Medication-Overuse Headache: Causes and How to Break the Cycle

What Is a Medication-Overuse Headache?

Medication-overuse headache (MOH), often called a rebound headache, is a long-lasting headache caused by the regular, frequent use of medicines meant to treat headache pain. It is a recognised headache disorder in its own right, not simply a side effect. It develops in people who already get headaches — usually migraine or tension-type headache — and who, understandably, treat them with pain relief. Over time, the treatment itself becomes part of the problem.

The tell-tale pattern is an occasional headache that has quietly turned into an almost-daily one. People often find they are waking with a headache, that their usual painkiller works less well than it used to, and that the pain returns as each dose wears off. It is one of the more common reasons a manageable headache becomes a chronic, everyday burden.

The Vicious Cycle Explained

MOH is a self-reinforcing loop. The frustrating part is that every step in it feels completely reasonable at the time:

• radio_button_uncheckedYou get a headache and take a painkiller — sensible, and it helps.
• radio_button_uncheckedAs the dose wears off, the headache returns, sometimes worse than before.
• radio_button_uncheckedYou take another dose to settle it, which again works for a while.
• radio_button_uncheckedYour body adapts to the frequent medicine, so headaches become more frequent and the relief shorter.
• radio_button_uncheckedYou end up taking pain relief on most days, yet feel worse rather than better.

The result is a headache that is present on most days, does not fully clear, and no longer responds well to the medicine driving it. Breaking the loop feels counter-intuitive because the one thing that seems to help — taking more painkillers — is exactly what keeps it going.

Which Medicines Cause It — and How Often

Almost any acute headache or pain medicine can cause MOH if used too often, but they are not equal. Opioids — including codeine combinations — carry the highest risk and can trigger MOH at lower frequencies. Triptans (migraine-specific medicines) and combination products that include caffeine come next. Simple single-ingredient painkillers such as paracetamol, ibuprofen and aspirin are the least likely to cause it, though they still can with frequent use.

The Australian Codeine Story

Codeine deserves its own mention because of a major Australian regulatory change. Since 1 February 2018, all medicines containing codeine — including low-dose combination painkillers such as codeine-with-paracetamol and codeine-with-ibuprofen — have been prescription-only in Australia. Before that date, these products could be bought over the counter at pharmacies, and they were among the most common drivers of medication-overuse headache.

The Therapeutic Goods Administration (TGA) made the change (known as up-scheduling) largely because of the harms linked to easy, repeated access — including dependence, and the way frequent codeine use can worsen headaches rather than relieve them. If you still have older over-the-counter codeine products at home, or you have been getting repeat scripts to manage frequent headaches, this is worth raising with your GP, as codeine is one of the harder overused medicines to stop safely.

How to Recognise a Rebound Headache

MOH can be easy to miss because it hides behind the headache you already had. The clues are in the pattern of your headaches and your medicine use rather than the type of pain itself:

• radio_button_uncheckedHeadaches on 15 or more days a month, often present when you wake.
• radio_button_uncheckedYou have been using headache or pain medicine regularly for three months or more.
• radio_button_uncheckedHeadaches have gradually become more frequent over weeks or months.
• radio_button_uncheckedThe pain returns or worsens as each dose wears off.
• radio_button_uncheckedYour usual painkiller works less and less well over time.
• radio_button_uncheckedThe headache is often dull and persistent (tension-like) but can have migraine-like features on some days.

How to Break the Cycle

The good news is that MOH is reversible. The bad news is that there is no way around the central step: the overused medicine has to be reduced or stopped. This is called withdrawal, and while it is uncomfortable for a short period, most people improve substantially within weeks. Doing it with your GP's guidance makes it safer and much more likely to succeed.

What to expect during withdrawal

Be prepared for things to feel worse before they feel better. As the overused medicine leaves your routine, headaches often intensify for a period — commonly one to two weeks — and some people also feel nauseous, restless or have trouble sleeping. This is a normal, temporary part of resetting, not a sign the plan is failing. Your GP may offer a short bridging treatment to make this stretch more bearable, and can advise on which non-overused options are safe to use sparingly in the meantime. After the withdrawal period, most people find their headaches settle back to their previous, less frequent pattern.

