It did nothing to improve symptoms for my OH. Everyone is different and has a different response to any medication. So, unless it is having severe and unwanted side effects, just give it a try for a while, maybe.
Our neurologist, over many years,has always said, why add another drug that is not having a beneficial effect. Try it and if it isn’t improving things then consider why you are taking it and adding yet another chemical to the mix. Also take expert advice. Mine is just what we experienced and were told.
With respect, GP’s have no idea about Parkinsons as they meet so very few patients with the condition. Take the advice of your neurologist every time, they are the experts, but only IF they are a Parkinsons specialist.