Small study shows improvement with injections after 2 weeks
An uncontrolled prospective before-after study in 1996 evaluated the effectiveness of 0.5% lidocaine trigger point injections in 9 patients with myofascial trigger points plus fibromyalgia compared with 9 patients with myofascial trigger points alone.2
Immediately after injection, patients with fibromyalgia had a nonsignificant worsening in pain intensity (pain scale 8.1 to 8.4/10; P>.1), but there was a significant improvement at 2 weeks (5.9; P<.01). The pressure threshold also decreased initially (1.7 to 1.4 kg/cm2; P>.1), but significantly increased at 2 weeks (2.4 kg/cm2; P<.01). In comparison, patients without fibromyalgia showed immediate improvement in all domains, which persisted at 2 weeks (P<.01).
What the guidelines say
Recent Canadian Fibromyalgia Guidelines discuss trigger point injections in the section on “off-label” medications, stating that they “may have some place in treatment of fibromyalgia.”3