Background Medication-overuse headache (MOH) is common in the general population. We investigated effectiveness of brief intervention (BI) for achieving drug withdrawal in primary care patients with MOH.

Methods The study was double-blind, pragmatic and cluster-randomised controlled. A total of 25 486 patients (age 18–50) from 50 general practitioners (GPs) were screened for MOH. GPs defined clusters and were randomised to receive BI training (23 GPs) or to continue business as usual (BAU; 27 GPs). The Severity of Dependence Scale was applied as a part of the BI. BI involved feedback about individual risk of MOH and how to reduce overuse. Primary outcome measures were reduction in medication and headache days/month 3 months after the intervention and were assessed by a blinded clinical investigator.

Results 42% responded to the postal screening questionnaire, and 2.4% screened positive for MOH. A random selection of up to three patients with MOH from each GP were invited (104 patients), 75 patients were randomised and 60 patients included into the study. BI was significantly better than BAU for the primary outcomes (p<0.001). Headache and medication days were reduced by 7.3 and 7.9 (95% CI 3.2 to 11.3 and 3.2 to 12.5) days/month in the BI compared with the BAU group. Chronic headache resolved in 50% of the BI and 6% of the BAU group.

Conclusions The BI method provides GPs with a simple and effective instrument that reduces medication-overuse and headache frequency in patients with MOH.

Trial registration number NCT01314768.