Acetyl-L-carnitine for fibromyalgia.

One hundred and two patients with fibromyalgia were randomly assigned to receive, in double-blind fashion, acetyl L-carnitine (ALC) or placebo for ten weeks. During the first two weeks, patients received daily 1,000 mg orally and 500 mg intramuscularly. During the next eight weeks, the patients received 1,500 mg per day orally. After ten weeks, the improvements in depression, musculoskeletal pain, number of tender points, and total symptom score were significantly greater in the ALC group than in the placebo group. No significant difference was seen between groups after six weeks. ALC was well-tolerated.

Comment: These findings suggest that ALC is an effective treatment for fibromyalgia, although treatment has to be continued for a substantial period of time before improvement is seen. It is probably not necessary to begin treatment with intramuscular injections, as was done in the present study, since orally administered ALC has demonstrated a wide range of beneficial effects, including improvement in memory, fatigue, and Peyronie's disease. While the mechanism of action of ALC is not clear, it appears to function as a neurotransmitter. In addition, the carnitine component of ALC may enhance energy metabolism by promoting the uptake of fatty acids into mitochondria. ALC is generally well-tolerated, although it was reported in one study to cause nausea and vomiting in more than one-quarter of patients with Alzheimer's disease.

Rossini M, et al. Double-blind, multicenter trial comparing acetyl l-carnitine with placebo in the treatment of fibromyalgia patients. Clin Exp Rheumatol. 2007;25:182-188.

by Alan R. Gaby, MD

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