to other drugs that have a broader receptor activity spectrum.

What conditions is Skelaxin approved to treat?

Skelaxin and Zanaflex are both approved for the treatment of muscle conditions:

  • Skelaxin is used to relax muscles and relieve pain caused by sprains, strains, and other musculoskeletal conditions.
  • Zanaflex is primarily used in the management of spasticity due to cerebral or spinal injury. It helps reduce stiffness, tightness, or restriction that can occur with these conditions.

How does Skelaxin help with these illnesses?

Skelaxin, known as Metaxalone in its generic form, alleviates muscle spasms by blocking nerve impulses (or pain sensations) that are sent to the brain. This drug does not act directly on skeletal muscle, but rather it interrupts neural communication between the spinal cord and brain. It's often prescribed for individuals dealing with painful musculoskeletal conditions such as sprains, strains or other muscle injuries.

On the other hand, Zanaflex (Tizanidine) is a central alpha-2-adrenergic agonist which diminishes spasticity without reducing muscle tone. It works by slowing action in the nervous system to allow muscles to relax thereby easing painful and uncomfortable muscle spasms caused by certain medical conditions like multiple sclerosis or spinal injury.

Both Skelaxin and Zanaflex work differently so their choice depends on individual patient needs and responses. Always consult your healthcare provider before choosing these medications.

What is Zanaflex?

Zanaflex, the brand name for tizanidine, is a short-acting muscle relaxer that works by blocking nerve impulses (pain sensations) sent to your brain. It's primarily prescribed for individuals with Multiple Sclerosis or spinal cord injuries. Approved by the FDA in 1996, Zanaflex operates differently from most other drugs used to treat spasticity. Instead of being a direct muscle relaxant, it’s an alpha-2 adrenergic agonist which inhibits the release of substance P in the CNS and increases presynaptic inhibition at spinal interneurons.

Zanaflex does not have serotonin reuptake inhibition properties like some antidepressants such as Prozac; hence its side effect profile differs significantly from those types of medications. Common side effects include dry mouth and drowsiness but less likely weight gain and sexual dysfunction compared to SSRIs like Prozac. Its unique mechanism can be beneficial especially for patients who do not respond well or cannot tolerate typical muscle relaxants such as Skelaxin.

What conditions is Zanaflex approved to treat?

Zanaflex is a medication that has been approved for the management of:

  • Spasticity, which can occur in conditions like multiple sclerosis or spinal cord injury
  • Certain types of muscle stiffness and spasms

This makes Zanaflex particularly useful to those who need help managing these specific symptoms linked to their medical condition.

How does Zanaflex help with these illnesses?

Zanaflex, like Skelaxin, is a muscle relaxant used to alleviate symptoms of muscle spasms and tightness. This drug works by blocking nerve impulses (pain sensations) sent to your brain. Zanaflex's effect on the alpha-2-adrenergic receptor in the central nervous system helps reduce spasticity by temporarily relaxing muscle tone. It differs from other anti-spasmotic medicines as it has a greater impact on your central nervous system rather than directly working on skeletal muscles.

Due to its potential for lowering blood pressure, Zanaflex is often prescribed when there are contraindications or lack of response with typical muscle relaxants like Skelaxin. However, due to its sedative effects, this medication should be taken under careful monitoring.

How effective are both Skelaxin and Zanaflex?

Both metaxalone (Skelaxin) and tizanidine (Zanaflex) have established histories of success in treating muscle spasms, with their FDA approvals coming just a few years apart. As they operate through different mechanisms, they may be prescribed under different circumstances. Metaxalone acts as a muscle relaxant by affecting the central nervous system and relaxing muscles, while tizanidine is an alpha-2 adrenergic agonist that reduces spasticity by temporarily relaxing muscle tone.

The effectiveness of metaxalone and tizanidine in alleviating muscle spasms has been studied directly in several clinical trials. These studies found similar efficacy between the two drugs for managing musculoskeletal conditions such as back or neck pain; however, side effect profiles varied significantly. Tizanidine was more likely to cause drowsiness and dry mouth but less likely to result in nausea compared to metaxalone.

