Medication Overuse Headache (MOH): When the Painkiller Becomes the Cause

MOH is a recognised and well-established neurological diagnosis in the International Classification of Headache Disorders (ICHD-3) — the same classification system used globally for all headache disorders. It has a clear biological mechanism: chronic exposure to acute analgesics and triptans changes how the brain's pain-modulating systems work, leading to sensitisation and increased headache frequency. The recommendation to reduce medication use is not about judging how many tablets you take. It is a clinical necessity — without it, no other treatment will work. The good news is that withdrawal and preventive therapy produce substantial improvement in most patients.

The withdrawal period — during which headache often temporarily worsens before improving — typically lasts 7 to 14 days. After that, headache frequency begins to fall. By 4 to 6 weeks after withdrawal, most patients notice a significant reduction in headache days. By 3 months, the preventive medication initiated alongside withdrawal has usually reached its therapeutic effect. Full benefit is typically apparent at 3 to 6 months. Some patients improve dramatically within 2 weeks of stopping the overused drug. Progress is tracked at every follow-up with the headache diary.

Preventive medications work by modulating the central pain pathways that make migraine brains more susceptible to attacks. Medication overuse causes these same pathways to become sensitised and downregulated — directly counteracting what the preventive is trying to achieve. The neurobiological environment created by chronic overuse is incompatible with preventive efficacy. This is not theoretical: clinical trials have consistently shown that preventive medications added to active MOH produce little or no benefit, while the same preventives after withdrawal produce significant benefit. Stopping the overused medication is not optional if you want the preventive to work.

Withdrawal headache is a temporary worsening of headache in the days immediately after stopping the overused medication. It typically begins within 12 to 24 hours of the last dose, reaches peak severity on days 2 to 5, and gradually improves by days 7 to 14. Accompanying symptoms may include nausea, vomiting, sleep disturbance, restlessness, and anxiety. This is managed with bridge therapy — typically naproxen 500mg twice daily, with antiemetics for nausea, and a short course of prednisolone in more severe cases. It is important to be prepared for this period before starting withdrawal; patients who are not warned often give up and return to the overused medication, restarting the cycle.

Not forever. After successful withdrawal and establishment of effective preventive therapy, most patients can use appropriate acute medications — triptans, NSAIDs, or paracetamol — for breakthrough attacks, as long as they stay within the relevant limits (no more than 8–10 days per month for triptans and opioids; no more than 15 days per month for simple analgesics). The goal is not permanent abstinence. The goal is keeping medication use below the thresholds that cause MOH. Understanding these thresholds and counting medication days each month is the key to staying headache-free long-term.

Yes. CGRP monoclonal antibodies — erenumab (Aimovig), fremanezumab (Ajovy), and galcanezumab (Emgality) — have been specifically studied in MOH patients. The FOCUS trial (fremanezumab) and similar studies demonstrated that CGRP antibodies reduce headache frequency and medication use days in MOH patients, with effects seen even without complete prior withdrawal. This is clinically significant for patients who have found withdrawal difficult: CGRP mAbs offer a pathway to reduced medication use without requiring complete prior detoxification as a prerequisite. They are available at KIMS and eligibility is assessed at the headache clinic.

Tramadol is an opioid, and opioid overuse carries the highest MOH risk of any medication class. Tramadol causes MOH at lower frequency of use than simple analgesics or triptans, and opioid withdrawal is more severe (and can be medically dangerous if abrupt discontinuation is attempted without supervision). If you are taking tramadol for headache more than a few days per month, you should discuss this urgently with a specialist. Withdrawal from tramadol should be gradual and supervised, not abrupt. KIMS offers inpatient supervised withdrawal for opioid overuse headache.

MOH is under-recognised in primary care settings, and the pattern is counterintuitive: patients present with worsening headache, which logically suggests they need more or stronger treatment. Without understanding the role of medication overuse in driving the chronification of headache, the natural prescription response is to increase treatment intensity rather than reduce it. The solution is specialist review at a headache clinic, where the complete medication history is analysed in the context of the headache pattern. Many primary care doctors are also constrained by time pressures that make a detailed headache diary review difficult in a 10-minute appointment.

Yes. MOH is recognised in children and adolescents with pre-existing migraine who take acute medications too frequently. The diagnostic thresholds are the same as in adults. Paediatric MOH is managed with the same withdrawal approach, with adjustments for age-appropriate bridge and preventive therapies. If your child has daily headache and is regularly taking OTC analgesics or triptans, paediatric neurology or specialist headache review is warranted.