Restless legs syndrome is a condition in which the patient experiences nocturnal, unpleasant sensations in the lower extremities alleviated by moving the legs. The condition may result in serious insomnia.
Pregnancy, aging, scarcity of storage iron, uraemia, and family history of idiopathic symptoms may be the underlying causes of restless legs syndrome.
Akathisia usually begins immediately after or within a few weeks of starting a predisposing medication.
Tests
Clinical examination of the lower extremities (oedema, varicose veins, eczema due to varicosis, patency of arteries, sense of touch, muscle atrophy)
If restless legs syndrome is suspected, plasma ferritin should be checked.
If the concentration is in the lowest third of the reference range that is considered normal in investigation for anaemia, iron supplementation may be beneficial.
In that case, the aim is to raise the ferritin concentration to the highest third of the reference range.
If necessary, plasma creatinine should be checked.
When considering the initiation of dopaminergic medication, the patient should be asked about possible earlier psychotic symptoms and an assessment of susceptibility to psychosis should be made.
Instructions for improving sleep hygiene and iron supplementation are not always enough to calm restless legs. In mild cases a hypnotic or a low dose of benzodiazepine may be beneficial but the adverse effects may exceed the benefits. Potent, short-acting benzodiazepines should be avoided.
Good therapeutic results have been achieved with 300 mg of pregabalin.Gabapentin may be useful especially in painful cases.
In severe cases opioids such as tramadol 50-100 mg in the evening have been used.
If akathisia is suspected, the dose of the predisposing drug is reduced or the drug is changed for a preparation with a stronger 5-HT2 receptor blocking effect.
So-called new generation antipsychotics have a stronger 5-HT2 blocking effect.
The worst antidepressant in this respect is probably mirtazapine which may usually be replaced with another medication. The mechanism is more complex than that of antipsychotics.
If necessary a short course of propranolol 20 mg × 3, biperiden 1-2 mg × 3 or small doses of benzodiazepine may be used.
References
Garcia-Borreguero D, Kohnen R, Silber MH et al. The long-term treatment of restless legs syndrome/Willis-Ekbom disease: evidence-based guidelines and clinical consensus best practice guidance: a report from the International Restless Legs Syndrome Study Group. Sleep Med 2013;14(7):675-84. [PubMed]
Allen RP, Chen C, Garcia-Borreguero D et al. Comparison of pregabalin with pramipexole for restless legs syndrome. N Engl J Med 2014;370(7):621-31. [PubMed]