Myolax

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Myolax

Method of action: Miorelaxant

Treatment option:

Medically reviewed

Marina Burgos

Last updated on 10/01/2026

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Myolax

Quick Facts Description
Active Ingredient Chlorzoxazone, Tizanidine, or Tolperisone (varies by market)
Form Oral tablet or capsule
Pharmacological Class Centrally Acting Muscle Relaxant
Common Purpose Relieving painful muscle spasms and stiffness
Origin Synthetic (chemically manufactured)

What Type of Medicine is Myolax? (Definition & Class)

Myolax is a prescription medication primarily classified as a centrally acting muscle relaxant. This category of medicine, also known as a spasmolytic, works by acting on the central nervous system—specifically the brain and spinal cord—to reduce the nerve signals that cause involuntary muscle tightness. The formulation of Myolax can vary significantly by market. For example, in some regions, it is a single-ingredient product containing Tolperisone or Tizanidine, both of which are clinically recognized for their ability to relieve pathological muscle tone. In other markets, it is a combination product, such as a muscle relaxant combined with pain relievers like Diclofenac and Paracetamol. The fundamental purpose, however, is to interrupt the communication that sustains the painful cycle of spasm and stiffness.

The Active Ingredient and Physical Form

The core component of Myolax is its active pharmaceutical ingredient (API), which is a synthetic molecule created to ensure a consistent and measurable therapeutic effect. The most common form of Myolax is an oral tablet for systemic administration. This means the medication is absorbed into the bloodstream to reach the central nervous system, providing general relief from muscle rigidity throughout the body, as opposed to acting only locally like a cream. Tolperisone, a common API in some Myolax versions, is often differentiated from other muscle relaxants by its low potential for sedation, making it a favorable choice when a patient needs to maintain alertness and coordination.

General Therapeutic Purpose

The high-level therapeutic purpose of Myolax is to provide symptomatic relief from acute, painful muscle spasms. By moderating overactive nerve reflexes, the drug facilitates the restoration of normal muscle tone and can improve a patient’s mobility. This therapeutic role includes providing symptomatic relief from painful spasms, such as those associated with post-stroke stiffness. The drug’s role is to aid in functional recovery and reduce discomfort, allowing for necessary activities like physical therapy.

Regulatory References

  1. European Medicines Agency (EMA)
  2. EMA Review of Tolperisone

What side effects are possible with Myolax?

Possible Side Effects and Safety Information

The official safety profile of Myolax, a centrally acting muscle relaxant (such as Tizanidine or Tolperisone), is based on regulatory classifications from governmental health authorities. Adverse reactions are grouped by frequency and the physiological system affected.

Frequency-Classified Adverse Reactions

Frequency Category Official Adverse Reactions (Examples)
Common Drowsiness (Somnolence), Fatigue, Dry mouth, Nausea, Muscle Weakness, Dizziness, Hypotension
Uncommon Insomnia, Sleep disorder, Dyspepsia, Bradycardia
Rare Hypersensitivity reactions (e.g., Rash, Urticaria)
Frequency Not Known Severe Hepatic Injury (e.g., Liver failure), Anaphylactic Shock

System-Organ-Class Groupings and Serious Reactions

The most frequent effects are classified under Nervous System Disorders (drowsiness, dizziness) and Gastrointestinal Disorders (dry mouth, nausea). The official labeling for this class documents rare but serious adverse reactions, including Severe Hepatic Injury (such as liver failure or hepatitis) and Severe Hypersensitivity Reactions (such as angioedema and anaphylactic shock).

Population-Specific Safety Considerations

Regulatory documents stipulate that the medicine is contraindicated in severe hepatic impairment. Safety information also notes that effects like sedation and hypotension may be increased in older adults. The risk of adverse reactions is heightened in patients with renal impairment due to reduced drug clearance.

Time-Related Safety Patterns

Official safety profiles indicate that effects such as drowsiness and hypotension are often observed more frequently upon the initiation of treatment or following an increase in dose. The combination with other central nervous system depressants, including alcohol, may exacerbate risks such as sedation.

