Assessment of the efficacy of lisdexamfetamine on fatigue in patients with multiple sclerosis: A randomized, double-blind, placebo-controlled study.

Objective: This trial was designed to evaluate the effect of lisdexamfetamine (LDX) on fatigue in patients with multiple sclerosis (MS).

Methods: The present study was a randomized, double-blind, placebo-controlled trial. MS patients who reported fatigue and had modified fatigue impact scale (MFIS) score greater than 33 were randomly assigned to receive LDX or placebo capsules for eight weeks. Patients received LDX or identical placebo capsules at a dose of 30 mg/day for the first month, which was then increased to 50 mg/day in the second month. The fatigue severity was assessed as a primary outcome during the trial.

Results: 62 patients entered the study; of these, 31 received LDX capsules and 31 received placebo capsules. Finally, 48 patients (24 in each group) were analyzed at the end of the study. No significant difference was reported between the MFIS score in LDX and placebo groups. Intra-group analysis showed significant improvement in MFIS score in both groups. However, the mean change in MFIS score was superior in patients receiving LDX 50 mg/day compared to the placebo group (P-value = 0.003).

Conclusions: LDX did not demonstrate superior efficacy in improving fatigue compared to placebo. Nonetheless, a significant mean change in MFIS score was observed in the LDX group at a dose of 50 mg/day. Further studies with higher doses and longer follow-up periods are warranted to better evaluate LDX efficacy.