Overview
Medication overuse headaches (MOH) are a common cause of secondary headaches. They should be considered when a patient has a headache for >15 days per month which has worsened while taking medication for it.
Epidemiology
- Most common type of headache after tension-type headaches and migraines
- 1/5 of patients with chronic headaches have MOH
- Low doses daily have a higher risk than larger doses weekly
- Affects women more than men
Causes
- Opiates (e.g. codeine) cause problems most frequently
- Triptans
- Ergotamine
- NSAIDs are less likely to cause MOH
Risk Factors
- Chronic headache
- Medication overuse for headache
- Female sex
Presentation
Patients usually have a chronic headache (occurring >15 days per month) with overuse of pain relief. The headache usually worsens or does not resolve despite taking the medication:
- They may find that the headache worsens when attempting to withdraw the medication
Differential Diagnoses
Migraine
- The pain is usually unilateral and pulsatile/throbbing
- There is usually associated nausea
- The pain is usually worse with activity and severe
- Patients often feel like they need to rest in dark and quiet rooms and try to sleep off the headache
They can often co-exist
Tension-type headache
- They can often co-exist and may be hard to differentiate based on clinical features
Management
- 1st–line: withdrawal of analgesia – how quickly depends on what is used:
- Simple analgesia and triptans – abruptly withdraw, even if it worsens the headache
- Opioid analgesia – gradually withdraw
Monitoring and Patient Advice
Monitoring
- Patients should be followed for 4-8 weeks after withdrawing the overused medication
- If relapses occur, offer psychological therapies such as CBT
Patient Advice
Patients should be notified that withdrawal can initially worsen the headache but this improves with time. Some features of withdrawal can be:
- Nausea/vomiting
- Tachycardia
- Restlessness
- Sleep problems
- Anxiety
- Patients should be advised on the risk of medication overuse headaches
- Patients should keep headache diaries recording the frequency, severity, characteristics, and duration of the headaches, along with the effectiveness of medications – this can help if the diagnosis needs to be reconsidered
Complications and Prognosis
Complications
- Decreased quality of life
- Psychosocial complications e.g. depression
Prognosis
- Most patients improve after stopping the overused medication
- The headache usually starts to improve within 2 weeks and then continues over weeks to months
- Relapse is most likely to happen within the first year of withdrawal
