When Painkillers Are Causing the Headache

It is one of the more uncomfortable ideas in medicine: the tablets you take for your headache may be the reason you have a headache every day.

Medication overuse headache is common — it affects roughly 1 to 2% of the population — and it is one of the leading causes of chronic daily headache. It is also entirely reversible, which makes recognising it worth the discomfort of the conversation.

How the loop forms

Nobody sets out to overuse painkillers. It happens gradually, and every individual step is sensible.

You get headaches, perhaps migraines. You take something for them, and it works. The headaches become a bit more frequent, so you take something a bit more often. Then you start taking one early, at the first sign, because catching it early works better — which is genuinely good advice for migraine and is where this often begins.

Then you take one preventively, before a meeting or a long drive, because you cannot afford a headache today.

Somewhere in that progression, the brain adapts. Pain-processing pathways become sensitised, and a rebound headache appears as each dose wears off. That headache is treated with another dose. The medication is now maintaining the problem it was taken to solve.

The thresholds

These are specific and worth knowing.

Ten days a month or more for: triptans (sumatriptan and similar), codeine and any opioid, combination painkillers containing codeine or caffeine, and ergotamines.

Fifteen days a month or more for: paracetamol, ibuprofen, aspirin and other simple painkillers used alone.

And the condition is defined by that pattern continuing for more than three months.

The detail that catches most people out: combination painkillers containing codeine are in the lower-threshold group. Co-codamol and similar are among the commonest causes in the UK, and they are available over the counter. Ten days a month is not a lot — two or three a week gets you there without feeling excessive.

What it feels like

• Headache present on most days, often there when you wake up
• A dull, pressing, band-like headache — different in character from your original migraines, although migraines usually continue on top
• Painkillers work less well than they used to, and for less time
• Headache returns as each dose wears off
• Worse in the morning, easing after the first dose of the day
• Poor concentration, irritability, restless sleep
• Increasing anxiety about being without the tablets

The characteristic clue is the medication working less well over time while being needed more often. That combination should always prompt the question.

Why it is easy to miss

People do not count. Ask someone how often they take painkillers and the answer is usually "only when I need to" — which is honest, and not an answer.

Over-the-counter tablets do not feel like medication in the way a prescription does. Nobody thinks of a packet of paracetamol as a drug with a monthly limit.

And doses are spread across sources: some from the pharmacy, some prescribed, a few from a drawer at work. No single record shows the total.

What to do

1. Count, honestly, for four weeks

Every dose, from every source, including anything you took "just in case". Most people are surprised by the number, and the number is the diagnosis.

2. Get it assessed before you change anything

Not everything is medication overuse headache. It is worth excluding other causes, and there are headaches that need urgent assessment — see below. A consultation should also cover whether you have an untreated primary headache disorder underneath, because you almost certainly do.

3. Stop the overused medication

This is the treatment, and there is no gentler alternative.

For simple painkillers and triptans, stopping abruptly is generally recommended and is the fastest route through.

For codeine and opioids, do not stop abruptly. These need a supervised taper, and this is where medical support genuinely matters rather than being a formality.

4. Expect it to get worse first

This is the part people are not warned about, and it is why most attempts fail.

Headaches typically worsen for one to two weeks after stopping, sometimes with nausea, poor sleep, restlessness and irritability. Then they improve. Most people see substantial improvement by four to eight weeks, and full benefit can take up to twelve.

Knowing the bad fortnight is coming, and that it is a sign of the process working rather than of failure, is the single biggest predictor of getting through it.

5. Have preventive treatment in place

Withdrawal is far easier with a preventer already started — propranolol, amitriptyline, topiramate or candesartan, depending on your circumstances. Anti-sickness medication helps the first fortnight considerably.

This is why doing it with medical support is worth it. Not because the stopping is complicated, but because the fortnight is much more survivable with the right things in hand.

Afterwards

Once through, the underlying headache disorder is usually far more treatable — and often much less frequent than it appeared. People are frequently startled to find their "daily headache" was two migraines a month wearing a disguise.

The rule going forward: acute headache medication on no more than two days a week. If you need more, you need a preventer, not more painkillers.

Keep a headache diary. Free apps do this well, and it makes any future review far more useful.

When a headache needs urgent assessment

Go to A&E or call 999 for:

• A sudden, severe headache reaching maximum intensity within seconds — a thunderclap headache
• Headache with fever, neck stiffness, or a rash that does not fade under a glass
• Headache with weakness, numbness, confusion, slurred speech or visual loss
• Headache after a head injury
• Headache with a seizure

Seek prompt assessment for: a headache that is markedly different from your usual pattern; one that is worse lying down, on coughing or straining; a new headache over the age of 50, particularly with scalp tenderness or jaw pain on chewing; or a new headache in pregnancy.

If the count over four weeks looks higher than you expected, a consultation can confirm what is happening, get a preventer started, and plan the withdrawal properly.