What is the minimum number of headache days per month required to consider preventative medication for headaches?

Preventative Medication Threshold for Headaches

Consider preventative medication when headaches occur frequently or when acute treatment fails to provide adequate response, though no absolute minimum number of headache days per month is universally mandated for initiating prevention. 1

Clinical Decision Framework

When to Initiate Preventative Therapy

The most recent American College of Physicians guideline (2025) does not specify a rigid threshold of headache days per month, but instead recommends considering preventive medications when:

• Episodic migraine occurs frequently 1
• Acute treatment does not provide adequate response 1

This represents a shift from older, more prescriptive approaches and emphasizes functional impact over arbitrary frequency cutoffs.

Traditional Thresholds Still Referenced

While the 2025 ACP guideline takes a more flexible approach, the International Headache Society criteria (ICHD-3) define specific patterns that warrant attention:

• ≥15 headache days per month for >3 months defines chronic migraine (with migraine features on ≥8 days/month) 1
• Chronic migraine patients should be referred for specialist management and typically require preventive therapy 2

Practical Algorithm for Primary Care

Step 1: Assess headache frequency and impact

• Count total headache days per month using a headache diary 1
• Evaluate disability and quality of life impact 1

Step 2: Optimize acute treatment first

• Ensure patient is using combination therapy (triptan + NSAID or acetaminophen) for moderate-to-severe attacks 1
• Verify acute medications are taken early in the attack 1

Step 3: Consider prevention if:

• Patient continues to have frequent headaches despite optimized acute treatment 1
• Headaches cause significant disability even with effective acute treatment 1
• Patient is approaching or exceeding medication overuse thresholds (≥10 days/month for triptans; ≥15 days/month for NSAIDs) 1
• Patient has ≥15 headache days per month (chronic migraine pattern) 1

Critical Medication Overuse Considerations

Be vigilant about medication overuse headache (MOH) thresholds:

• Triptans, ergots, combination analgesics: ≥10 days per month for ≥3 months 1
• Simple analgesics (NSAIDs, acetaminophen): ≥15 days per month for ≥3 months 1

Patients approaching these thresholds are prime candidates for preventive therapy to reduce the need for acute medications and prevent MOH development 3.

Common Pitfalls to Avoid

Do not wait for an arbitrary number of headache days before considering prevention. The focus should be on functional impairment and treatment response rather than counting days alone 1.

Do not withhold preventive therapy from patients with 8-14 headache days per month if they have significant disability or inadequate response to acute treatment. The 2025 ACP guideline explicitly supports prevention in these scenarios 1.

Recognize that the concept of MOH itself has been questioned in recent literature, with some evidence suggesting that frequent medication use may be a marker of poorly controlled headaches rather than invariably a cause of worsening headaches 4. However, current guidelines still recommend limiting acute medication use to prevent MOH 1, 3.

Evidence-Based Preventive Options

For patients meeting criteria for prevention:

• Topiramate has strong evidence for chronic migraine prevention 5, 3
• OnabotulinumtoxinA is FDA-approved specifically for chronic migraine (≥15 headache days/month) 6, 3, 7
• Other options include beta-blockers, amitriptyline, and valproate (avoid in women of childbearing potential) 6, 8