The International Classification of Headache Disorders (ICHD) defines medication overuse headache as:

• Headache occurring on 15 or more days per month in a person with a pre-existing primary headache disorder, which develops as a consequence of regular overuse of one or more drugs that can be taken for acute and/or symptomatic treatment of headache, for more than 3 months. It usually, but not always, resolves after the overused medication is stopped.
  • Ergotamines, triptans, opioids, or combination analgesics are taken on 10 days or more per month.
  • Simple analgesics such as paracetamol, nonsteroidal anti-inflammatory drugs (NSAIDs), or aspirin (either alone or in any combination) are taken on 15 days or more per month.

Management

Withdrawing from medication overuse in primary care:

• Advise to stop taking all overused acute headache medications for at least 1 month.
• simple analgesics and triptans should be withdrawn abruptly (may initially worsen headaches)
• opioid analgesics should be gradually withdrawn
• Advise to keep a headache diary to measure the frequency, duration, and severity of headache and medication use during withdrawal.

Drug withdrawl:

• Advise there may be initial worsening of headache and other withdrawal symptoms for 1–2 weeks during and after drug withdrawal, so the timing of withdrawal should be planned according to the person's lifestyle and commitments.
  • Other possible withdrawal symptoms include nausea, vomiting, reduced appetite, hypotension, tachycardia, sleep disturbance, anxiety, and restlessness.
• Advise that headache usually improves 1–2 weeks after drug withdrawal but recovery may continue for 2–3 months.