Clinical features of probable medication-overuse headache: a retrospective study in Japan.

This study examined the clinical picture of probable medication-overuse headache (MOH) and the presence of any features peculiar to Japan. In a retrospective study of 47 patients, type of primary headache, type of medicine overused, method and result of withdrawal were investigated. Among the 47 patients, 80.9% had migraine only, and 85.1% overused combination medications. While 36 patients (76.6%) succeeded in withdrawal, five patients (10.6%) failed. One patient (2.1%) had not improved by 2 months after withdrawal and was diagnosed with chronic migraine and chronic tension-type headache without MOH. The remaining five patients (10.6%) dropped out. All dropout patients were recommended abrupt inpatient withdrawal, but chose abrupt outpatient withdrawal. As features peculiar to Japan, many patients with probable MOH overused combination analgesics, particularly females.