Rotigotine

One of the drugs that is prescribed for me to help manage my Parkinson's disease is Rotigotine. Since the causes of Parkinson's are not well defined, all currently approved Parkinson's medication, including Rotigotine, are limited to treating the symptoms. Rotigotine is a dopamine agonist. Wikipedia describes an agonist as:

a chemical that binds to a receptor and activates the receptor to produce a biological response.

Rotigotine is supplied as transdermal patches, in other words, sticky patches which you stick to your skin so that the drug may be gradually absorbed. Nicotine patches are another type of transdermal patch that you might be more familiar with.

If I have understood it correctly, the Rotigotine molecules have a similar shape to dopamine which means that, once they enter the blood supply, they can bind to the same receptors as dopamine (i.e. the dopamine receptors). I think their shape also means that our brains recognise the Rotigotine molecules as dopamine so it can use them in the same way so that the Rotigotine is effectively mimicking dopamine.

Rotigotine molecule structure

Dopamine molecule structure

Comparing the 2D structure of the two molecules you might well say "they don't look alike at all," to which I would reply "good point." The 2D representations aim to show the constituent components in a simplified form. Due to the myriad ways that molecules can fold, it is much more difficult to predict 3D structure based on its chemical formula. I guess that Rotigotine must fold in such a way that at least one of its surfaces is a good enough likeness for dopamine so that it fits the same receptor. Wikipedia shows that, while Rotigotine is a very good match for some of our dopamine receptors, it performs less well for others.

I apply my patches every morning after brushing my teeth. I say 'every morning' but part of the reason that it is on my mind is that I quite often forget, especially at weekends when my day is less structured. I'm lucky that my symptoms are not so advanced that I can still get away with this for a little while and still go about my daily routine. 

These unintended breaks trigger several effects and offer an interesting glimpse into how the medication affects us. The most obvious and predictable is a worsening of the symptoms that Rotigotine is designed to treat. On Saturday, I was trying to help my daughter lace up some boots that she was trying on and I noticed that the dexterity in my right hand was worse than normal. There are good days and bad days with Parkinson's so I didn't think too much about it.

Later that day, I became incredibly tired. Sleep has become a bit of a paradox. Without medication, I feel tired but I can't seem to sleep. With Rotigotine, I can sleep better but its like my mind won't let me. I find endless, pointless things to do before I go to bed and wake up early with a list of things that I need to do, nagging at me. The Rotigotine keeps me switched on far longer than normal and I push sleep away into a corner. After a day without it, that pile of sleep comes crashing back down on me suddenly and I just have to sleep, whatever else I was supposed to be doing.

As I sleep, I have brightly coloured, vivid dreams that start happily enough until I realise that, although I am in the company of friends or family, they can't see me or hear me, as if I am a ghost. Around this stage, part of me realises that I am dreaming and, if I am not alone, I become aware of noises and voices but my body is so weary that I can't properly emerge from sleep. I try to speak but my words are indecipherable slurs.

Having, eventually come round, there follows a period where I actually feel normal. When I tweeted that I felt like myself for the first time in months, I was interested to find that I'm not alone in having that sensation.

I forgot to put on my Rotigotine patches this morning. My tremor and movement are worse but I feel like myself for the first time in months. #Parkinsons

— Matt Couchman (@Tremr8) November 27, 2021

It felt like I could finally switch off some of the thoughts that had been nagging at me for months.

This, like many of the entries in this blog, is my attempt to understand some of the science concerning Parkinson's disease. Apologies for any inaccuracies, I'm happy to be corrected if you would like to let me know via Twitter or in the comments section at the bottom of the page.