Lioresal Intrathekal (Baclofen)

• Baclofen administered intrathecally acts on the central nervous system to reduce spasticity in specific neurological conditions.
• Multiple sclerosis–related spasticity: reduces muscle tone and improves functional mobility.
• Spinal cord injury–related spasticity: decreases involuntary muscle contractions and enhances comfort.
• Refractory central spasticity: provides targeted relief when oral antispastic agents are ineffective.

• Baclofen binds to GABA_B receptors located on presynaptic terminals in the spinal cord, activating an inhibitory G‑protein cascade that reduces calcium influx and suppresses release of excitatory neurotransmitters such as glutamate and aspartate. This inhibition diminishes the activity of spinal reflex arcs, leading to decreased muscle hyperexcitability and spasticity. The effect is dose‑dependent and is enhanced by continuous intrathecal delivery, which achieves higher spinal concentrations while limiting systemic exposure.

Intrathecal baclofen may be associated with a range of adverse reactions, which are categorized by frequency and severity.

Common Side Effects

• Drowsiness
• Nausea or vomiting
• Weakness or reduced muscle strength
• Headache

Serious or Rare Side Effects

• Respiratory depression
• Seizures
• Severe hypotension
• Allergic reactions (rash, angioedema)

• When using intrathecal baclofen, careful clinical monitoring and adherence to safety guidelines are essential.
• Renal impairment: monitor for increased baclofen accumulation and adjust therapy as needed.
• Hepatic impairment: use with caution and observe for enhanced central effects.
• Pregnancy: safety category unknown; avoid use unless benefits outweigh potential risks.
• Concomitant CNS depressants: increased risk of profound sedation and respiratory depression.
• Infection risk: maintain strict aseptic technique during pump implantation and refills.
• Store at 2-8°C: keep refrigerated, protect from light, do not freeze or shake.

Baclofen can interact with several drug classes, requiring attention to avoid additive depressant effects.

Major Interactions (Avoid)

• Opioids: additive central nervous system depression may cause severe respiratory depression.
• Benzodiazepines: combined use can markedly increase sedation and impair coordination.
• Alcohol: concurrent consumption enhances depressant effects and may lead to loss of consciousness.

Moderate Interactions (Monitor Closely)

• Antihypertensive agents: baclofen may potentiate hypotensive effects.
• Anticonvulsants (e.g., phenytoin): may alter baclofen plasma levels.
• Other muscle relaxants: additive reduction in muscle tone may increase weakness.