AUGMENTATION & REBOUND
Two of the most frequently mentioned terms when speaking about RLS are Augmentation and Rebound. Professor K. Ray Chaudhuri has provided us with a definition for each of these.
Restless Legs Syndrome can be a complicated disorder and treatment may not be straightforward in many cases. The issue is also complicated by the fact that many doctors are not fully aware of the side effects related to the commonly prescribed drugs for RLS. Only three drugs are licensed for treatment of RLS and unlicensed treatments are often used based on clinical experience as well as literature reports. The common treatments, using dopamine replacement therapy (commonly dopamine agonists and levodopa preparations) may lead to complications. These problems are still poorly understood but need to be recognised in clinic.
One such problem is Augmentation, which also overlaps with the phenomenon of Rebound.
Augmentation is a complex and poorly understood phenomenon that is characterised by the earlier onset of symptoms - around the time the next scheduled dose of the drug used to treat RLS – and is associated with an increase in the overall severity of symptoms of RLS. The condition appears to start at a faster rate when one is resting and often the upper limbs (with or without the head and chin) may be involved, in contrast to the beginning of the problem when legs are the main limb involved.
Typically, Augmentation has been reported with chronic and occasionally acute levodopa treatment (as high as up to 82% of cases) and can be seen within a few months of starting treatment with levodopa. Augmentation also occurs in dopamine agonist use, but the rates are lower and vary between 2% and 35%. It is for this reason that, in the UK, starting treatment with a dopamine agonist and/or levodopa is usually avoided as the standard treatment strategy unless a patient is intolerant to dopamine agonists. Severe Augmentation may lead to a state of utter exhaustion, characterised by sleeplessness, confusion, headaches, severe symptoms of RLS, as well as constant agitation and ‘pill-popping’ - usually a levodopa tablet.
Progress is being made in the understanding of augmentation in RLS and recently a specific clinical scale has been validated which can measure Augmentation severity. Using this, it is likely that in future we will see trials of medications that can effectively treat this problem, a problem which affects the lives of so many patients and their caregivers.
The Rebound phenomenon involves the emergence of RLS symptoms early in the morning or late at night. This often relates to the drug used to treat RLS (the drug's effects last for a short duration) and can be counteracted by using a controlled-release or longer half-life agent at night.
All dopamine agonists are now available in a prolonged release format and one of them can be used continuously by using skin patch – these are effective in counteracting Augmentation and Rebound to some extent. However, in many cases one may have to ensure that the patient comes off the levodopa preparation completely, however painful this may be. Alternative treatment strategies could be used such as non dopamine drugs e.g. Gabapentin, anti-epileptic drugs and powerful painkillers such as Tramadol, or in some cases opiate drugs. These however can only be prescribed with specialist supervision. Sometimes a combined approach is required with input from a specialist psychologist or a psychiatrist to manage the severe anxiety state that occurs with Augmentation.