What is the role of botulinum toxin (BoNT) in pain management?

Updated: Jul 13, 2018
  • Author: Divakara Kedlaya, MBBS; Chief Editor: Elizabeth A Moberg-Wolff, MD  more...
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Answer

Use of BoNT-A in the management of different pain disorders is being studied. [115] At this time, indications for the use of BoNT in managing muscle pain disorders still are controversial. The exact mechanism of action behind BoNT's analgesic effect is not known; however, a study by Purkiss and colleagues showed that BoNT inhibits calcium-dependent release of substance P in embryonic dorsal root ganglia. [116] Hence, BoNT may, by blocking the release of substance P, produce an analgesic effect through peripheral inhibition of C and A delta fibers. Based on the research with animal models, BoNT-A in peripheral nociceptive neurons plays a direct role in its peripheral analgesic effect and an indirect role in its central analgesic effect because of retrograde transport. [117]

In a double-blind, randomized, placebo-controlled study, Foster and colleagues showed the efficacy of 200 U of BoNT-A injection, using 40 U per site at 5 lumbar paravertebral levels on the side of maximum discomfort, in chronic low back pain patients. [118]

A Cochrane review regarding the use of BoNT-A injection for chronic low back pain has concluded evidence that BoNT injections improved pain, function, or both better than saline injections was limited, as was evidence this was better than acupuncture or steroid injections. [119] They recommend further high quality randomized controlled studies.

BoNT-A injection has also been studied for chronic neck pain, cervicogenic headache, and whiplash-associated neck pain; however, a Cochrane review and systematic review and meta-analysis by Langevin et al concluded that current evidence fails to confirm either a clinically important or a statistically significant benefit of BoNT-A injection for whiplash-associated neck pain and chronic neck pain associated with or without cervicogenic headache. [120, 121]

BoNT-A has been studied to treat different neuropathic pain disorders such as postherpetic neuralgia, [122] trigeminal neuralgia, [123, 124] and diabetic peripheral neuropathic pain, [125] and has shown to be effective in managing pain in these conditions.

Different studies on the use of BoNT in the management of different pain disorders are listed in Table 3.

Table 3. Studies on the Use of Botulinum Toxin in Pain Management (Open Table in a new window)

Author(s) (Year)

Clinical Condition

Study Type

N

Results

Zwart et al (1994) [126]

Tension headache

Open-label

6

Unilateral temporal injection not effective

Sherman et al (1995) [127]

Chronic pancreatitis

Open-label

7

Not effective

Paulson et al (1996) [128]

Fibromyalgia

Randomized, controlled

5

Not effective

Wheeler et al (1998) [129]

Myofascial pain [130]

Randomized, double-blind, controlled

33

No significant difference, second injection effective?

Wheeler (1998) [131]

Tension headache

Open-label

4

Effective in 4 patients

Schulte-Mattler et al (1999) [132]

Tension headache

Open-label

9

Effective in 8 of 9 patients

Freund et al (1999) [133]

Temporomandibular disorders

Open-label

15

Effective

Freund et al (2000) [134]

Temporomandibular disorders

Open-label

46

Effective

Silberstein et al (2000) [135]

Migraine headache

Double-blind, vehicle-controlled

123

Effective prophylaxis

Rollnik et al (2000) [136]

Tension headache

Double-blind, placebo-controlled

21

Not effective

Freund et al (2000) [137]

Cervicogenic Headache

Randomized, double-blind, placebo-controlled

26

Effective

Freund et al (2000) [138]

Whiplash associated with neck pain

Randomized, double-blind, placebo-controlled

26

Effective

Barwood et al (2000) [139]

Severe postoperative pain and spasm in cerebral palsy

Randomized, double-blind, placebo-controlled

16

Effective prophylaxis

Porta (2000) [140]

Chronic myofascial pain syndrome

Randomized, controlled, comparative

40

BOTOX® better than methylprednisolone

 

For more information, see Medscape Reference article Botulinum Toxin in Pain Management.


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