I have been taking 200mg of Amantadine for the last two years with no obvious side effects. However each time I tried to increase to 300mg I got a very strange feeling in my head (probably what Birte called a woolly head).

Recently i have been suffering badly with migraines so with my Neuro's approval I started to reduce my Amantadine to see if it was responsible. Two days after cutting down to 100mg my balance became very poor and my neck practically siezed up and my headaches continued. So having brutally discovered how essential the Amantadine was to me I thought I would give the increase to 300mg another go. So one week after increasing back to
200mg I then upped it to 300mg. This time I have had no strange heads and most of my PD symptoms improved significantly. My symptoms had deteriorated to the point where additional medication was desirable and as I already take 500mg of Madopar (similar Sinemet) I was not keen to increase my Levodopa intake for obvious reasons. My Neuro has prescribed a low dose of Mirapex to add to my existing drugs but after a very bad previous experience with Cabergoline I was not at all keen to try another Agonist.
Like Chasmo I cannot identify any side effects from taking Amantadine now that the strange head sensation has abated, at 300mg, and I am notoriously drug sensitive.

I have read that Amantadine often does not work as effectively for long periods but it is certainly working wonders for me at the moment and with no obvious side effects. But PD is a very complex illness and we all seem to take different drug cocktails even when we are at the same stage of our illness.
So I guess it's a case of careful trial and error for us all.

For the record I later tried reducing my Levodopa intake by one pill a day and my neck siezed up again.

My Neuro has said that I can go up to 400mg of Amantadine a day which I may try as a trade off for reducing my Levodopa intake as I would like to keep dyskinesia at bay for as long as possible.

Sorry that is so long but I hope it helps in some way.

Chris