Botulinum toxin type A injections for myofascial pain syndrome and tension-type headache

Myofascial pain syndrome (MPS) is characterised by acute and specific pain affecting the piriformis, iliopsoas or scalenus anterior muscles. Tension-t ype headache (TH) is a common pathological condition, which can be chronic or episodic. Based on its muscle-relaxant properties, botulinum toxin type A (BTX-A) has demonstrated efficacy in a variety of conditions involving dy sregulated muscle contractions. Patients with MPS (n = 40) or TH (n = 20) w ere recruited to two randomised, single-blind studies, respectively, Each p atient received either BTX-A or methylprednisolone, injected into the affec ted muscles after administration of a local anaesthetic. Pain was assessed at baseline, and 30 and 60 days post-treatment using a standard visual anal ogue scale. At 30 days post-injection, the mean pain score in all treatment groups was reduced compared with baseline in both studies, although the di fference between treatment groups was not significant at this time in eithe r study. However, by 60 days post-injection, the mean pain score has contin ued to fall in the BTX-A treatment groups, compared with a waning of the st eroid therapeutic activity in the controls. The net effect was a highly sig nificant difference between the two treatments in both the MPS (P < 0.0001) and TH (P < 0.0005) studies. No major adverse events were reported. In con clusion, BTX-A produces a more prolonged pain relief than methylprednisolon e in patients suffering from MPS or TH. Eur J Neurol 6 (suppl 4):S103-S109 (C) Lippincott Williams & Wilkins.