How to Prevent It Happening Again

• radio_button_uncheckedTrack your medicine days. Keep a simple headache diary or note pain-relief days on your phone calendar — MOH creeps up precisely because the days are easy to lose count of.
• radio_button_uncheckedTreat early, but not constantly. Taking a painkiller promptly for a genuine headache is fine; taking one pre-emptively 'just in case' most days is how the cycle starts.
• radio_button_uncheckedFavour single-ingredient painkillers over combinations for frequent headaches, and be especially cautious with anything containing codeine or caffeine.
• radio_button_uncheckedAddress the underlying headache. If migraine or tension headaches are driving frequent medicine use, a GP prevention plan tackles the root cause.
• radio_button_uncheckedSee your GP early if headache days are climbing. It is far easier to prevent MOH than to unwind it once established.

When to See Your GP

Frequent headaches are always worth a conversation with your GP, and MOH specifically needs medical guidance to treat well. Make an appointment if any of the following apply to you:

• radio_button_uncheckedYou are taking headache or pain medicine on more than 2 to 3 days a week on a regular basis.
• radio_button_uncheckedYour headaches are on 15 or more days a month, or have been steadily increasing.
• radio_button_uncheckedYour usual painkiller is working less well than it used to.
• radio_button_uncheckedYou have been using codeine-containing or other opioid products regularly and want to cut back.
• radio_button_uncheckedYou want to stop an overused medicine but are worried about the withdrawal period.

Frequently Asked Questions

Can painkillers really cause headaches?

Yes. Taken too often, the medicines used to treat headaches can start causing them — a recognised condition called medication-overuse or rebound headache. It develops in people who already get headaches and treat them frequently with pain relief. The medicine helps in the short term, but with regular use the headaches become more frequent and the relief shorter, creating a cycle. Cutting back the overused medicine reverses it.

How many days a month is too many for painkillers?

For simple painkillers on their own (paracetamol, ibuprofen or aspirin), the risk of rebound headache rises at 15 or more days a month. For stronger or combination products — codeine and other opioids, triptans, and caffeine combinations — the threshold is lower, at 10 or more days a month. As a practical prevention rule, keep acute pain-relief use to no more than 2 to 3 days a week. If you need it more often, see your GP.

Which painkillers are most likely to cause rebound headaches?

Opioids, including codeine combinations, carry the highest risk and can trigger rebound headache at lower frequencies. Triptans and combination products containing caffeine come next. Plain single-ingredient painkillers — paracetamol, ibuprofen and aspirin — are the least likely to cause it, though they still can with frequent use. This is one reason single-ingredient products are generally preferred over combinations for people prone to frequent headaches.

Why can't I still buy codeine painkillers over the counter in Australia?

Since 1 February 2018, all codeine-containing medicines have been prescription-only in Australia. The TGA up-scheduled them because of harms linked to easy repeated access, including dependence and the worsening of headaches with frequent use. Low-dose codeine combination painkillers were previously available over the counter and were a common cause of medication-overuse headache. If you relied on these products, talk to your GP about safer options.

How do I stop rebound headaches?

The only effective treatment is to reduce or stop the overused medicine, ideally with your GP's guidance. Simple painkillers and triptans can often be stopped outright, while codeine and other opioids should be reduced gradually rather than stopped suddenly. Expect headaches to worsen for one to two weeks during withdrawal before improving. Your GP may offer a short bridging treatment to ease this period and may start a preventive medicine to reduce future headaches.

How long does it take to recover from medication-overuse headache?

Most people notice a clear improvement within a few weeks of cutting back the overused medicine, though the first one to two weeks are usually the hardest as withdrawal headaches peak. Full recovery — with headaches returning to their previous, less frequent pattern — can take a couple of months. Because relapse is common, prevention habits like keeping pain-relief days to 2 to 3 a week matter just as much after recovery as before.

Is medication-overuse headache permanent?

No — it is reversible. Once the overused medicine is reduced or stopped and the withdrawal period passes, the headaches typically settle back to how they were before. The key is not to slip back into frequent use, which is why an underlying headache condition such as migraine is often worth treating with a prevention plan so you do not need acute pain relief as often.