Myotoxicity of injections for acute muscle injuries: a systematic review

Injection therapies are widely used for muscle injuries. As there is only limited evidence of their efficacy, physicians should be aware of the potential harmful effects of these injected preparations. The purpose of this review was to systematically review the literature on the myotoxic effects of intramuscular injection preparations commonly used for acute muscle injuries. The databases of PubMed, Embase, Web of Science, Cochrane Library, CINAHL and SportDiscus were searched in March 2013. Studies reporting histological evaluation or creatine kinase activity after intramuscular injection with local anaesthetics, corticosteroids, non-steroidal anti-inflammatory drugs (NSAIDs), platelet-rich plasma (PRP), Traumeel(®) and Actovegin(®), or combination preparations were eligible for inclusion. Two authors independently screened the search results and assessed the risk of bias. A best-evidence synthesis was used to identify the level of evidence. Forty-nine studies were included in this systematic review. There is strong to moderate evidence that intramuscularly injected local anaesthetics and NSAIDs are myotoxic, and there is conflicting evidence of the myotoxicity of PRP. There is limited evidence that single corticosteroid injections are not myotoxic but have a synergistic myotoxic effect when used together with local anaesthetics. There is no information to assess whether Actovegin(®) and Traumeel(®) are myotoxic. Local anaesthetics and NSAID injections are not recommended for the treatment of muscle injuries in athletes, as they are myotoxic. The possible myotoxic effects of corticosteroids, PRP, Traumeel(®) and Actovegin(®) should be assessed in future researc