Low-dosed Botulinum Toxin A in the Prophylactic Management of Unilateral Migraine: A Randomized Double-blind Placebo-Controlled Crossover Study

Botulinum toxin is a therapeutic option in chronic migraine. No dose-finding studies have been conducted so far. Some authors maintain that one injection into the corrugator muscle will do. Objective: We studied the effect of Botulinum toxin (BTX) injections in patients with strictly unilateral migraine. Methods: We treated 22 patients (ITT) in a crossover design for 4 months with 2 x 5 units Onabotulinum toxin (in the cor- rugator and occipitalis muscle ipsilaterally). Aside from patient data, we also gathered information on undesired drug ef- fects, besides IQOLA SF36, SF-MPQ SADP, OLBPDQ, VAS (pain intensity and daily living skills), PPI, frequency of at- tacks and application of medication. The statistical evaluation was guided by SPSS (V.13). Results: Assessed were 19 patients (PP) aged 45.2 ± 11.1 years, thereof 17 women. In both injection intervals there were no clinically relevant and/or statistically significant differences as to the target parameters (for example: VAS pain inten- sity p=0.702), with a notably evident placebo effect (VAS in placebo prior to the injection was 61.4, after 6 weeks 45.1; good or excellent improvement (TOQ) was quoted by 36.8% after 6 weeks in the placebo group). BTX merely proved su- perior in two aspects: Regarding the pain quality "throbbing" (SF-MPQ SADP), 11 patients initially indicated a pro- nounced intensity; after BTX only 4 of them did. As to the severity of the pain felt, (PPI) 42.2 of the subjects described "limiting" or "horrible" pain prior to the injection versus 26.3% six weeks after the injection and 21.1% 4 months later. The placebo group started out with 31.6%, that figure remaining the same (31.6%) 6 weeks later, rising to 42.2% after 4 months. 84.2% of the BTX-group and 63.2% in the placebo group requested a reinjection when the study was completed. Conclusion: The injection of low-dosed Botulinumtoxin A did not show any relevant or significant effects in patients with unilateral migraine without aura. One injection into the corrugator muscle alone must be considered as ineffective. The place-value of the two injection sites remains in the open.