Abstract
Dear Sir A recent Editorial by Evers and Olesen (1) concluded that ‘botulinum toxin A has no role in the prophylactic treatment of episodic infrequent migraine and tension-type headache’. The basis for this conclusion regarding tension-type headache is weak, but it is even weaker for episodic migraines. The authors review three migraine studies, of which one with 123 patients was positive (2) and two, with 30 and 60 patients, were negative (3, 4). Even if this was referring to an oral drug such a conclusion would have been unfounded, but since we are talking about injectable therapy, where the dose and the site selection have not been worked out, such a conclusion seems completely unjustified. One of the editorialists is also the lead author of the 60-patient negative study which used an unusual selection of injection sites (very small amounts injected into temporalis and frontalis muscles) and which, contrary to the International Headache Society Guidelines, allowed patients on other prophylactic drugs into the study. Only 35 out of 90 patients in the two negative studies were on active treatment.
Our positive experience treating hundreds of migraine patients with botulinum toxin A over the past 10 years (and similar experience of many other headache experts in the USA) cannot serve as proof of efficacy. However, making definitive negative conclusions on the basis of small amounts of weak data is also inappropriate.