What are the side effects of Flunarizine?

Flunarizine Side Effects

Flunarizine commonly causes sedation, weight gain, depression, and extrapyramidal symptoms, particularly in elderly patients. 1, 2

Common Side Effects

Central Nervous System Effects

• Sedation/drowsiness: Occurs in up to 42% of patients, especially within the first month of treatment 3
• Depression: Can manifest as a retarded type depression, reported as the most frequent cause of treatment discontinuation (7.5% of patients) 3
• Extrapyramidal symptoms: Particularly in elderly patients, including:
  • Parkinsonism
  • Dystonia
  • Dyskinesia
  • Akathisia 2

Metabolic Effects

• Weight gain: Occurs in approximately 54% of patients
  • Average weight gain of 7.9 ± 6.9 kg 3
  • One of the most common reasons for discontinuation 4

Other Common Side Effects

• Abdominal pain 1
• Mood changes 5
• Fatigue/tiredness 5

Serious Side Effects

Neurological Complications

• Depression: Can be severe enough to require discontinuation of treatment 4
• Extrapyramidal symptoms: May persist despite treatment discontinuation 2
• Tardive dyskinesia: Characterized by involuntary movements of the face, tongue, and extremities 2
• Neuroleptic malignant syndrome: Rare but potentially fatal complication with symptoms including:
  • Hyperthermia
  • Muscle rigidity
  • Altered mental status
  • Autonomic instability 2

Cardiovascular Effects

• Hypotension (rare) 2
• Blood pressure fluctuations 2

Risk Factors for Side Effects

• Age: Elderly patients are more susceptible to extrapyramidal symptoms and depression 1, 2
• Dose: Side effects are dose-dependent, with higher incidence at 10 mg compared to 5 mg 6
• Duration of treatment: Long-term use increases risk of certain side effects like weight gain 3
• Pre-existing conditions: Patients with history of depression or movement disorders may be at higher risk 2

Monitoring Recommendations

• Regular assessment of:
  • Weight changes
  • Mood and signs of depression
  • Movement disorders/extrapyramidal symptoms
  • Sleep patterns 3

Clinical Considerations

• Side effects often appear within the first month of treatment 3
• Depression is more common with flunarizine (8%) compared to other migraine preventives like metoprolol (3%) 4
• The risk of side effects must be balanced against the efficacy in migraine prevention, where flunarizine has shown to reduce migraine days by approximately 37% 4
• To minimize side effects, consider:
  • Starting with lower doses (5 mg)
  • Administering at bedtime to reduce daytime sedation
  • Using special administration schedules 7, 6

Despite its efficacy in migraine prevention, flunarizine's side effect profile, particularly weight gain, sedation, and depression, often limits its long-term use and should be carefully considered when selecting treatment options for patients.