Introduction

Fibromyalgia (FMS) is a chronic syndrome characterized by widespread pain, troubled sleep, disturbed mood, and fatigue. Analgesic treatment has shown moderate and inconsistent results whereas antidepressants have become the treatment of choice. Studies have shown that FMS may be associated with a deficit of carnitine which may affect liver, heart and skeletal muscle functioning leading to weakness, fatigue, and exercise intolerance. L-carnitine may have a role in reducing the hypoxic stress of tissues. L-acetylcarnitine (LAC) therapy has been shown to be effective in mood disturbances and depression.

Aim

To evaluate the efficacy of acetyl L-carnitine (LAC) in patients with overt FMS

Patient Profile

• 102 patients with overt FMS (presence of at least 11 positive trigger points with pain)

Method

Study Design

• Double-blind, randomized multicenter trial
• Treatment was double blind and double dummy throughout; patients were treated with 2 capsules/day of 500 mg LAC or placebo plus one intramuscular injection of either 500 mg LAC or placebo for 2 weeks
• During the following 8 weeks the patients took 3 capsules daily containing either 500 mg LAC or placebo
• The patients were visited during treatment after 2, 6 and 10 weeks and also 4 weeks after treatment discontinuation (follow-up visit)

Endpoints

• Primary end point: total myalgic score and number of positive tender points
• Secondary end point: a 100 mm visual analog scale (VAS) for self-perceived stiffness, fatigue, tiredness on awakening, sleep, work status, depression, and muscular-skeletal pain, and the Hamilton depression scale, the Short Form 36 (SF36) questionnaire

Results

Efficacy

• Acetyl L-carnitine (LAC) significantly and equally lowered the total myalgic score and the mean number of positive tender points (<4 kg pain threshold) in both, treatment and placebo groups, until the 6th week of study
• At the 10th week, both these parameters continued to improve in LAC group but remained unchanged in placebo group, with a significant between-group difference (p <0.02), both for the absolute number and with regards to its change
• Most VAS scores significantly improved in both groups; significant between-group difference was observed for depression and musculoskeletal pain
• Significantly larger improvements in 7 out of 10 parameters of SF36 questionnaire were observed in LAC and in 3 out 10 parameters in the placebo group, respectively
• Further, in the SF36 questionnaire, significant between-group differences were observed for bodily pain, mental health, general health perception and both mental and physical total scores
• The mean Hamilton score significantly improved in the LAC group at week 10

Safety 

• LAC treatment was well tolerated
• Adverse events (AE) were similar in the two groups of patients (42% in placebo group vs. 36% in LAC group)
• AE led to treatment discontinuation for 3 and 5 subjects of the placebo and LAC group, respectively

Conclusion

LAC was beneficial in patients with FMS, providing improvement in pain as well as the general and mental health of patients

Clin Experimental Rheumatol 2007; 25: 182-188