What is the recommended dosage and usage of Flunarezine (flunarizine) for migraine prophylaxis in an adult patient with no significant medical history?

Flunarizine for Migraine Prophylaxis

Recommended Dosage and Positioning

Flunarizine 5-10 mg orally once daily is an effective second-line agent for migraine prophylaxis in adults, with proven efficacy comparable to propranolol and topiramate. 1

The standard dosing is:

• 10 mg once daily (typically at night) is the most commonly used and studied dose 1, 2
• 5 mg once daily is an alternative for patients concerned about side effects, particularly weight gain or sedation 1
• Lower doses (3 mg daily) show similar efficacy with reduced side effects, though 10 mg remains standard 3

Clinical Positioning in Treatment Algorithm

Flunarizine is classified as a second-line preventive medication for migraine prophylaxis 1, 4:

First-line agents to consider before flunarizine:

• Propranolol (80-240 mg/day) or timolol (20-30 mg/day) 1, 4
• Topiramate (50-100 mg/day) 1, 4
• Candesartan (for patients with comorbid hypertension) 4

When to use flunarizine:

• After failure or intolerance of first-line beta-blockers or topiramate 1, 4
• In patients where first-line agents are contraindicated 1
• Particularly effective in chronic migraine, migraine with aura, and hemiplegic migraine 2

Evidence for Efficacy

Flunarizine has proven efficacy supported by multiple placebo-controlled trials 1:

• Reduces migraine attack frequency by approximately 50% after 16 weeks of treatment 5
• Decreases headache indices by up to 82% in classical migraine 6
• Effective in 76% of patients (24% report no clinical effect) 2
• Benefits may take 4 months to fully manifest in some patients 6

Implementation Strategy

Initiation and titration:

• Start with 5-10 mg once daily, taken at night to minimize daytime sedation 1, 2
• Allow an adequate trial period of 2-3 months before assessing efficacy, though some patients may require up to 4 months 1, 6
• Most patients who respond continue treatment for more than 1 year (64% in UK cohort) 2

Monitoring:

• Track attack frequency, severity, and disability using headache diaries 1, 4
• Assess for side effects at follow-up visits within 2-3 months 1
• After 6-12 months of stability, consider tapering or discontinuing treatment 1, 4

Adverse Effects and Contraindications

Common adverse effects (generally well-tolerated):

• Sedation and daytime tiredness (most common) 1, 2
• Weight gain 1, 2
• Abdominal pain 1

Serious adverse effects (particularly in elderly):

• Depression 1
• Extrapyramidal symptoms 1

Absolute contraindications:

• Active Parkinsonism or history of extrapyramidal disorders 1
• Current depression (relative contraindication, use with caution) 1

Practical consideration: Only 10.5% of patients discontinue flunarizine due to adverse effects, indicating good overall tolerability 2

Critical Pitfalls to Avoid

Before initiating flunarizine:

• Rule out medication overuse headache (≥10 days/month of triptan use or ≥15 days/month of NSAID use) 4
• Screen for depression and Parkinson's disease, as flunarizine may exacerbate these conditions 1
• Avoid in elderly patients due to increased risk of extrapyramidal symptoms and depression 1

During treatment:

• Do not judge efficacy before 2-3 months (minimum), and allow up to 4 months in some cases 1, 6
• Monitor for weight gain and mood changes at each follow-up 2
• Limit acute medication use to prevent interference with preventive therapy 1

Availability Considerations

Flunarizine is not licensed in the United States but is widely used in Europe and other countries where it is available 1, 2. In the UK, the National Institute for Clinical Excellence published supportive guidelines for its use in 2014 based on randomized controlled evidence 2.