How Many Types of Muscle Relaxants? Which to Choose

How many types of Muscle Relaxants are there?

Muscle relaxants are pharmacologically divided into 3 major groups based on mechanism of action — each used for distinctly different conditions:

1. Antispasmodics (short-term use muscle relaxants) — act on the central nervous system to reduce muscle spasm signals from acute injury. The most commonly used group in pharmacies and general clinics — back pain, neck strain, shoulder tension all use this group.
2. Antispastics (muscle relaxants for neurological conditions) — act on the spinal cord or brain, used for chronic muscle spasticity from conditions like stroke, multiple sclerosis, cerebral palsy — always require specialist physician supervision.
3. Direct-acting (act directly on muscle tissue) — e.g. Dantrolene, rarely used in Thailand, mainly for malignant hyperthermia or severe spasticity.

The group most people encounter at the pharmacy is Antispasmodics, which has 4-5 main drugs, each with different strengths. We will cover each one in detail in this article.

📖 Read more: See the complete muscle relaxant overview — usage, side effects, precautions at Muscle Relaxants — Complete Guide

Tolperisone — The Most Popular Muscle Relaxant in Thailand

What is Tolperisone?

Tolperisone is an Antispasmodic muscle relaxant widely used in Thailand. It acts on the central nervous system, particularly the brainstem and spinal cord, reducing muscle spasm signals without strong CNS sedation like sleeping pills.

Mechanism of Action

Tolperisone works by blocking sodium and calcium channels in spinal cord neurons, reducing muscle spasm signals. The result is muscle relaxation without significantly affecting consciousness — making it less sedating than Orphenadrine.

Common Doses

• 50 mg — starting dose for mild to moderate symptoms, taken 2-3 times/day after meals
• 150 mg — for more severe symptoms, or when 50 mg is insufficient

Brands in Thailand

• Mydocalm — original brand from Sanofi/Gedeon Richter (Europe), the doctor-preferred standard
• Biocalm — manufactured in Thailand, same active ingredient at 50 mg, an affordable alternative
• Soneriper M, Sotolper, Tolper — other available brands

What is Soneriper M?

Soneriper M contains Tolperisone HCl 50 mg + Methylcobalamin (Vitamin B12) 0.5 mg in one tablet. The "M" stands for Methylcobalamin — which helps repair inflamed nerves. Often prescribed together when back pain involves nerve compression, or for numbness in arms and legs.

Notable Side Effects

• Nausea, headache, mild drowsiness — common but not severe
• Allergic rash — uncommon, but stop the drug immediately if it occurs
• Drug-induced hepatitis — uncommon but serious; watch for yellow eyes, yellow skin, dark urine

Eperisone — The Least-Sedating Option

What is Eperisone?

Eperisone HCl is an Antispasmodic muscle relaxant with dual mechanism:

1. Muscle relaxation — by reducing nerve signals at the spinal cord
2. Local vasodilation — increases blood flow in spasmed muscles, helping clear inflammatory waste faster

Key Strength

Eperisone causes the least sedation among popular muscle relaxants in Thailand because it primarily acts on the spinal cord, with minimal impact on consciousness centers in the brain.

Dose

50 mg three times daily after meals — standard dosing, may be adjusted per symptoms and patient response.

Brands in Thailand

• Myonal — primary brand from Eisai (Japan), well-established in Thai medical practice
• Epenal, Epera — other available brands

Who Should Use Eperisone?

• Office workers requiring concentration
• Drivers, motorcycle taxi operators
• Elderly patients who fear drowsiness and falls
• Those who have tried Tolperisone but still felt drowsy

Orphenadrine — The Combination Formula

What is Orphenadrine?

Orphenadrine Citrate is an Antispasmodic muscle relaxant with anticholinergic properties (similar to older antihistamines), which is why it causes more drowsiness and dry mouth than other drugs in the class.

Why Combined with Paracetamol?

Orphenadrine relaxes muscles but does not directly relieve pain. Manufacturers combined Paracetamol into a single tablet for simultaneous dual action — Orphenadrine relieves spasm, Paracetamol relieves pain — convenient without needing multiple tablets.

Dose

Orphenadrine 35 mg + Paracetamol 450 mg per tablet, taken 1-2 tablets every 6-8 hours based on severity. Do not exceed 8 tablets per day as Paracetamol would exceed its maximum daily dose.

Brands in Thailand

• Norgesic — primary popular brand
• Norvic, Mygesic — other combination brands

Special Precautions

• Do NOT take additional Paracetamol as it is already included — risk of overdose and liver damage
• Causes more drowsiness than Tolperisone and Eperisone — avoid driving
• Dry mouth, dry throat — due to anticholinergic effect
• Contraindicated in glaucoma or enlarged prostate patients

Chlorzoxazone and Methocarbamol — Other Options

Beyond the 3 popular options, other Antispasmodic muscle relaxants are available in Thailand but less commonly used:

Chlorzoxazone

Acts on the spinal cord, similar to Tolperisone. Often dispensed at pharmacies as a general muscle-relaxer. Dose: 250 mg or 500 mg, 3-4 times daily. Notable side effect: may cause orange or red urine discoloration (harmless but alarming), and may affect the liver with long-term use.

Methocarbamol

More common abroad than in Thailand. Dose: 750 mg-1500 mg, 3-4 times daily. Common side effects: drowsiness, dizziness — an alternative in cases of allergy to Tolperisone or Eperisone.

Antispastics — Baclofen and Tizanidine for Neurological Conditions

The Antispastics group is used differently from Antispasmodics — for chronic muscle spasticity from neurological diseases, not general muscle aches.

Baclofen

Acts on GABA-B receptors in the spinal cord. Used for multiple sclerosis (MS), spinal cord injury, cerebral palsy. Starting dose 5 mg × 3 times/day, gradually titrated up. Do not stop suddenly as it may cause seizures or hallucinations.

Tizanidine

An alpha-2 adrenergic agonist that reduces excitatory signals in the spinal cord. Used for spasticity from stroke, MS, spinal cord injury. Dose 2-4 mg × 3 times/day — may cause low blood pressure, must start low and adjust gradually.

Dantrolene

A Direct-acting agent working on muscle tissue directly. Rarely used, only for malignant hyperthermia (an emergency reaction to anesthetics) or severe spasticity unresponsive to other drugs.

All Antispastics must be prescribed and monitored by a specialist physician — never self-medicate.

Complete Muscle Relaxant Comparison Table

Which Muscle Relaxant Suits Your Symptoms?

Back pain, neck strain, shoulder tension (general symptoms)

→ Tolperisone (Mydocalm or Biocalm) is the first choice — minimal drowsiness, safe, suitable for most people.

Need to work, drive, or focus

→ Eperisone (Myonal) least sedating, does not impact work performance.

Severe pain, need fast relief

→ Norgesic (Orphenadrine + Paracetamol) combined dual-action formula — but causes drowsiness, take before bed or on days off.

Pain with limb numbness (suspected nerve involvement)

→ Soneriper M (Tolperisone + Methylcobalamin) helps with both muscle relaxation and nerve repair.

Chronic neurological conditions

→ Baclofen or Tizanidine, but only when prescribed and monitored by a specialist physician.

Always consult a pharmacist or doctor before deciding, especially for those with chronic conditions, liver/kidney problems, or taking other medications.