Baclofen is a medication that is commonly used to manage spasticity in patients with various neurological conditions, including multiple sclerosis (MS) and spinal cord injuries. It is also prescribed for children and adolescents suffering from cerebral spasticity, particularly those diagnosed with infantile cerebral palsy.

Indications for Baclofen

In adults, Baclofen tablets are approved for treating spasticity linked to conditions such as MS, spinal cord diseases, or injuries, as well as spasticity of cerebral origin. For cases where oral administration is insufficient, Baclofen can be delivered via intrathecal infusion. In pediatric patients, Baclofen is indicated for treating severe chronic spasticity, particularly when oral muscle relaxants have proven ineffective or have caused unacceptable side effects.

Mechanism of Action

Baclofen is a derivative of gamma-aminobutyric acid (GABA), specifically a p-chlorophenyl derivative. Its primary action involves stimulating GABA-B receptors located both presynaptically and postsynaptically. This leads to enhanced presynaptic inhibition primarily within the spinal cord, thereby reducing the transmission of excitatory signals without influencing neuromuscular conduction.

Dosage Guidelines

A gradual titration of Baclofen is recommended to minimize side effects. For adults, treatment typically starts at a daily dose of 15 mg, divided into two to four doses, with gradual increases of 5 to 15 mg as needed, commonly reaching a maximum of 30 to 75 mg per day. For elderly patients or those with specific health concerns, especially renal impairment, a more cautious approach is advised.

In children and adolescents, the initial dose is considerably lower, around 0.3 mg/kg per day, distributed across four doses. The maximum daily dose is capped at 40 mg for younger children and 60 mg for older children. It is recommended that Baclofen be taken with meals along with a sufficient amount of liquid or milk.

Contraindications

Baclofen should not be administered to individuals with epilepsy or other seizure disorders, nor is it suitable for treating spasticity due to rheumatic diseases, Parkinsonism, or peripheral injuries. Terminal renal insufficiency also precludes its use.

Potential Side Effects

Common side effects associated with Baclofen include nausea, vomiting, drowsiness, dizziness, and sedation. These effects may impair the ability to operate vehicles or machinery. While most side effects are transient and diminish with dose adjustment, they can be more pronounced in patients with psychiatric or cerebrovascular conditions, such as those recovering from a stroke. In particular, patients with epilepsy may experience lowered seizure thresholds. Intrathecal administration may introduce infusion-related adverse effects, and men may experience dose-dependent erectile dysfunction.

Drug Interactions

Concurrent use of Baclofen with other muscle relaxants or central nervous system depressants can lead to enhanced effects. Its interaction with alcohol remains unpredictable, and when taken alongside antihypertensive medications, there may be an increased risk of hypotension. Medications affecting renal function may significantly reduce Baclofen excretion, potentially leading to toxic effects.

Use in Pregnancy and Lactation

According to the Embryotox database from the Berlin Charité, Baclofen is not a first-line medication during pregnancy and should be reserved for exceptional cases. During breastfeeding, its use must be carefully evaluated, with preference for alternative treatments, such as physiotherapy or non-steroidal anti-inflammatory drugs like ibuprofen or diclofenac.

Current Guidelines

The recently published S2k guideline for the treatment of spastic syndromes emphasizes that oral muscle relaxants should only be used for spasticity that significantly disrupts daily activities and is not adequately managed by physical therapy or other interventions. In cases of severe disabling spasticity with a potential for secondary complications, intrathecal Baclofen therapy (ITB) is indicated, typically requiring the implantation of a pump for long-term management. Regular monitoring and maintenance of the ITB pump are crucial for patient safety and effective treatment.