Baclofen

Baclofen is a muscle relaxant that works on the brain and spinal cord to relieve muscle stiffness or spasm while maintaining muscle strength. It inhibits both monosynaptic and polysynaptic reflexes at the spinal level by stimulating GABA-B receptors, which inhibits the release of glutamate and aspartate. It also acts at intraspinal sites producing CNS depression and exerts an antinociceptive effect.

Common side effects include transient drowsiness, daytime sedation, dizziness, weakness, and fatigue.

• Spasticity resulting from multiple sclerosis
• Flexor spasms and concomitant pain, clonus and muscular rigidity
• Skeletal muscle spasm resulting from rheumatic disorders
• Spinal cord injuries and other spinal cord diseases
• Cerebrovascular accidents or neoplastic or degenerative brain disease

Baclofen stimulates GABA-B receptors at the spinal level, inhibiting both monosynaptic and polysynaptic reflexes, which reduces the release of glutamate and aspartate and decreases excessive muscle contraction. It also acts at intraspinal sites producing CNS depression and exerts an antinociceptive effect.

Baclofen acts as a GABA-B receptor agonist in the spinal cord, enhancing inhibitory neurotransmission and reducing the release of excitatory neurotransmitters (glutamate and aspartate). This reduces motor neuron hyperexcitability and relaxes muscles. It acts directly on the brain and spinal cord to control muscle stiffness and spasms.

Adults and children over 10 years:

• Initial dose: 5 mg 3 times daily (with or after food), gradually increased
• Dose titration: 5 mg tid for 3 days → 10 mg tid for 3 days → 20 mg tid or until desired effect
• Maximum dose: 100 mg daily

Children under 10 years:

• Initial dose: 2.5 mg (2.5 ml) 4 times daily, gradually increased
• Maintenance dose:
  • 12 months-2 years: 10-20 mg/day
  • 2-6 years: 20-30 mg/day
  • 6-10 years: 30-60 mg/day
• Maximum: >10 years: 2.5 mg/kg/day

Elderly: Initiate with lower doses.

Renal impairment: Dose reduction may be required (approximately 5 mg/day).

Take with or after food. Swallow the tablet whole; do not chew or crush. Take regularly as advised by your doctor.

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and continue with your regular schedule. Do not double the dose.

• Transient drowsiness
• Daytime sedation
• Dizziness
• Weakness and fatigue
• Headache (<10%)
• Insomnia (<10%)
• Nausea (~10%)
• Constipation (<10%)
• Hypotension (<10%)
• Urinary frequency (<10%)

Rare: Euphoria, excitement, depression, confusion, hallucinations, paraesthesia, nightmares, muscle pain, tinnitus, blurred vision, epileptic seizures, respiratory depression, erectile dysfunction, rash, pruritus, weight gain, etc.

• Caution when driving or operating machinery (may cause drowsiness and dizziness)
• Avoid alcohol consumption
• Do not stop suddenly after long-term use
• Use lower doses in renal impairment (approximately 5 mg/day)
• Caution and close monitoring in patients with psychotic disorders, schizophrenia, depression, or manic disorders
• May lower seizure threshold in epilepsy patients
• Caution in patients with peptic ulcer, cerebrovascular disease, hepatic, renal, or respiratory failure
• Caution during pregnancy and lactation

• Hypersensitivity to baclofen or any component
• Active peptic ulcer disease

• Antihypertensives: May increase hypotensive effects
• Levodopa (in Parkinson's patients): May cause confusion, agitation, hallucinations
• CNS depressants and alcohol: May potentiate CNS effects (potentially fatal)
• Tricyclic antidepressants: May potentiate muscular hypotonia
• MAO inhibitors: May increase CNS depressant effects
• Magnesium sulfate and other neuromuscular blockers: Synergistic effect may occur

[UNSAFE] Alcohol with Baclofen may cause excessive drowsiness. Avoid alcohol.

[CONSULT YOUR DOCTOR] Safety during pregnancy has not been established (Category B3). Baclofen crosses the placental barrier. Use only if clearly needed and under medical supervision.

[SAFE IF PRESCRIBED] Baclofen is excreted in breast milk in very small amounts. Evidence suggests quantities are so small that no undesirable effects on the infant would be expected.

Children under 10 years: 2.5 mg (2.5 ml) 4 times daily initially, gradually increased. Maintenance: 12 months-2 years: 10-20 mg/day; 2-6 years: 20-30 mg/day; 6-10 years: 30-60 mg/day.

Children over 10 years: Same as adult dose.

Elderly patients should start with lower doses.

[CAUTION] Dose reduction required in renal impairment (approximately 5 mg/day). Caution in chronic hemodialysis patients.

[CAUTION] Caution in hepatic impairment. Regular laboratory tests should be performed in patients with hepatic disease.

Symptoms: Severe overdose requires gastric lavage. Respiratory depression, seizures, coma may occur.

Management: Gastric lavage, symptomatic and supportive treatment.

Store below 30°C, away from light and moisture. Keep out of reach of children.

Baclofen (C₁₀H₁₂ClNO₂)