Comparison of the efficacies of oral iron and pramipexole for the treatment of restless legs syndrome patients with low serum ferritin

Abstract

Background and purpose: It is not clear which is preferred between iron supplement and a dopamine agonist in the treatment of restless legs syndrome (RLS) with iron deficiency. The efficacies of oral iron supplementation and pramipexole for treatment of RLS with low-normal serum ferritin (15-50 ng/ml) were compared.

Methods: Thirty RLS patients who took either oral iron or pramipexole for 12 weeks and were followed at 2, 4, 8 and 12 weeks after treatment commencement were enrolled. Severities of RLS symptoms were assessed using the international RLS study group rating scale for severity (IRLS) at every visit. Treatment response was defined as a decrease in IRLS score of at least 50% from baseline.

Results: The 30 subjects were assigned equally to an iron or pramipexole group. At baseline, IRLS scores and serum ferritin levels were similar between these two groups. After 12 weeks, IRLS scores were lower than those at baseline in both groups (iron -9.1 ± 7.07, P < 0.001; pramipexole -8.7 ± 8.31, P = 0.001) and similar between the two groups. Changes in IRLS scores from baseline were similar between the two groups at each visit. The response rates of the groups were identical at 46.7%.

Conclusions: Pramipexole was not different from oral iron in terms of efficacy and improvement speed in RLS patients with a low-normal serum ferritin, but response rate of either oral iron or pramipexole alone was moderate. Some proportion of RLS patients with iron deficiency might benefit from combined use of oral iron and dopamine agonists.

Keywords: dopamine agonist; ferritin; iron; pramipexole; restless legs syndrome.