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), it 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overuse of acute treatment for more than 3 months, and which characteristically improves once the overused drug is withdrawn.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”). It is the commonest cause of chronic daily headache seen in primary care, yet it is repeatedly missed – largely because patients do not volunteer the over-the-counter (OTC) and codeine-containing analgesics they rely on.

The key skills are to recognise the pattern, take a meticulous 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 / month	Sumatriptan; codeine / co-codamol; Migraleve; ergotamine
Paracetamol, aspirin, or an NSAID (alone or in any combination)	≥ 15 days / 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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