This trial is active, not recruiting.

Condition pain
Treatments botulinum toxin a, placebo - saline
Sponsor Stanford University
Start date December 2007
End date October 2012
Trial size 70 participants
Trial identifier NCT00725322, 11830, SU-01072008-965


Superficial injection of Botulinum toxin has been advocated for cosmetic purposes but has also been reported to be helpful for some pain conditions. The investigators have observed prolonged profound analgesia following subcutaneous superficial injection of Botulinum Toxin Type A (BTA) in patients with certain types of neuropathic pain. The investigators propose to study if addition of BTA extends pain relief compared to placebo when injected subcutaneously into areas of cutaneous allodynia (the property that a normally non-noxious stimulus is perceived as painful).

United States No locations recruiting
Other Countries No locations recruiting

Study Design

Allocation randomized
Endpoint classification efficacy study
Intervention model crossover assignment
Masking double blind (subject, investigator, outcomes assessor)
Primary purpose treatment
(Placebo Comparator)
placebo - saline
Subcutaneous Saline injection given at site of scar neuroma
botulinum toxin a
Subcutaneous injection of Botulinum Toxin Type A into the patient's scar tissue

Primary Outcomes

Time until analgesic failure
time frame: duration of trial

Secondary Outcomes

Reduction in area of allodynia and hyperalgesia
time frame: duration of trial
Improvement in psychosocial function as assessed by outcomes as dictated by the IMMPACT guidelines
time frame: duration of trial
Proportion of patients experiencing a reduction of 2 points or more on NRS, three weeks after injection compared to baseline NRS
time frame: duration of trial

Eligibility Criteria

Male or female participants at least 18 years old.

Inclusion Criteria:- Moderate to severe pain (greater than 4/10) of duration more than 6 months despite previous therapy. - The patient exhibits at least 80% pain relief following injection of local anesthetic subcutaneously into scar as assessed by change in NRS - The patient reports the presence of hyperalgesia, allodynia, dysesthesia, or hypoesthesia surrounding the scar - Age 18-100 - Ability to read, write, and converse in English, provide informed consent, and follow study procedures Exclusion Criteria: 1. Any neuromuscular disorder such as myasthenia gravis, eaton lambert, muscular dystrophy 2. Any ongoing legal action related to their pain 3. Allergy to local anesthetics 4. A current or history of any severe psychiatric disorder 5. History of any adverse reaction to botulinum toxin 6. History of botulism 7. Untreated infection 8. Coagulopathy 9. Females - positive pregnancy test 10. Surgery within the past 6 months at the site of the painful scar

Additional Information

Official title Subcutaneous Botulinum Toxin for Cutaneous Allodynia
Principal investigator Ian R Carroll
Description Post-surgical neuromatous pain patients have marked cutaneous allodynia. Touching their skin with normally non-painful stimuli results in pain. Injected local anesthetics are often effective in providing temporary relief. In the course of clinical practice the investigators have observed that a number of patients with cutaneous allodynia have had marked persistent benefit from subcutaneous injection of Botulinum toxin Type A. Rather than killing targeted neurons, Botulinum toxin type A inhibits release of acetylcholine from cholinergic nerve terminals in a prolonged but ultimately reversible manner. Neuropathic pain and its hallmark allodynia are classically difficult to treat. Standard treatment with tricyclic antidepressants, anti-epileptic drugs, opiates and spinal cord stimulation is frequently disappointing leaving patients with refractory pain. Surgical or percutaneous ablation of involved nerves has fallen out of favor among many due to disappointing results. A pilot study is needed to assess the efficacy of superficially injected Botulinum Toxin type A for treatment of cutaneous allodynia and spontaneous pain among patients with neuropathic pain.
Trial information was received from ClinicalTrials.gov and was last updated in June 2012.
Information provided to ClinicalTrials.gov by Stanford University.