A new approach to treating restless leg syndrome and periodic leg movement disorder

Last year, I noticed a worsening of my restless leg syndrome (RLS) and my periodic limb movement disorder (PLMD) symptoms. For years, I only suffered from restless legs, and maintaining my serum ferritin levels above 50 with occasional iron supplements always solved the issue. Then, I suffered a decline in the quality of my sleep and visited my own lab here in New Mexico, where we discovered scattered independent leg movements, known as PLMD. Before taking the leap to test the standard, established evidence-based drugs, I pursued two other pathways. First, I bumped up my iron levels closer to 100 as one scientific publication suggested this step might further decrease RLS/PLMD symptoms. The second approach was to bump up my Vitamin D supplements as two recent publications have suggested a connection between RLS/PLMD and low levels. Neither of these efforts made any difference in the quality of my sleep.

Before asking my primary physician to prescribe a standard medication (e.g. Mirapex, Requip, Neurontin), I elected to investigate alternative medicine literature for anything newly researched. I’ve scoured these resources frequently over the past several years hoping to find something for those patients unwilling or uninterested in attempting prescription drugs. As you probably know, you can find tons of advertisements and almost no research on alternative medicine products; and as RLS/PLMD are so common you will see lots of “endorsements” for allegedly successful remedies. Indeed, I know a fair number of patients who have tried several alternative medicine approaches, but rarely do we see documented decreases of leg jerks in the sleep lab. Moreover, rarely do patients inform us of great benefits.

In my search near the end of 2017 I found this research on L-Tyrosine and RLS. A summary of this research proposal reads as follows:

Tyrosine is a non-essential amino acid that is the precursor of the neurotransmitter, dopamine. Tyrosine is converted into Levodihydrophenylalanine (L-Dopa) and L-Dopa is subsequently and avidly converted into dopamine. It is well known that dopamine deficiency leads to the manifestations of restless legs syndrome (RLS). Studies have shown dopamine agonists and L-dopa to be effective in controlling symptoms. No studies to date have been done to determine the role of Tyrosine in RLS. This open-label pilot study aims to determine the efficacy and tolerability of tyrosine in RLS, as current agents have limitations in treating RLS in addition to adding another possible agent to the investigators arsenal of treating RLS that may be more cost efficient. In this pilot study, the dose of Tyrosine will be escalated from 750 mg once daily by mouth (PO) up to 3000 mg once daily PO, as tolerated, in increments of 750 mg every week in patients who meet the inclusion criteria for RLS. Patients' symptoms will be monitored on a weekly basis for six weeks.

The most remarkable finding on the website is the absence of any published results. The protocol was arranged by an organization named Seton Healthcare Family in Austin, Texas. I have attempted to contact this organization to find out whether the study was ever conducted and whether any results are available. To date, I have spoken with a sleep doctor in this organization who had no knowledge of the research, but he speculated there might be a neurology group involved in the work. He indicated if he found out some new information, he would contact me.

In the protocol, you will notice they mention open-label trial, which means there is no control group. In particular, there is no placebo used in this kind of study. Instead, all patients enrolled received the same protocol of 750 mg/daily of L-Tyrosine for one week followed by weekly increases to 1500 mg, then 2250 mg, and then 3000 mg. The last dosage of 3000 mg would be in use by the patients from the 4th through the 6th week, at which point the experiment would conclude.

The study was designed to assess RLS treatment without mention of PLMD.  Nonetheless, those with RLS usually suffer from PLMD, and whatever works for RLS often works for PLMD as well. Many of the original drugs for these conditions are related to the pharmacology of the neurotransmitter dopamine, and the original agent (Sinemet) was a combination of two drugs called carbidopa/levodopa. For more than a decade, the drugs Mirapex (pramipexole) and Requip (ropinirole) have been mainstays in the fields of sleep, psychiatry, and even primary care for the treatment of RLS/PLMD.

With this backdrop, and as noted in the protocol, L-Tyrosine might be expected to work by enhancing availability of the precursors to dopamine and thus produce more dopamine. Not being a pharmacology expert, let me just say this explanation seems the most practical and coincides with the one offered in the protocol, but this theory does not preclude the possibility of other explanations for how Tyrosine might treatment leg movements or perhaps promote better sleep quality. In fact, if you explore the alternative medicine endorsements just using internet searches you will find a great deal of paradoxical information attesting that L-Tyrosine is beneficial for completely different purposes. For example, some use it for RLS/PLMD or for sleeping better, whereas others report using it in the daytime as a stimulant to decrease sleepiness and increase concentration. Others report L-Tyrosine has mood-altering properties such that it might decrease anxiety and depression. This bewildering array of effects might suggest it is a very powerful supplement, but it also might indicate contradictory evidence suggesting it doesn’t really work for anything.