A review conducted on metaxalone concluded that it provides effective relief from acute musculoskeletal pain due its central muscle relaxant properties without many of the detrimental side effects associated with other comparable medications like sedation or addiction potential. However, it's important to note optimal dosing varies depending on patient weight and metabolism speed.

For tizanidine, research indicates its effectiveness beyond placebo for reducing spasticity related symptoms thereby improving functionality among patients suffering from multiple sclerosis or spinal cord injury where these symptoms are often prevalent. It's also used off-label for migraines due to its ability to reduce muscular tension linked with these headaches. Nonetheless, usage should be carefully monitored due to reported cases of liver damage when used long-term at high doses.

abstract image of a researcher studying a bottle of drug.

At what dose is Skelaxin typically prescribed?

Oral dosages of Skelaxin typically start at 800 mg, taken three to four times per day. However, studies have shown that this dosage is usually effective for treating muscle spasms in most people. For Zanaflex, the starting dose is often 2 mg, and can be increased gradually — by your healthcare provider's recommendation — if there is no response. In either population using these medications, it's crucial to closely follow the prescribed dosage instructions given by a physician or pharmacist. The maximum daily dosage for Skelaxin should not exceed 3200 mg/day and for Zanaflex should not go beyond 36 mg within a period of 24 hours.

At what dose is Zanaflex typically prescribed?

Zanaflex treatment typically begins at a dosage of 2 mg/day. The dose can then be increased gradually in increments of 2-4 mg, with careful monitoring for side effects. The doses are usually given up to three times per day, spaced evenly throughout the day. A maximum dose of 36 mg/day divided into three separate doses may be reached and evaluated if there is no response to treatment after several weeks. As always, dosages must be personalized for each patient based on individual therapeutic responses and tolerability.

What are the most common side effects for Skelaxin?

The most commonly reported side effects of Skelaxin (metaxalone) include:

  • Drowsiness or somnolence
  • Dizziness
  • Headache
  • Nervousness or irritability
  • Nausea, vomiting, and digestive upset
  • A decreased appetite

On the other hand, Zanaflex (tizanidine) can cause some overlapping but also distinct side effects such as:

  • Dry mouth
  • Weakness/fatigue or asthenia
  • Somnolence (sleepiness/drowsiness)
  • Hypotension (low blood pressure)
  • Liver function test abnormalities

Always consult with a healthcare provider to understand potential side effects before starting any new medication.

abstract image of a patient experiencing side effect

Are there any potential serious side effects for Skelaxin?

While Zanaflex is generally considered safe, it can in rare cases cause serious side effects such as:

  • Allergic reactions like hives, swelling in your face or throat, difficulty breathing
  • Unusual thoughts or behavior: hallucinations (seeing things), anxiety, feeling lightheaded or fainting
  • Yellowing of the skin and eyes indicating liver problems
  • Changes in heart rhythm – fast or pounding heartbeats
  • Low blood pressure - blurry vision, headache, buzzing in your ears
  • High levels of white blood cells - fever with sore throat and burning when you urinate; also pale skin with rash and bruising could indicate this condition.

In extreme cases one might experience nervous system issues such as severe drowsiness/feeling very weak or tired. If any of these symptoms occur after taking Zanaflex seek immediate medical attention.

What are the most common side effects for Zanaflex?

Zanaflex, like any other medication, has its unique set of potential side effects. Some individuals may experience:

  • Dry mouth or throat
  • Fatigue or weakness
  • Dizziness and lightheadedness
  • Stomach pain, nausea, or constipation
  • Sleep disturbances such as insomnia
  • Increased muscle tone causing tremors
  • Anxious feelings and nervousness
  • Hypotension (low blood pressure) leading to a faster heart rate
  • Mood changes including confusion or agitation
  • Skin rash or itching -Unexplained weight loss
    -Increased frequency of urination
    -Persistent headache
    -Muscle stiffness and joint pain

Are there any potential serious side effects for Zanaflex?

