Page 82 - The clinical aspects and management of chronic migraine Judith Anne Pijpers

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Chapter 4
Discussion
We assessed whether double-blind add-on therapy of Botulinum toxin A (BTA) increased efficacy of acute withdrawal in chronic migraine with medication overuse. Efficacy was evaluated primarily after 12 weeks, as this period comprises the acute withdrawal phase. Low doses of BTA in the forehead of placebo- treated participants successfully prevented unblinding. Acute withdrawal was well-accepted and associated with meaningful improvement. BTA did not afford any additional benefit over withdrawal alone.
Most patients with chronic migraine overuse acute headache medications1,2,21–24,42 and withdrawal may significantly reduce headache.1,4,6–8,17,43 Yet, many patients and physicians are reluctant to initiate withdrawal fearing acute withdrawal symptoms.1–3,7,15,16 In our study, 90% of the study population completed withdrawal, almost 50% evaluated their therapy as very good, and 70% would recommend their therapy to friends and family. After withdrawal, mean number of headache days had decreased by approximately 5 days (≈ 25%) and of migraine days by 6-7 days (≈ 45%; Table 2). In total 60% of patients had reverted back to episodic migraine, which was mainly due to the large drop in migraine days below the threshold of 8 days required to fulfill the criteria for chronic migraine (Figure 3). Over 30% of participants (29% in the Botulinum toxin A group and 34% in the placebo group) did not need preventive medication anymore as their number of migraine days had dropped below 4 per month. These results confirm that withdrawal is well-tolerated and associated with meaningful improvement.
Comparison with results from other studies is difficult because of different study designs and populations. For instance, many studies1,4–7,9–13 were conducted in patients who had medication overuse headache, but not necessarily chronic migraine. In a study in patients with medication overuse of whom 60% fulfilled the criteria for chronic migraine,8 acute withdrawal resulted in a reduction in mean monthly migraine days and a reversion to episodic migraine very similar to what we found in our study.
In the PREEMPT studies, patients with daily headaches and/or comorbid depression were excluded because they are more treatment-resistant. In our