Eperisone Hydrochloride

Approved Indications:

• Muscle Spasticity:
• Symptomatic relief of increased muscle tone associated with spinal cord injuries, stroke, cerebral palsy, and other neurological disorders.
• Reduces muscle stiffness, spasms, and pain, improving mobility and daily function.
• Musculoskeletal Disorders:
• Relief of muscle pain, tension, and spasm associated with conditions such as cervical spondylosis, lumbago, and frozen shoulder.

Off-Label / Clinically Accepted Uses:

• Adjunctive therapy for postoperative muscle spasm.
• Management of tension-type headaches linked to cervical muscle spasm (limited evidence).

Adults:

• Typical oral dose: 50 mg three times daily after meals.
• Maximum daily dose: 150 mg.
• Tablets should be swallowed with water; avoid crushing or chewing.

Special Populations:

• Elderly: Usually no dose adjustment required, but monitor for excessive sedation or hypotension.
• Renal Impairment: Caution advised in severe impairment; dose reduction may be necessary.
• Hepatic Impairment: Use with caution; monitor liver function.

Pediatrics: Safety and efficacy not well-established; generally not recommended.

Duration: Short-term treatment recommended; reevaluate after 2–4 weeks for ongoing therapy.

Eperisone Hydrochloride is a centrally acting muscle relaxant. It reduces muscle tone by inhibiting spinal reflexes and motor neuron hyperactivity without significant sedation. It also causes vasodilation in skeletal muscles, improving local blood flow and reducing ischemia-related pain. These combined effects lead to decreased muscle stiffness, spasm, and pain, thereby enhancing mobility and functional capacity.

• Absorption: Well absorbed orally; peak plasma concentration in 1–2 hours.
• Bioavailability: Moderate; food slightly reduces rate but not extent of absorption.
• Distribution: Widely distributed; crosses the blood-brain barrier; moderate plasma protein binding (~80%).
• Metabolism: Extensively metabolized in the liver via hydroxylation and conjugation.
• Elimination: Excreted mainly in urine as metabolites.
• Half-Life: Approximately 1.5–2.5 hours.
• Onset of Action: Muscle relaxation observed within 30–60 minutes; peak effect 1–2 hours.

• Pregnancy: Safety not well established; use only if benefits outweigh potential risks. Animal studies show no major teratogenic effects at therapeutic doses.
• Lactation: Excreted in breast milk in small amounts; caution advised. Monitor infant for sedation or feeding difficulties.
• Data Limitations: Clinical studies in pregnant or breastfeeding women are limited; caution required.

• Primary Class: Muscle relaxant
• Subclass: Centrally acting, antispastic agent

• Known hypersensitivity to Eperisone Hydrochloride or any excipients.
• Severe hepatic impairment.
• Severe hypotension or cardiovascular instability.

• Hypotension: May cause mild hypotension due to vasodilatory effects; monitor blood pressure in sensitive patients.
• Sedation / Dizziness: Avoid driving or operating machinery until response is known.
• Liver Function: Rare hepatotoxicity reported; monitor in patients with pre-existing liver disease.
• High-Risk Groups: Elderly or debilitated patients may be more susceptible to dizziness, falls, or hypotension.

Common Adverse Effects:

• Central Nervous System: dizziness, headache, fatigue, mild drowsiness
• Gastrointestinal: nausea, epigastric discomfort
• Cardiovascular: mild hypotension

Serious or Rare Adverse Effects:

• Allergic reactions: rash, pruritus
• Liver enzyme elevation (rare)
• Very rare: severe hypotension or syncope

Timing and Severity:

• Usually mild to moderate; onset within the first few doses. Side effects often resolve with continued therapy or dose adjustment.

• Antihypertensives: May enhance hypotensive effects; monitor blood pressure.
• CNS Depressants / Alcohol: Additive sedation and dizziness possible; caution advised.
• Hepatic Metabolized Drugs: Minor potential for altered metabolism; clinical significance limited.
• Food: No significant food-drug interactions.

• Clinical Guidelines: Recommended as a first-line agent for symptomatic relief of muscle spasticity and pain in neurological and musculoskeletal disorders.
• Safety Updates: Reinforced caution in patients with hypotension and liver dysfunction.
• Regulatory Status: Widely approved in Asian and European countries; no major recent changes in dosing or indications.

• Temperature: Store at 20°C–25°C (68°F–77°F); short excursions 15°C–30°C permitted.
• Humidity & Light: Protect from moisture and direct light.
• Handling: Keep tablets in original container; do not crush or chew.
• Reconstitution: Not applicable; oral tablets ready for administration.