When is migraine prophylaxis indicated?

Indications for Migraine Prophylaxis

Migraine prophylaxis is indicated when patients experience ≥2 migraine attacks per month producing disability lasting ≥3 days, when acute medication is used more than twice per week, when acute treatments fail or are contraindicated, or when uncommon migraine conditions are present. 1

Primary Indications

The decision to initiate preventive therapy is based on four core criteria that reflect both attack frequency and functional impact:

• Attack frequency and disability: Prophylaxis is recommended for patients with two or more attacks per month that produce disability lasting three or more days, as this threshold indicates significant functional impairment. 1

• Medication overuse threshold: Use of abortive medication more than twice per week (approximately 10 days per month) is a strong indication for preventive therapy, as this pattern creates risk for medication-overuse headache and can convert episodic migraine into chronic daily headache. 1, 2

• Failure of acute treatment: Prophylaxis should be considered when acute treatments are contraindicated, produce severe side effects, or fail to provide adequate relief after appropriate trials. 1, 3

• Uncommon migraine subtypes: Patients with hemiplegic migraine, basilar migraine, or prolonged aura warrant preventive therapy regardless of attack frequency due to the severity and potential complications of these variants. 1

Secondary Considerations

Beyond the primary indications, several additional factors support the decision to initiate prophylaxis:

• Attack severity and duration: Less frequent attacks (fewer than two per month) may still warrant prophylaxis if they are prolonged, severely disabling, or significantly reduce quality of life between attacks. 3, 4

• Patient preference and quality of life: Strong patient preference for prevention over repeated acute treatment is a valid indication, particularly when patients perceive that their quality of life is reduced between attacks. 1, 3

• Cost considerations: The cumulative cost of frequent acute medication use may exceed the cost of daily preventive therapy, making prophylaxis economically justified. 1

• Prevention of chronification: Early initiation of preventive therapy may prevent progression from episodic migraine to chronic migraine (≥15 headache days per month), though this benefit requires further validation. 5

Practical Implementation Algorithm

When evaluating a patient for prophylaxis, follow this structured approach:

1. Quantify attack frequency: Have the patient maintain a headache diary for at least one month to accurately document migraine days, as patients often under-report milder attacks. 1, 2

2. Assess acute medication frequency: Calculate total days per month of acute medication use across all drug classes (NSAIDs, triptans, combination analgesics). If ≥10 days per month for triptans or ≥15 days per month for NSAIDs, prophylaxis is mandatory. 1, 2

3. Evaluate disability: Use validated tools or simply ask: "How many days per month are you unable to perform your usual activities due to migraine?" If ≥3 days, prophylaxis is indicated. 1

4. Screen for contraindications to acute therapy: Document cardiovascular disease, uncontrolled hypertension, or other conditions that limit acute treatment options. 1

5. Discuss patient goals: Explicitly ask whether the patient desires fewer attacks, even if it requires daily medication. Patient willingness to accept prophylaxis significantly impacts adherence. 4

Common Pitfalls to Avoid

• Delaying prophylaxis while trialing multiple acute strategies: This approach allows medication overuse to develop and permits chronification. Once the threshold of twice-weekly acute medication use is reached, initiate preventive therapy immediately. 1, 2

• Waiting for "enough" attacks: The guideline threshold of two attacks per month is a minimum, not a target. Patients with one severely disabling attack per month may benefit from prophylaxis if quality of life is impaired. 3, 4

• Ignoring subclinical medication overuse: Patients using acute medication 8–9 days per month are approaching the overuse threshold and should be counseled about prophylaxis before the pattern becomes entrenched. 1, 2

• Failing to address modifiable triggers: Before or concurrent with pharmacological prophylaxis, systematically identify and mitigate triggers such as sleep deprivation, stress, caffeine overuse, and alcohol consumption. 1

Divergent Evidence and Nuances

The 2025 American College of Physicians guideline 1 and older research literature 3, 6, 5, 7, 4 converge on the core indications, with minor variations in emphasis. The twice-weekly acute medication threshold is consistently cited across all sources as a critical trigger for prophylaxis. The 2000 French guideline 3 emphasizes quality-of-life impairment between attacks as an indication, which is less prominent in the 2025 guideline but remains clinically relevant. The 2008 European perspective 6 notes that prophylaxis may prevent progression to chronic migraine, though this claim is presented as theoretical rather than evidence-based.