Medication-overuse headache (MOH) is a common, costly and disabling disorder affecting approximately 63 million people worldwide. MOH is a potentially treatable condition, and there are different opinions among headache specialists concerning the correct treatment strategy.

The study is a prospective longitudinal open-label randomized controlled study comparing two detoxification programs conducted in a tertiary headache care center. Patients with MOH are either randomized to treatment in program A or program B. In program A, patients undergo detoxification without any acute medication during a two months period (complete stop of acute medication intake). In program B, patients was allowed to take up to 2 days a week with analgesics or migraine medication during the two months detoxification period (restricted acute medication intake). Both A and B are out-patient programs, and patients in both groups receive patient education, consisting of six lessons, managed by specialized headache nurses in collaboration with specialized psychologists and physiotherapists (Figure 1). All patients are also offered rescue medication (levomepromazine or promethazine) and antiemetics, if necessary.

The need for prophylactic treatment is evaluated individually after 2-month detoxification. Patients are followed-up at 2, 6 and 12 months after detoxification. All patients are asked to continuously register headache calendar and to fulfill questionnaires at all the follow-up visits. In addition they are asked to fill out questionnaires (Headache Under-Response to Treatment (HURT), Hospital Anxiety and Depression Score (HADS), Severity of Dependence Score (SDS), World Health Organization Quality of Life Score(WHO QoL) and Dolo-score) at baseline, 2, 6 and 12 months

Patients with contact to Danish headache center are recruited consecutively. The MOH-diagnosis is based on least 3 months previous detailed history and at least 1 month fulfilled headache diary or headache calendar prior to the visit.

Patients were allocated to either program A or B by a concealed randomization process. The patients were randomized in blocks of 10 by use of opaque, sealed envelopes.

Statistics Statistical Package for Social Sciences (SPSS) version 22 is used for statistical calculations. Continuous variables are presented as mean (SD) and median (25-75 percentiles). For normal distributed continuous variables the investigators use paired and unpaired student's T-test, while for skewed distribution the investigators used Mann-Whitney test. Categorical variables is presented as percentage (N), and analyzed by chi-square test. All results are shown as intention-to-treat (ITT). The p-value is two-sided and p ≤ 0.05 is considered as significant.

The primary outcome is reduction in headache days per month. Clinical relevant difference is estimated to 20% between the two groups. The standard deviation based on previous published literature was estimated to 35%. Accepting an alfa-error on 5% and 80% power, 80 patients are needed. Based on previous studies, it is assumed that the drop-out rate will be approximately 15-20%. Therefore the investigators aim to include 100 patients corresponding to 50 in each group.

Inclusion Criteria:

• MOH-diagnosis according to ICHD-3beta
• Eligible for out-patient care
• Previously diagnosed with primary headache forms.

Exclusion Criteria:

• Previously diagnosed with secondary headache forms
• Significant physical or psychiatric illness
• Pregnancy or breastfeeding
• Inadequate language skills to follow the patient education and filling out questionnaires.