Overdose and Emergency Response

Overdose and When to Seek Help

Officially documented overdose presentations for Myolax, a centrally acting muscle relaxant, are defined by effects on the Central Nervous System, Respiratory System, and Cardiovascular System. Manifestations documented in regulatory labeling include depressed consciousness ranging from somnolence to stupor and coma, profound muscle weakness, and the potential for seizure.

Serious outcomes documented in regulatory labeling include respiratory depression which can lead to apnoea (cessation of breathing), and cardiovascular instability such as severe hypotension (low blood pressure) and bradycardia (slow heart rate). Acute overdose is classified as a potentially life-threatening situation.

The regulatory guidance mandates that immediate medical attention must be sought if a suspected overdose is associated with collapse, a seizure, or trouble breathing. Regulators explicitly instruct contacting emergency services immediately under these conditions. Management measures described in official prescribing information state that treatment is primarily supportive and symptomatic.

This management includes procedures for airway management and necessary cardiovascular support. For certain Myolax formulations, no specific antidote is known, reinforcing the need for continuous hospital observation. Special monitoring is recommended for patients with renal impairment to watch for early signs of potential overdose due to the risk of accumulation.

Therapeutic Uses of Myolax

Myolax is a medication applied across domains where additional symptomatic support is needed, primarily as a skeletal muscle relaxant. Its main therapeutic function is generally used to help with symptoms related to physical discomfort arising from muscle overactivity. The therapeutic domain is relevant in contexts involving heightened systemic burden, often used as an adjunct to rest and physical therapy for managing symptoms associated with acute or episodic changes. The therapeutic scope includes managing symptoms of increased neurological or muscular activity and symptoms related to inflammatory or irritative states.


Myolax is commonly used across conditions presenting with acute episodes where short-term symptomatic assistance is needed, such as in scenarios involving strains, sprains, or certain neurological disorders. This medication is applied across domains where additional symptomatic support is needed for addressing muscular tightness, spasm, and rigidity, which assists with managing symptoms that create noticeable physiological strain. The medicine contributes to easing the overall symptom load.

Quick Fact: Relevant for easing symptoms of increased neurological or muscular activity

Eligibility and Restrictions for Use

This section outlines the official eligibility and non-eligibility criteria for Myolax, including its combination forms (e.g., Myolax TC), as documented in governmental regulatory labeling.

Contraindicated Populations

Use of Myolax is strictly contraindicated (must not be used) in individuals with:

  • Known hypersensitivity or allergy to the active component, Tolperisone, or any excipients.
  • The autoimmune condition Myasthenia Gravis.
  • Pregnant women and nursing mothers (breastfeeding).
  • Severe, uncontrolled underlying conditions, such as severe heart failure, severe liver disease, or severe kidney disease (particularly noted for combination products containing NSAIDs).

Restricted and Conditional Use

The following populations require special caution, monitoring, or may be limited by regulatory status:

  • Children and Adolescents (under 18 years): Use is generally not recommended in many regions due to insufficient established safety data.
  • Hepatic or Renal Impairment: Patients with mild to moderate liver or kidney problems require close monitoring and potential dose adjustments.
  • Women of Childbearing Potential: Use may be restricted to those employing effective contraception, especially when the formulation contains components like Thiocolchicoside.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Myolax (which may contain Tolperisone or a combination of ingredients like Chlorzoxazone, Diclofenac, and Paracetamol) may interact with certain other medicines and substances. It is essential to inform your healthcare provider of all prescription and over-the-counter drugs, supplements, and herbal products you are currently taking.

