Headache 2000 Jun;40(6):445-50

Botulinum toxin type A as a migraine preventive treatment.

For the BOTOX Migraine Clinical Research Group. Silberstein S, Mathew N, Saper J, Jenkins S Thomas Jefferson

University School of Medicine, Philadelphia, PA, USA.

OBJECTIVE: To assess the safety and efficacy of botulinum toxin type A (BOTOX; Allergan, Inc) in the prevention of migraine.

BACKGROUND: Current migraine preventive therapies are often unsatisfactory because of their limited efficacy, adverse effects, and drug interactions. Botulinum toxin type A injections often reduce the pain associated with conditions such as cervical dystonia, achalasia, rectal fissures, and myofascial pain syndrome. An open-label, noncontrolled study of botulinum toxin type A suggested benefits for patients with migraine.

DESIGN AND METHODS: This was a double-blind, vehicle-controlled study of 123 subjects with a history of two to eight moderate-to-severe migraine attacks per month, with or without aura. Participants were randomized to receive single administrations of vehicle or botulinum toxin type A, 25 U or 75 U, injected into multiple sites of pericranial muscles at the same visit. During a 1-month baseline period and for 3 months following injection, subjects kept daily diaries in which they recorded migraine frequency, migraine severity, and the occurrence of migraine-associated symptoms.

RESULTS: Compared with vehicle treatment, subjects in the 25-U botulinum toxin type A treatment group showed significantly fewer migraine attacks per month, a reduced maximum severity of migraines, a reduced number of days using acute migraine medications, and reduced incidence of migraine-associated vomiting. Both the 25-U and 75-U botulinum toxin type A groups were significantly better than the vehicle group on subject global assessment. Botulinum toxin A treatment was well tolerated, with only the 75-U treatment group exhibiting a significantly higher rate of treatment-related adverse events than vehicle.

CONCLUSIONS: Pericranial injection of botulinum toxin type A, 25 U, was found to be a safe treatment that significantly reduced migraine frequency, migraine severity, acute medication usage, and associated vomiting. Pain 2000 Mar;85(1-2):101-5 A comparative trial of botulinum toxin type A and methylprednisolone for the treatment of myofascial pain syndrome and pain from chronic muscle spasm. Porta M Pain Centre, Department of Neurology, Policinico San Marco, 24020, Zingonia/Bergamo, Italy. Myofascial pain syndrome (MPS) is a common illness, characterised by acute or chronic focal pain, muscle stiffness and fatigue. The pathophysiology of MPS remains unclear. Previous preliminary studies have demonstrated therapeutic efficacy of the muscle relaxant botulinum toxin type A (BTX-A) in the treatment of MPS. A single-centre, randomised trial compared the effects of BTX-A with the steroid methylprednisolone (both administered intramuscularly with 0.5% bupivacaine), in 40 patients suffering from chronic myofascial pain in the piriformis, iliopsoas or scalenus anterior muscles. Thirty days after receiving an injection of either BTX-A or steroid followed by post-injection physiotherapy, pain severity had decreased significantly from baseline in both treatment groups, with no significant difference between the two treatment groups. However, the baseline pain score was significantly higher in the BTX-A treatment group compared with the steroid group (7.9 vs. 7.3), and the reduction in pain score between baseline and 30 days post-injection was greater in the BTX-A group compared with the steroid group (-3.9 vs. -3.5; P=0.06). At 60 days post-injection, the pain severity score for the BTX-A-treated patients was statistically significantly lower than the pain score for the steroid-treated population (2.3 vs. 4.9). Furthermore, the reduction in pain score in the BTX-A group at 60 days post-injection was greater than at 30 days (-5.5 vs. -3.9), whereas the effect of the steroid had begun to wane. These results indicate the superior efficacy of BTX-A over conventional steroid treatment in patients suffering from MPS, when combined with appropriate physiotherapy.

Spine 1998 Aug 1;23(15):1662-6; discussion 1667

A randomized, double-blind, prospective pilot study of botulinum toxin injection for refractory, unilateral, cervicothoracic, paraspinal, myofascial pain syndrome.

Wheeler AH, Goolkasian P, Gretz SS Charlotte Spine Center, North Carolina, USA.

STUDY DESIGN: In a randomized, double-blind study, two dosage strengths of botulinum toxin type A were compared with normal saline injected into symptomatic trigger points in the cervicothoracic paraspinal muscles.

OBJECTIVES: To compare the effect of botulinum toxin type A injections with that of normal saline to determine the former's usefulness in the management of neck pain and disability.

SUMMARY OF BACKGROUND DATA: The results of several studies have suggested that botulinum toxin type A may reduce pain associated with myofascial pain syndromes.

METHODS: Thirty-three participants were divided randomly to receive either 50 or 100 units of botulinum toxin type A, or normal saline. Patients were re-evaluated over a 4-month period by assessment of their pain and disability and pressure algometer readings, and then offered a second injection of 100 units of botulinum toxin type A.

RESULTS: All three groups showed significant treatment effects as measured by a decline in the scores on the Neck Pain and Disability Visual Analogue Scale and an increase in the pressure algometer scores. Group differences were apparent only when the authors considered the number of patients who were asymptomatic as a result of the injections.

CONCLUSIONS: Although no statistically significant benefit of botulinum toxin type A over placebo was demonstrated in this study, the high incidence of patients who were asymptomatic after a second injection suggests that further research is needed to determine whether higher dosages and sequential injections in a larger cohort might show a botulinum toxin type A effect. Pain 1994 Oct;59(1):65-9 Botulinum toxin in the treatment of myofascial pain syndrome. Cheshire WP, Abashian SW, Mann JD Department of Neurology, University of North Carolina, Chapel Hill 27599. Six patients with chronic myofascial pain syndrome involving cervical paraspinal and shoulder girdle muscles received trigger point injections of botulinum toxin type A (Botox) or saline in a randomized, double-blind, placebo-controlled study. Four patients experienced reduction in pain of at least 30% following Botox, but not saline, injections, as measured by visual analog scales, verbal descriptors for pain intensity and unpleasantness, palpable muscle firmness, and pressure pain thresholds. Results were statistically significant. Botox, which inhibits muscle contraction by blocking the release of acetylcholine from peripheral nerves, appears to be an effective treatment for focal myofascial pain disorders.