Methocarbamol (Ortoton®)

Methocarbamol is a centrally acting muscle relaxant used to treat painful muscle tension. A brand-name product containing this active ingredient is Ortoton®. Methocarbamol is frequently used for acute back pain with muscle hardening.

The active ingredient relaxes the skeletal muscles without severely impairing voluntary motor function. It acts via the central nervous system and reduces pathologically increased muscle tension.

Methocarbamol is usually used as a concomitant medication together with pain relievers and physical therapy.

Methocarbamol has a central muscle-relaxing effect:

Mechanism of action:

• Inhibits polysynaptic reflexes in the spinal cord and brainstem
• Reduces pathologically increased muscle tone
• Breaks the vicious cycle of pain – tension – pain

Special feature:

• Acts primarily on excessive muscle tension
• Normal muscle strength is largely preserved
• Less sedation than other muscle relaxants

Pharmacokinetics:

• Onset of action: approx. 30 minutes
• Half-life: 1–2 hours
• Metabolized in the liver

Methocarbamol is suitable for:

• Acute painful muscle tension
• Back pain with a muscular component
• Neck and shoulder tension
• Lumbago (acute low back pain)
• Muscle cramps after injuries

Recommended as:

• Adjunctive therapy to analgesics
• A supplement to physical therapy
• Short-term treatment (max. 2–3 weeks)

Not suitable:

• In myasthenia gravis
• In epilepsy
• For children and adolescents

Tablets:

• 750 mg

Usual dosage (adults):

• Initial dose: 3 × 2 tablets (4500 mg/day) for 2–3 days
• Maintenance dose: 3 × 1 tablet (2250 mg/day)

Duration of treatment:

• Usually 2–3 weeks
• Not intended for long-term use

Note: The initial dose is deliberately high in order to break the tension cycle quickly.

How to take:

• Swallow the tablets whole with sufficient water
• With or without food
• 3 times daily at regular intervals

Important notes:

• Your ability to drive may be impaired
• No alcohol during treatment (increased sedation)
• May turn the urine dark (harmless)
• Do not drive if you experience dizziness or fatigue

Methocarbamol must not be taken in cases of:

• Hypersensitivity to methocarbamol
• Myasthenia gravis
• Comatose or precomatose states
• Diseases of the central nervous system
• A tendency to epileptic seizures

Caution in:

• Hepatic insufficiency
• Impaired renal function
• Elderly patients (risk of falls)

Pregnancy/breastfeeding: Not recommended due to insufficient data.

Rare (0.01 to 0.1%):

• Headache, dizziness, metallic taste
• Low blood pressure (hypotension)
• Inflammation of the conjunctiva (conjunctivitis)
• Swelling of the nasal mucosa
• Skin reactions (angioedema, rash, itching, hives)
• Fever

Very rare (less than 0.01%):

• Anaphylactic reactions
• Decreased appetite
• Restlessness, anxiety, confusion
• Fainting (syncope), involuntary eye movements (nystagmus), light-headedness, trembling (tremor), seizures
• Deterioration of vision, double vision
• Bradycardia (slowed heartbeat)
• Hot flushes
• Retching, vomiting

Frequency not known:

• Drowsiness (somnolence), fatigue
• Coordination disorders
• Temporary sensory disturbances (hypoaesthesia, paraesthesia), mainly on the head, mouth, hands or feet
• Nausea, diarrhoea

Urine discoloration: May turn the urine brown, black, or greenish – this is harmless.

Increased sedation with:

• Alcohol
• Benzodiazepines
• Opioids
• Antihistamines
• Tricyclic antidepressants

Other:

• Pyridostigmine: effect may be weakened (myasthenia gravis)
• Centrally acting medications in general: mutual potentiation of effects

Note: Methocarbamol has relatively few clinically relevant interactions compared with other muscle relaxants.