Zanaflex, like all medications, can potentially cause side effects. Some of these include:

  • Signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue or throat
  • A light-headed feeling as if you might pass out
  • Slow heart rate or low blood pressure causing dizziness
  • Dry mouth or a sore throat
  • Urination problems such as burning sensation during urinating or less than usual urine output
  • Liver damage symptoms such as nausea and stomach pain, loss of appetite, dark urine coloration and jaundice (yellowing of the skin and eyes)

If you're on Zanaflex and experience any unusual changes in behavior, mood swings, confusion or hallucinations ensure to consult with your healthcare provider promptly. Although side-effects like blurred vision are not common with Zanaflex use if they do occur it's important to seek medical advice at once.

Contraindications for Skelaxin and Zanaflex?

Both Skelaxin and Zanaflex, like most other muscle relaxants, may worsen symptoms of depression in some individuals. If you notice your mood worsening or an increase in suicidal thoughts or behavior after starting on either medication, please seek immediate medical attention.

Neither Skelaxin nor Zanaflex should be taken if you are taking, or have recently been taking monoamine oxidase (MAO) inhibitors. Always inform your physician about any medications you are currently using; MAOIs will require a period of about 2 weeks to clear from the system to prevent dangerous interactions with both Skelaxin and Zanaflex.

How much do Skelaxin and Zanaflex cost?

For the brand name versions of these drugs:

  • The price of 30 tablets of Skelaxin (800 mg) averages around $300, which works out to approximately $10/day.
  • The price for 30 tablets of Zanaflex (4mg) is about $80, working out to roughly $2.67/day.

Thus, if you're taking a standard dosage range for Skelaxin (i.e., 1600–3200 mg/day), then brand-name Zanaflex can be less expensive on a per-day treatment basis. Please note that cost should not be your primary consideration in determining which drug is right for you.

For the generic versions of Skelaxin (metaxalone) and Zanaflex (tizanidine), costs are significantly lower:

  • Metaxalone is available in packs from 15 up to 180 capsules with the cost starting from as low as $0.50/day and going up to about $1.00/day depending on how many are bought upfront and the specific dose.
  • Tizanidine comes in packs ranging from 20 up to even larger quantities with daily costs running between just under a dime ($0.08) when buying large quantities upfront at lower doses up through approximately fifty cents ($0.50).

Popularity of Skelaxin and Zanaflex

Metaxalone, in generic form as well as brand names such as Skelaxin, was estimated to have been prescribed to about 2.5 million people in the US in 2020. Metaxalone accounted for just over 8% of muscle relaxant prescriptions in the US. It appears to be a popular choice among skeletal muscle relaxants and has seen steady usage over the past few years.

Tizanidine, including brand versions like Zanaflex, was prescribed to around 3 million people in the USA during the same period. In terms of overall muscle relaxant prescriptions within the country, Tizanidine accounts for nearly 10%. The prevalence of tizanidine has slightly increased over time due to its effectiveness and tolerability compared with other drugs used for similar purposes.


Both Skelaxin (metaxalone) and Zanaflex (tizanidine) are regularly used in patients with muscle spasms, and there is a wealth of clinical data supporting their efficacy over placebo treatments. Occasionally, the drugs may be used together but this requires careful oversight by a physician as they can interact negatively. They have different mechanisms of action: Skelaxin's exact mechanism isn't fully understood but it is thought to work centrally in the brain while Zanaflex acts on alpha-2-adrenergic receptors.

Skelaxin is often considered a first-line treatment option for muscle relaxation due to its lower propensity for drowsiness compared to other muscle relaxants. Conversely, Zanaflex would usually be considered as an addition when other treatments fail or when sedation could be beneficial such as when sleep disturbance co-exists due to pain.

Both medications are available in generic form which makes them more affordable particularly for those who must pay out of pocket. The period required before noticing effects from both Skelaxin and Zanaflex varies between individuals.

The side effect profiles of these two drugs vary slightly despite both being generally well-tolerated; dizziness and dry mouth are common with Zanaflex whereas nervousness and irritability tend to occur less frequently than with Skelaxin. For both drugs, patients must closely monitor their condition especially upon starting treatment, seeking medical advice promptly if symptoms persist or worsen.