Medication Overuse Headache (MOH)

🔍 When to Suspect

Chronic daily or near-daily headache (present on ≥15 days/month) that has developed or worsened while taking regular painkillers for a pre-existing headache disorder

From the full topic in The Ocean Library: Medication Overuse Headache (MOH)

🧭 When to suspect

Medication overuse headache (MOH) is a secondary headache that develops in someone with a pre-existing primary headache – usually migraine or tension-type headache (TTH) – who has been using acute or symptomatic headache medication too frequently.

Under the International Classification of Headache Disorders, 3rd edition (ICHD-3), MOH is a headache:

• present on ≥ 15 days per month

• that has developed or worsened during regular overuse of acute treatment for more than 3 months

• that characteristically improves once the overused drug is withdrawn.

The mechanism is a vicious cycle: the acute drug, taken too often, perpetuates and amplifies the very headache it was meant to relieve (“rebound”).

• MOH is the commonest cause of chronic daily headache seen in primary care.

• MOH is repeatedly missed – largely because patients do not volunteer the over-the-counter (OTC) and codeine-containing analgesics they rely on.

Recognise the pattern, take a detailed medication history, exclude a secondary cause (red flags), and treat by withdrawal – not by escalating analgesia. The overuse threshold differs by drug class.

Acute medication class	Overuse threshold (for > 3 months)	Typical UK examples
Triptans, opioids, ergots, or combination analgesics	≥ 10 days per month	• Sumatriptan • Codeine/co-codamol • Migraleve • Ergotamine
Paracetamol, aspirin, or an NSAID (alone or in any combination)	≥ 15 days per month	• Paracetamol • Ibuprofen (Nurofen), naproxen • Aspirin

Risk is higher with a background of frequent migraine or TTH, comorbid anxiety or depression, and high caffeine intake (including caffeine-containing analgesics). Suspect MOH in any patient reporting near-daily headache who is using acute treatment on more days than not.

Source: NICE CG150 · ICHD-3

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