Botulinum type A toxin (BoNT-A) or Botox has been used in research trials for myofascial pain syndrome (MPS). Some studies have used Botox® while others have used a product called Dysport®. This product is not the same as Botox®. Dysport® has three times the dosage of Botox®.
Both types of botulinum type A toxin have been shown effective. Pain is reduced and sometimes eliminated. The benefit isn't immediate but occurs about four to six weeks after the treatment.
Some scientists have questioned whether it's just the needle being inserted that gives the pain relief. Studies to look at this question compared injections of lidocaine (numbning agent) versus just dry needling. Patients receiving the lidocaine had much better reduction in their pain levels.
More study is needed to find out what works and why. Botox injections are not routinely available for this problem. Most of the research being done on using Botox for MPS is taking place in Europe.