When should migraine prophylaxis be initiated in adults or adolescents—specifically with ≥4 migraine days per month, ≥2 disabling attacks per month, significant interference with work or daily activities, medication overuse (≥10 days per month of triptans, ergotamines, or combination analgesics), contraindications or intolerance to acute agents, comorbid conditions worsened by migraine, or predictable attack patterns?

Indications for Migraine Prophylaxis

Preventive therapy should be initiated when patients experience ≥2 migraine attacks per month producing disability lasting ≥3 days, use acute medications more than twice weekly (≥10 days/month for triptans or combination analgesics), have contraindications to or failure of acute treatments, or experience uncommon migraine conditions. 1

Primary Indications

Frequency-Based Criteria

• ≥2 migraine attacks per month with disability lasting ≥3 days is the threshold for considering preventive therapy 1, 2
• Patients with less frequent but prolonged, disabling attacks that significantly reduce quality of life between episodes should also receive prophylaxis 2

Medication Overuse

• Acute medication use >2 days per week (approximately 10 days per month) is a strong indication for preventive therapy 1, 2, 3
• This threshold applies to triptans, ergotamines, combination analgesics, and opioids, as exceeding this frequency leads to medication-overuse headache 1, 4

Treatment Response Issues

• Poor response to acute treatment after adequate trials of multiple agents warrants prophylaxis 1, 2
• Contraindications to acute medications (e.g., cardiovascular disease precluding triptans) necessitate preventive therapy 1
• Significant adverse effects from acute therapies that limit their use 5

Specific Clinical Scenarios

• Uncommon migraine subtypes including hemiplegic migraine, basilar migraine, or migraine with prolonged aura 1
• Predictable attack patterns (e.g., menstrual migraine) that allow targeted perimenstrual prophylaxis 6
• Patient preference for prevention over frequent acute treatment 3, 5

Additional Considerations

Quality of Life Impact

• Significant interference with work, school, or daily activities despite optimal acute treatment 1, 5
• Patients who feel their quality of life is substantially reduced between attacks, even if attack frequency is <2 per month 2

Cost and Healthcare Utilization

• Frequent emergency department visits or healthcare encounters for migraine management 3
• High cumulative cost of acute medications 5

Progression Prevention

• Preventive therapy may prevent transformation from episodic to chronic migraine (≥15 headache days per month) 7, 3

Critical Frequency Threshold

The "twice weekly" rule is non-negotiable: any patient requiring acute migraine treatment more than 2 days per week should immediately transition to preventive therapy rather than increasing acute medication frequency, which creates a vicious cycle of medication-overuse headache. 1, 4, 3

Common Pitfalls to Avoid

• Do not wait until patients develop chronic daily headache before initiating prophylaxis—early intervention prevents progression 7, 3
• Do not allow patients to substitute one acute medication for another when overuse is identified; instead, initiate preventive therapy while withdrawing overused agents 4
• Do not dismiss patients with "only" 2-3 attacks per month if those attacks cause severe disability lasting multiple days 1, 2