Myolax Plus

Approved Indications:

• Acute Musculoskeletal Pain:
  Used for the relief of acute pain and muscle spasm associated with musculoskeletal conditions.
• Muscle Spasticity:
  Indicated in the management of skeletal muscle spasticity due to neurological conditions such as multiple sclerosis, cerebral palsy, spinal cord injuries, and post-stroke states (mild to moderate severity).
• Cervical and Lumbar Spondylosis:
  Relieves pain and stiffness associated with degenerative spine disorders.
• Postoperative Muscle Spasms:
  Used adjunctively to reduce muscle spasm and pain following orthopedic surgeries.
• Myofascial Pain Syndrome:
  Provides symptomatic relief of localized muscle spasm and trigger point pain.

Off-label/Clinically Accepted Use:

• Fibromyalgia-related Muscle Spasm:
  Occasionally used for managing chronic muscle pain and stiffness in fibromyalgia, although not a first-line agent.

Route of Administration:
Oral (film-coated tablet)

Recommended Adult Dose:

• Standard dose: Tolperisone 150 mg + Lidocaine 50 mg, orally twice or thrice daily, preferably after meals.
• Titration: Start with a lower dose if needed and titrate based on patient response and tolerability.
• Duration: Generally prescribed for 7–14 days depending on the condition.

Pediatric Use:

• Not recommended in children below 18 years due to lack of adequate safety data.

Elderly:

• Dose should be used cautiously; begin at the lowest effective dose due to potential for altered hepatic or renal function.

Renal or Hepatic Impairment:

• Use with caution. No specific dose adjustment available, but clinical monitoring is advised.

Missed Dose:

• If a dose is missed, take it as soon as possible unless it’s near the time for the next dose. Do not double the dose.

Tolperisone is a centrally acting muscle relaxant that acts by blocking voltage-gated sodium and calcium channels in the spinal reflex arcs. It inhibits mono- and polysynaptic reflex transmission in the spinal cord and subcortical areas, reducing muscle tone and spasticity without significant sedation.
Lidocaine is a local anesthetic of the amide type that stabilizes neuronal membranes by inhibiting sodium influx, preventing the initiation and conduction of nerve impulses. When combined, Tolperisone relieves muscle stiffness while Lidocaine offers local pain relief at the muscular level, contributing to the overall analgesic effect.

Tolperisone:

• Absorption: Well absorbed orally; peak plasma concentration reached in 30–60 minutes.
• Bioavailability: Moderate due to first-pass metabolism.
• Distribution: Widely distributed; crosses the blood-brain barrier.
• Metabolism: Extensively metabolized in the liver, primarily via CYP enzymes.
• Half-life: Approximately 2–2.5 hours.
• Excretion: Renal, as metabolites.

Lidocaine:

• Absorption: Rapid absorption; systemic exposure depends on dose and tissue vascularity.
• Distribution: Binds extensively to plasma proteins; crosses placenta and blood-brain barrier.
• Metabolism: Primarily metabolized in the liver via CYP1A2 and CYP3A4 to active and inactive metabolites.
• Half-life: Approximately 1.5–2 hours (can vary with hepatic impairment).
• Excretion: Renal, mostly as metabolites.

Pregnancy:

• FDA Pregnancy Category: Not officially classified; both drugs lack sufficient well-controlled studies in pregnant women.
• Tolperisone: Animal studies suggest no teratogenicity, but safety in human pregnancy is not established.
• Lidocaine: Generally considered safe for short-term use in pregnancy (Category B), especially when used locally.

Lactation:

• Lidocaine is excreted in breast milk in low concentrations; generally considered compatible with breastfeeding.
• Tolperisone: Insufficient data available; use only if benefit outweighs potential risk.
• Recommendation: Use with caution in nursing mothers.

• Primary Class: Centrally Acting Muscle Relaxant with Local Anesthetic
• Subclass:
• Tolperisone: Centrally acting skeletal muscle relaxant (piperidine derivative)
• Lidocaine: Amide-type local anesthetic and Class 1B antiarrhythmic agent

• Known hypersensitivity to Tolperisone, Lidocaine, or any excipients
• Myasthenia gravis
• Severe hepatic impairment
• Severe renal impairment
• Heart block or cardiac arrhythmia (specific to Lidocaine)
• History of seizures or epilepsy (use with caution)

• Seizure Risk: Lidocaine may lower the seizure threshold, especially at high systemic levels.
• Liver Disease: Monitor liver function in patients with hepatic impairment.
• Renal Disease: Dose adjustment or avoidance may be necessary.
• Cardiac Conduction Disorders: Lidocaine can cause arrhythmias or heart block.
• Drowsiness/Dizziness: Patients should avoid driving or operating heavy machinery.
• Hypersensitivity Reactions: Rare but can be serious; discontinue immediately if symptoms occur.
• Use in Elderly: Monitor closely due to increased risk of CNS or cardiac side effects.

Common Adverse Effects:

• Central Nervous System: Dizziness, drowsiness, headache, fatigue
• Gastrointestinal: Nausea, vomiting, dyspepsia, dry mouth
• Musculoskeletal: Muscle weakness, tremors
• Cardiovascular: Hypotension, bradycardia (rare with Lidocaine)

Serious/Rare Side Effects:

• Anaphylaxis, angioedema (hypersensitivity)
• Seizures (especially with high doses of Lidocaine)
• Cardiac arrhythmia, heart block
• Liver enzyme elevation
• Severe skin reactions (rash, Stevens-Johnson Syndrome – extremely rare)

Onset/Severity:

• Onset of CNS side effects can be early; most are mild and dose-dependent.

• With CNS Depressants: Additive sedation with alcohol, benzodiazepines, opioids.
• With Antiarrhythmics (e.g., amiodarone, mexiletine): Risk of additive cardiac effects.
• With CYP3A4 or CYP1A2 inhibitors (e.g., erythromycin, fluoxetine): May increase Lidocaine plasma concentration.
• With Beta-blockers: May enhance the hypotensive effect of Tolperisone.
• Alcohol: Increases risk of sedation and CNS depression.

Enzyme Systems Involved:

• Lidocaine: Metabolized by CYP1A2 and CYP3A4
• Tolperisone: Likely CYP-mediated hepatic metabolism

• Recent Formulation Approvals: Combination formulations of Tolperisone + Lidocaine have been approved in some countries (e.g., India, Bangladesh) for short-term relief of muscle spasms.
• Regulatory Recommendations: Emphasis on short-term use only; no long-term efficacy or safety data established.
• Guideline Positioning: Not included in major international guidelines due to lack of large-scale RCTs, but widely used in clinical practice for symptomatic relief.

• Temperature: Store below 25°C (77°F)
• Humidity: Protect from moisture; store in a dry place
• Light: Keep away from direct sunlight
• Handling: Store in original blister pack; do not use if tablet is discolored or damaged
• Reconstitution/Refrigeration: Not applicable; oral tablet formulation