Not knowing any way to judge the accuracy of these testimonials while holding a high level of suspicion for things that are advertised - but not thoroughly backed up by research, I elected to take the plunge and try L-Tyrosine for my objectively diagnosed, untreated independent leg jerks. Let me reiterate that my motivation for starting the supplement was generated by worsening of the quality of my sleep, which consistently led to degrees of daytime sleepiness and fatigue I had not experienced in years. Periodically, I have suffered minor bouts of sleepiness that often responded to changes in my masks or slight changes in my ASVAuto pressure settings. Or, in some cases, a cup of hot cocoa or green tea was sufficient to address the problem. But, the sleepiness I was now experiencing as much as two or three days in the week was sufficient to induce napping during the daytime. This degree of daytime hypersomnolence had been relatively rare for more than a decade.

The first night I selected the low dosage of L-Tyrosine 500 mg, and I can honestly report the very next morning I knew I had slept better with more dreaming that night and feeling more refreshed that morning. Given my scientific bent, I proceeded to alternate a few nights with 500 mg of L-Tyrosine and then a few nights without for about two weeks. At the end of this initial experiment, I was persuaded the benefits were positive and very noticeable. So, I went to every night use of 500 mg for the next two months, and among all the findings the most noticeable were two things. First and foremost, during the daytime, the sleepiness and napping behavior were virtually eliminated. However, the second and somewhat odd finding was the excruciating sense of deeper and more prolonged sleep inertia in the morning.  There were episodes where I would awaken in the morning and would need to remain in bed for almost an hour, probably going in and out of various stages of sleep including REM as I recall dream activity. In this first phase of use, I noticed if I got out of bed ‘too early,’ I felt the need to walk more slowly, and if I had work at the computer, my typing speed was slower and clumsier. Still, the remainder of the day brought an overall level of productivity much higher in comparison to when I was suffering from the napping behavior and fighting drowsiness.

Early this year, having used the 500 mg dosage for about 2 months, I noticed a drop off in the effects and elected to increase the dosage to 1000 mg. I immediately noticed the same levels of improvement, that is decreased napping behavior and fighting off drowsiness, both of which lasted another two months, then I noticed another drop off. In March, the dosage was increased to 1500 mg and since then I have also used 2000 mg occasionally. However, recently, I was persuaded that the effects of the larger dosages were not necessarily any better than the 1000 mg, so for the past couple weeks I only use two 500 mg pills near bedtime.

Just like many of the prescription pills advertised for RLS/PLMD, there is no sedating effect of L-Tryosine at bedtime. Using the supplement at bedtime, 30 minutes before bedtime or even 2 hours before bedtime has had no impact on when I feel sleepy prior to lights out. And, since my RLS has remained under good control with iron supplements, my theory is that L-Tyrosine is treating my PLMD only. However, given the discussion of sleep inertia in the morning, I have experimented with taking the supplements more than 30 minutes before bedtime. I do think this timing issue has some impact on the duration and depth of the sleep inertia, but I have yet to sort out a perfect system to decrease these sensations. Then again, at this point, I am not overly concerned as it is clear some portion of this inertia represents actual sleep time, almost always with my ASVAuto PAP in place, so presumably high-quality sleep. On a few occasions without the PAP, my sense is this additional slumber remains at higher quality, probably due to the 'momentum' effect of having used PAP for several hours before this short non-PAP period.

Regarding some of our other like-minded individuals, you may know that many patients throughout virtually all healthcare systems show strong reluctance to the use of medications and instead frequently pursue alternative medicine pathways. I was intricately involved in several alternative medicine methods and institutions for almost a decade before entering medical school, so I am very aware of how so many people look for non-allopathic or natural remedies. At our center, we see many such folks who absolutely refuse to consider prescription pharmaceuticals. I believe that some of this reluctance comes from a proportion of RLS/PLMD patients who do not believe their legs are moving during the night. In some ways, this perspective is similar to people who do not believe they suffer from any breathing events at night and therefore question the need to attempt PAP therapy. Leg jerks of course are more difficult to define as an independent disorder until breathing has been normalized with PAP therapy or some other modality. So, in the clinical setting we might be at a disadvantage with some patients who were previously reluctant to use PAP, yet now must consider adding a medication to treat their leg jerks to optimize results. In most of these cases, patients are not gaining a superlative response to PAP, largely due to the untreated PLMD. Some will have tried prescription medications and suffered numerous side-effects. Others completely reject the notion of using prescription drugs.

