Medication-overuse headache: causes, consequences and management

Abstract

Medication-overuse headache (MOH) has a prevalence of approximately 1% and is among the top 20 causes of disability worldwide, leading to considerable medical, social, and economic costs. It is defined in the International Classification of Headache Disorders (ICHD-3) as a headache occurring on at least 15 days per month in someone with a pre-existing headache disorder and developing as a result of regular overuse of one or more acute/symptomatic headache treatments for at least 3 months. Overuse is defined as at least 10 days per month for triptans, opioids and ergotamine, or at least 15 days per month for paracetamol, aspirin, and non-steroidal anti-inflammatory drugs. The frequency of acute medication use seems more important in the development of MOH than the cumulative dosage taken. MOH most often develops in those with underlying migraine or tensiontype headache, but it can occur with other primary headache disorders such as cluster headache or new daily persistent headache. The quality of the headache is often similar to that of the underlying headache disorder which can make diagnosis of MOH difficult unless symptomatic improvement after acute drug withdrawal is observed. Women are four times as likely to develop MOH as men with peak prevalence at age 40–50. Other risk factors associated with MOH include obesity, anxiety or depression, low educational level, smoking, chronic musculoskeletal or gastrointestinal diseases, and physical inactivity. Treatment strategies include drug withdrawal, with or without preventive medication cover, and patient education. This month’s journal club examines three papers reporting on the causes, consequences and treatments of MOH. The first is a systematic review and critical appraisal of gene polymorphism association studies, assessing the evidence for genetic predisposition to MOH. The second examines association between MOH and suicidal ideation and the third reports an open-label, randomized clinical trial of three treatment strategies.