Side Effects of Baclofen: Monitoring and Management
Baclofen commonly causes drowsiness (10-63%), dizziness (5-15%), weakness (5-15%), and fatigue (2-4%), which can significantly impact quality of life and require careful monitoring. 1
Common Side Effects
- Neuropsychiatric effects: Confusion (1-11%), headache (4-8%), insomnia (2-7%), and less commonly euphoria, excitement, depression, hallucinations, paresthesia, slurred speech, coordination disorders, tremor, ataxia, and visual disturbances 1
- Gastrointestinal effects: Nausea (4-12%), constipation (2-6%), and rarely dry mouth, anorexia, taste disorders, abdominal pain, vomiting, and diarrhea 1
- Cardiovascular effects: Hypotension (0-9%) and rarely dyspnea, palpitations, chest pain, and syncope 1
- Genitourinary effects: Urinary frequency (2-6%) and rarely urinary retention, dysuria, impotence, and hematuria 1
Severe Withdrawal Syndrome
- Abrupt discontinuation of baclofen can lead to potentially life-threatening withdrawal symptoms, especially in patients on long-term therapy 2
- Withdrawal symptoms include visual and auditory hallucinations, anxiety, agitation, delirium, fever, tremors, tachycardia, and seizures 2
- Intrathecal baclofen withdrawal is particularly dangerous and can cause high fever, altered mental status, rebound spasticity, muscle rigidity, rhabdomyolysis, multiorgan failure, and death 2
Special Populations and Considerations
- Elderly patients are at higher risk for adverse effects and typically cannot tolerate doses greater than 30-40 mg per day 3
- Starting dose should be lower in elderly patients (5 mg three times daily) to minimize adverse effects 3
- Renal impairment may increase the risk of toxicity due to reduced drug clearance 4
- Drug interactions: Increased sedation when used with opiates or other CNS depressants 2
Laboratory Abnormalities
- Some patients may experience elevated SGOT, alkaline phosphatase, and blood sugar levels 1
Monitoring Recommendations
- Initial period: Monitor closely for drowsiness, dizziness, and weakness, which are the most common side effects 1, 4
- Long-term therapy: Regular assessment for tolerance development and continued efficacy 4
- Dose adjustments: Consider gradual dose increases to minimize side effects 3
- Discontinuation: Always taper gradually to avoid withdrawal syndrome 2, 5
Management of Side Effects
- Dose reduction may help manage side effects while maintaining therapeutic benefit 4
- Timing adjustments: Administering medication with meals may reduce gastrointestinal side effects 6
- For intrathecal baclofen: Perioperative management should involve specialist input 2
Baclofen can be an effective medication for spasticity and other conditions, but the side effect profile requires careful monitoring and management to optimize patient outcomes and quality of life 4, 7.