Chronic migraine

CHARM study
Between November 2012 and March 2016, the CHARM study (Chronification and reversibility of migraine) was conducted at the LUMC. This study primarily investigated the effect of botulinum toxin A as treatment of chronic migraine. Chronic migraine is a highly disabling form of migraine, affecting around 500.000 patients in the Netherlands. It is defined as headache occurring on at least 15 days per month, of which on at least 8 days the headache meet the migraine criteria. Most of these patients use too much acute headache medication and thus are at risk for medication overuse headache. 

TreatmentCurrent treatment of chronic migraine with medication overuse comprises of acute abstention from pain medication for a period of 2-3 months, resulting in a reduction of headache frequency in most patients. However, acute abstention is difficult to endure, due to withdrawal symptoms and untreated headaches. Withdrawal symptoms typically appear in the first days to weeks, before the headache frequency and severity diminish. The objective of the CHARM study was to assess whether add-on therapy with Botulinum toxin A enhances the efficacy of acute withdrawal and makes it more easy to endure.


From December 2012 to February 2015, 179 participants were enrolled in the study and randomly received Botulinum toxin A or placebo in combination with acute abstention from pain medication. The true effect of the study medication could be assessed by comparing the two groups. Participants were followed up to one year after treatment.

As part of the CHARM study, imaging (100 participants) or blink reflex measurements (80 participants) were performed before treatment,  three months after and one year after treatment. 

Currently, all participants have completed the study and we are analysing the data. The results will be announced through our Dutch newsletter, and shared on this website.