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Restless Legs and Akathisia
Definition
- 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.
- Drugs that block the action of dopamine may cause akathisia Involuntary Movements.
Predisposing factors
- 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 effect has been obtained with small evening doses of dopaminergic drugs (pramipexole 0.09-0.36 mg, ropinirole 0.25-3 mg). The adverse effects of long-term therapy are not known.
- 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]