Baclofen tablets for treating muscle spasticity in multiple sclerosis

Baclofen is a muscle relaxant used to relieve symptoms of spasticity, especially in patients with multiple sclerosis. It acts on the central nervous system to reduce muscle spasms, clonus, and rigidity, helping improve residual function where spasticity is reversible. Baclofen tablets are available in doses ranging from 5 mg to 20 mg for oral administration.

Baclofen tablets are indicated for alleviating signs and symptoms of spasticity due to multiple sclerosis. They are particularly useful for treating flexor spasms, pain, clonus, and muscle stiffness associated with this condition.

Baclofen may also provide some benefit in patients with spinal cord injuries or other spinal cord diseases, but it is not indicated for spasticity caused by rheumatic disorders, stroke, cerebral palsy, or Parkinson's disease, as efficacy in these conditions has not been established.

Baclofen

Baclofen works by inhibiting nerve reflexes at the spinal cord level, which reduces excessive muscle contractions linked to spasticity. Although structurally related to gamma-aminobutyric acid (GABA), the precise mechanism is not fully understood, and evidence does not conclusively implicate GABA receptor action. The drug depresses the central nervous system, contributing to its muscle relaxant effects and causing sedation and related side effects.

Dosage must be individualized and gradually increased to achieve optimum effect, usually between 40 mg and 80 mg daily. A suggested titration schedule is:

• 5 mg three times daily for 3 days
• 10 mg three times daily for 3 days
• 15 mg three times daily for 3 days
• 20 mg three times daily for 3 days

Further increases can be made if necessary, but the total daily dose should not exceed 80 mg (20 mg four times daily). Use the lowest effective dose, and if no benefit is seen after a reasonable trial, withdraw gradually to avoid withdrawal symptoms.

Known hypersensitivity to baclofen.

Neonatal withdrawal: Infants exposed to baclofen in utero may experience withdrawal symptoms such as increased muscle tone, tremor, jitteriness, and seizures. If baclofen is continued during pregnancy, taper the dose and discontinue before delivery if possible.

Abrupt withdrawal: Sudden discontinuation can cause hallucinations and seizures; taper dosage slowly unless there is a serious adverse event.

Renal impairment: Since baclofen is primarily excreted unchanged by the kidneys, dosage adjustment and caution are required in patients with kidney dysfunction.

Stroke patients: Baclofen has shown limited efficacy and poor tolerability in stroke-related spasticity.

Pregnancy: Animal studies showed risks at high doses; use only if benefits justify potential fetal risks.

Common side effects: Transient drowsiness (10-63%), dizziness (5-15%), weakness (5-15%), and fatigue (2-4%).

Other reported effects:

• Neuropsychiatric: Confusion (1-11%), headache (4-8%), insomnia (2-7%), rarely euphoria, excitement, depression, hallucinations, tremor, ataxia, blurred vision, seizures.
• Cardiovascular: Hypotension (0-9%), rare dyspnea, palpitations, chest pain, syncope.
• Gastrointestinal: Nausea (4-12%), constipation (2-6%), and rarely dry mouth, anorexia, abdominal pain, vomiting, diarrhea.
• Genitourinary: Urinary frequency (2-6%), rarely enuresis, retention, dysuria, impotence, nocturia, hematuria.
• Other: Rash, pruritus, ankle edema, excessive sweating, weight gain, nasal congestion.

Some symptoms may be related to the underlying disease rather than the medication.

Baclofen can increase central nervous system depression when taken with alcohol or other CNS depressants. Caution should be exercised when combining baclofen with these substances.

Pregnancy: Animal studies show potential fetal risks at high doses; no adequate human studies. Use in pregnancy only if benefits justify risks.

Lactation: It is unknown if baclofen is excreted in human breast milk; nursing during treatment is generally not recommended.

Signs of overdose include vomiting, profound muscle weakness, drowsiness, visual accommodation problems, coma, respiratory depression, and seizures.

Treatment involves prompt stomach emptying in alert patients and airway management with endotracheal intubation in obtunded patients. Respiratory support is critical. Do not use respiratory stimulants.

Store tablets at controlled room temperature between 20°C to 25°C (68°F to 77°F). Keep container well closed and out of the reach of children.