Some anecdotal evidence has emerged from these types of patients. Among such individuals whom informed about L-Tyrosine use, we are aware of roughly 10 patients who attempted or are attempting regular use of the supplement. For a couple patients, there was no benefit, but the remainder reported similar improvements as described myself. A common report is “I am definitely sleeping deeper.” As we retain a certain cautionary approach to this atypical recommendation for these patients, we present them with the following information inserted into their most recent sleep study reports and discuss the ideas before they make their decision to start the supplement:

Regarding leg jerks, because the patient has tried other prescription medications and may no longer be interested in pursuing such treatments, the patient may wish to consider L-Tyrosine supplements, starting at 500 mg at bedtime and increasing over several weeks to the 1000 to 1500 mg range. There is no authoritative research on the use of this supplement, but there are several references to it in the alternative medicine community, and we know of a few patients who are reporting benefits from its use. Unfortunately, information on any side-effects related to L-Tyrosine are not well established, so any patients using the supplement must use their own judgment in initiating this medication and is advised to monitor for any other changes in mental or physical health. Two side-effects that may be relevant include: (1) patients with thyroid disease may need to check their thyroid function tests when using Tyrosine; and (2) some people report increased sleep inertia when awakening in the morning. Speculatively, as Tyrosine is a precursor to dopamine, the question might arise whether this amino acid supplement would produce side-effects similar to Mirapex or Requip, both dopamine agonists, including unexpected compulsive behaviors, potentially related to shopping, gambling and sexual activity. If the supplement is effective in decreasing RLS/PLMD symptoms, we anticipate the patient would note a deeper and more consolidated sleep when used in combination with PAP therapy.

Of course, the fact that L-Tyrosine is a supplement means the chances of finding high quality research that designates the frequency of side-effects would be very low. There is also the question of tolerance or eventual diminishing returns from the supplement just like any other drug. Again, it may be difficult to find research on these topics.

In summing up, we certainly can’t declare that L-Tyrosine is safe or that it provides benefits, but it appears at this point to be a supplement that might indeed provide benefits and potentially may have an excellent safety profile. When would we find out the definitive answers to these questions? Arguably ‘never’ might be the right answer because who would choose to fund this research? I already approached one of the leading manufactures of OTC vitamins, minerals and supplements, and they politely declined, indicating they would not fund a 3rd-party researcher. From a business perspective, however, we can see their rationale, because anyone who conducts the research and proves L-Tyrosine works well in RLS/PLMD has just opened a new revenue stream for every other company that makes the supplement. A quick internet glance suggests no less than 10 major manufacturers are making L-Tyrosine currently.

Therefore, the only alternative in an alternative medicine perspective is the trial and error approach, otherwise known as the “N of 1” experiment in which you experiment on yourself. That’s the approach I have taken for myself and going forward there are two more steps I am hoping to pursue later this year. First, I want to go back into the sleep lab after maintaining a stable dose of L-Tyrosine for a several months to determine whether there is a decrease in the frequency of independent leg jerks. Second, I want to taper off or discontinue L-Tyrosine and then try one of the dopaminergic medications such as Mirapex or Requip to see whether or not the response is identical to what I have achieved with the supplement. These steps would provide me with a lot more confidence in trying to understand how L-Tyrosine might be working and whether or not it is truly working.

In the meantime, caveat emptor remains in play, but so many people refuse to attempt prescription medications for RLS/PLMD, perhaps L-Tyrosine would be something a person would try on a temporary basis to determine if relief would be forthcoming. If so, the patient would then be convinced that the leg jerks clearly need to be treated, and from that point going forward the patient will at minimum recognize that RLS/PLMD is something they need to get a leg up on in their treatment of all their sleep disorders.


Barry Krakow MD

Author

Dr Krakow’s 27 years of sleep research have focused on the complex relationship between physiological and psychological sleep disorders. Dr Krakow currently operates private sleep medical center, Maimonides Sleep Arts & Sciences, Ltd., and serves as Classic SleepCare’s paid Medical Director.



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