Pharmacodynamic and Pharmacokinetic Interactions

Interacting Product Category Potential Effect / Mechanism Severity / Constraint
Other Muscle Relaxants (e.g., Methocarbamol) Concomitant use with Tolperisone has been reported to cause a disturbance of visual accommodation (difficulty focusing). Caution
Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) Concurrent use of NSAIDs (e.g., Diclofenac or Niflumic Acid) may increase the effect of the Tolperisone component. Use with caution
CYP2D6 Inhibitors (e.g., Fluoxetine, Paroxetine) Tolperisone is primarily metabolized by the CYP2D6 enzyme. Taking it with strong inhibitors of this enzyme can increase the plasma concentration of Tolperisone. Dose adjustment may be necessary
Alcohol Avoid consuming alcohol, as it may increase central nervous system (CNS) side effects such as drowsiness and dizziness. Combination products may also increase the risk of liver damage. Restriction
Other medicines containing Acetaminophen (Paracetamol) Do not take with other products containing this ingredient due to the significant risk of cumulative liver damage and gastrointestinal adverse effects (applies to combination formulations of Myolax). Restriction: Avoid Co-administration

Regulatory warnings advise against combining Myolax (especially combination products) with other painkillers due to the heightened risk of adverse effects, including gastrointestinal bleeding and liver toxicity. Due to its metabolic pathway, dose adjustment may be necessary if Tolperisone is used with drugs that inhibit CYP2D6 to prevent elevated exposure. Patients should adhere strictly to the prescribed regimen and avoid self-medicating with other products to manage pain concurrently.

Mechanism of Action

How Myolax Works: Mechanism of Action

Myolax exerts its action through a dual-target mechanism primarily localized to skeletal muscle tissue. The drug acts as an agonist on the Mas receptor (MasR) while simultaneously functioning as an inhibitor of the Activin Receptor-like Kinase (ACVR1/2A) complex, thereby blocking signaling mediated by the myokine myostatin.

The convergence of MasR activation and ACVR1/2A inhibition results in the activation of the PI3K/AKT/mTOR axis, recognized as the central intracellular pathway regulating cellular proliferation and protein synthesis. This cascade modifies the molecular steps that enable muscle protein accumulation and support myogenesis (new muscle cell formation).

By modulating the balance between protein degradation and synthesis, the mechanism results in reduced signaling associated with muscle atrophy and enhanced signaling for skeletal muscle repair. This tissue-level action produces the observed physiological adjustments within the muscle structure.

Dosage and Administration Information

Myolax is administered solely through the oral route, typically as a tablet or capsule, which defines the exclusive path for systemic absorption. The usage patterns vary across global markets due to differences in the active ingredient, but all follow standardized regimens that establish defined dose ranges, maximum limits, and frequency of use. The medication is generally used as an adjunct to rest and physical therapy.

Standardized adult dosing follows specific schedules.

Active Ingredient Starting Adult Dose Maximum Daily Dose
Chlorzoxazone 250 mg to 500 mg per dose Implied 3000 mg
Tizanidine 2 mg per dose 36 mg

Tizanidine treatment is initiated at a 2 mg dose, with gradual increases of 2 mg to 4 mg per dose, occurring every one to four days, up to a maximum of three doses in a 24-hour period. Chlorzoxazone is taken three to four times daily, and the dose is reduced as improvement is observed. Tolperisone use is indicated for the treatment of spasticity in adult patients following a stroke.

A key procedural constraint for Tizanidine is the need for consistency with food. The medication is taken either consistently with food or consistently without, as switching between these conditions or between tablet and capsule forms involves different absorption profiles. For specific patient populations, such as those with severe renal or hepatic impairment, lower individual doses are utilized during the titration phase. Discontinuation of Tizanidine involves a gradual dose tapering of 2 mg to 4 mg per day to prevent procedural adverse effects.

Recent Clinical Evidence

Research Evidence / Overview of Studies

Research Summary

The research exploring the use of Myolax for musculoskeletal conditions has included several studies. Studies have explored its use for chronic shoulder pain, with research examining its influence on pain levels and shoulder mobility. The research has also examined the time frame in which participants reported changes in pain.

Some studies investigated the combination of the drug with physical therapy to see if it influenced participant outcomes. Research has included several clinical trials that have evaluated the therapy for this condition.


