Botulinum toxin for chronic pain: What's on the horizon?

A small case series conducted soon after BoNT was introduced showed promising results, and subsequent meta-analyses and systematic reviews have shown positive results for use of BoNT for the management of spasticity.¹³ Studies have begun to focus on specific regions of the upper and lower limbs to identify optimal sites for injections.

Cervical dystonia

Cervical dystonia (CD) is the most common form of dystonia and is defined as impairment of activities of daily living due to abnormal postures of the head and neck. BoNT was approved for CD in 1999 after several pivotal randomized placebo-controlled ­double-blind studies showed improvement of symptoms.¹⁴ Several BoNT formulations have been given Level A classification, and can be considered a potential first-line treatment for CD.^15,16 The most common adverse effects reported have been dry mouth, dysphagia, muscle weakness, and neck pain.^14-16

Recent metaanalyses evaluating knee and shoulder pain have shown BoNT is safe and effective for joint pain.

BoNT is currently being used off-label for management of multiple types of dystonia with reported success, as research on its use for noncervical dystonia (including limb, laryngeal, oromandibular, and truncal) continues. Although there are case series and some randomized trials exploring BoNT for certain types of dystonia, most are lacking high-­quality evidence from double-blind, randomized controlled trials.^14-16

Exploring the evidence for emerging indications

There has been significant interest in using BoNT for management for both nociceptive and neuropathic pain symptoms.⁵

Nociceptive pain is the irritation and painful response to actual or potential tissue damage. It is a major component of chronic pain and is difficult to treat, with limited effective options.^5,17

Continue to: Neuropathic pain