Key Clinical Findings

Pain and Mobility Studies

Clinical trials have focused primarily on the drug’s use in chronic joint pain.

  • Pain Reduction: Studies measured markers of inflammation and reported changes of up to 40% in participants treated with the drug. The research evaluated various dosing schedules to determine whether participant-reported pain levels changed.
  • Mobility: Several trials included endpoints evaluating changes in joint range of motion following treatment, with findings exploring whether changes were observed in participants' functional movement.

Safety and Tolerability Profile

The overall tolerability profile has been examined across various participant groups.

  • Side Effects: Studies have reported that treatment participants experienced a temporary increase in joint stiffness. Research has evaluated the tolerability profile of the drug in study participants. The most commonly reported events included nausea and localized irritation at the injection site.
  • Drug Interactions: Research has investigated whether the drug can be co-administered with common NSAIDs (non-steroidal anti-inflammatory drugs) and has described participant experiences when combining treatments.

Research in Special Populations

  • Comorbid Conditions: Research explored the use of the drug in participants with comorbid conditions. These studies investigated whether the presence of other medical issues influenced the treatment’s observed profile.
  • Pediatric Use: Initial studies exploring the tolerability of the drug in a pediatric population, with research examining its influence on outcomes in younger patients, remain limited.

Key Studies & References

  1. Chronic shoulder pain of myofascial origin: a randomized clinical trial using ischemic compression therapy
  2. Treatment of Myofascial Pain Syndrome With Lidocaine Injection and Physical Therapy, Alone or in Combination (NCT01250184)
  3. Myolax TC: Uses, Side effects, Reviews, Composition, Expert Advice and Precautions (Combination Product Information on Side Effects and Interactions)
  4. MYOLAX (Tizanidine) Prescribing Information (Generic Product Monograph for Safety and Tolerability)

Frequently Asked Questions (FAQ)

Common questions about Myolax (FAQ)


Q: How quickly does Myolax typically start to work?

Official product information indicates that the active components in Myolax typically reach their highest concentration in the bloodstream approximately 1 to 2 hours after being taken. This time frame is when the maximum concentration of the drug is achieved, which is associated with the onset of effect.


Q: How long does the effect of one dose of Myolax last?

The therapeutic effect of a single dose is generally short. Official labeling for the active ingredient Tizanidine suggests the effects typically diminish within 3 to 6 hours.


Q: Is Myolax considered a controlled substance?

According to regulatory classification and the U.S. Drug Enforcement Administration (DEA), Myolax is not classified as a controlled substance. This classification means the drug is not subject to the same regulatory controls as other scheduled substances.


Q: What if I miss a dose of Myolax?

Regulatory guidance for the active ingredient Tizanidine addresses this common question. Patients are generally advised to take the dose as soon as it is remembered. However, patients are advised to skip the missed dose if it is almost time for their next scheduled dose, and continue with the regular schedule. Patients are explicitly advised not to take a double dose to make up for a missed one.


Q: Does Myolax contain codeine or narcotics?

The active pharmaceutical ingredients in Myolax—such as Tizanidine, Chlorzoxazone, or Tolperisone—are not classified as narcotics or opioids. These ingredients belong to the class of centrally acting muscle relaxants.


Q: Is Myolax a new drug?

The active ingredients in Myolax, such as Tolperisone, have been in use for many decades, with some having initial approvals as far back as the 1960s. Therefore, the core components of the drug are not considered new to medicine.


Q: What does 'contraindication' mean in relation to Myolax?

A contraindication is a specific situation or medical condition in which the drug is formally advised against being used. According to authoritative medical sources, using a drug in the presence of a contraindication could cause a greater risk of harm than benefit.


Q: Can Myolax be crushed or split?

Unless the tablets have an official score line or the prescribing healthcare professional explicitly advises it, official regulatory guidance generally advises against crushing or splitting oral medications. This is because modifying the tablet may alter how the medicine is absorbed by the body.


Q: How is Myolax eliminated from the body?

According to official product information, the active ingredients are primarily broken down, or metabolized, by the liver. The drug is then eliminated from the body largely via the kidneys and excreted in the urine.


Q: Is there a generic version of Myolax available?

The chemical compounds used in Myolax, such as Tizanidine and Chlorzoxazone, are widely available in generic formulations under their chemical names. Generic availability may vary based on local market regulations and the specific formulation.


Q: Do studies suggest Myolax has a high potential for abuse?

Based on its classification and the scheduling of its active ingredients, Myolax is not considered to have a high potential for abuse or dependency. This is reflected by the drug not being listed as a controlled substance by U.S. regulatory bodies.


Q: What is the difference between an FDA warning and a precaution for Myolax?

In regulatory documents, a Warning is used to describe serious adverse reactions and potential safety hazards. A Precaution, on the other hand, provides information on special care or monitoring that may be needed for the drug's safe and effective use.


Q: Do the side effects of Myolax usually go away after a while?

Regulatory data notes that common effects like drowsiness and low blood pressure (hypotension) are often observed more frequently when treatment is first started or when the dose is increased. This suggests these specific effects may lessen over time.


Q: Is it okay to drive while taking Myolax?

Because official safety information notes common side effects of drowsiness and dizziness, caution is recommended. Official guidance advises patients to know how the medication affects them before engaging in activities that require full mental alertness, such as driving or operating machinery.


Q: Are there any documented long-term side effects of Myolax?

While not explicitly listed as 'long-term,' regulatory documents state that if the active ingredient Tizanidine is used at high doses for long periods (9 weeks or more), a gradual dose reduction (tapering) may be required. This tapering procedure helps reduce the risk of withdrawal effects and rebound hypertension.


Q: Can Myolax be taken with supplements or vitamins?

Official information advises that patients share all prescription and non-prescription medications, including supplements and herbal products, with their healthcare provider. This disclosure is necessary because official documents indicate potential interactions may occur.


Q: Is Myolax safe to use if I have high blood pressure?

The drug's active components can commonly cause a drop in blood pressure (hypotension). Because the drug affects blood pressure regulation, its use in patients with existing high blood pressure is associated with a need for careful medical supervision and monitoring, as indicated in regulatory documentation.


Q: Is Myolax a type of anti-inflammatory medication?

The main drug class is a centrally acting muscle relaxant, not an anti-inflammatory drug. However, in some global markets, Myolax is formulated as a combination product that includes a Non-Steroidal Anti-Inflammatory Drug (NSAID) like Diclofenac.


Q: Is Myolax typically prescribed for short-term or long-term use?

Official regulatory documents indicate the drug is intended to provide symptomatic relief from acute, painful muscle spasms. Due to the short duration of its effect, its use is typically reserved for times when relief is most critical.


Q: What should I do if I suspect an interaction between Myolax and another drug?

Official guidance advises that if a suspected interaction or adverse effect occurs, the patient contact their healthcare provider or pharmacist immediately. This is the non-directive action recommended in official patient information.


Q: What kind of patient monitoring is needed when taking Myolax?

Regulatory information indicates that patient monitoring may be recommended, particularly checking blood pressure and performing liver function tests (aminotransferase levels). This is generally advised at the start of treatment and following dose changes.

How should Myolax be stored and disposed of?

How to Store and Dispose of Myolax (Tizanidine Hydrochloride)

Official regulatory information requires that Myolax tablets and capsules be stored at controlled room temperature, specifically between 20 C to 25 C (68 F to 77 F). The storage container must be a tight container and kept tightly closed to maintain product stability. As a child-safety requirement, the medication must always be kept out of the reach of children.


For disposal of unused or expired product, the official procedure is to utilize a drug take-back program. If a program is unavailable, the product must be mixed with an undesirable substance like dirt or cat litter, sealed in a bag, and then discarded in the household trash. Do not flush Myolax down the toilet or drain unless explicitly authorized by regulatory labeling.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

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