My husband has now tried Sinemet on 2 different occasions and each time he complains of constipation & therefore stops taking it. His symptoms are getting worse - very depressed, starting to lose mobility, occasional voice problems , occasional swallowing problems and increasing depression. Is there a quick (?) remedy for constipation ? He uses lactulose atm, to no avail. He says he feels like he is slowly dying. 
Ive used movicol for constipation. It can be gotten either as sachets mixed with water or liquid. (All liquids in general can be thickened with thickener.) I think the liquid version doesnt taste as gross. I don’t need movicol anymore. When I did use it I think ‘normal’ is 1 a day. I alternated between 3 and 4 a day. Though lactulose and movicol seem to be from the same ‘family’.
Hi mckenzie, my husband takes Sinemet and has done for almost 8 years. He’s always suffered from constipation, even well before he was diagnosed with PD. He takes Cosmocol in the morning, followed by glass of prune juice. I also give him golden flax seeds on his breakfast cereal as suggested by his PD nurse. He was also prescribed bisocodyl to be taken at night. I think the problem of constipation in PD can also be caused by the disease itself as the muscles that help motility of the bowel can become slowed down and rigid. Maybe you could discuss this problem with your PD nurse before stopping his Sinemet as we’ve found it’s a very useful drug which has helped my husband control symptoms very effectively over the years. Hope you can get this distressing condition resolved and under control so he can resume with his Sinemet. Best wishes, Jean.
Jean, Thank you so much for your reply and advice. I will definitely try what you’ve recommended. My husband was diagnosed 8 months ago but is not taking Sinemet regularly and seems to be deteriorating quickly. Atm, he has Covid and can’t even walk or feed himself - this has happened almost overnight.
I find that eating 3 or 4 dried prunes every day does the trick.
Hello Jean1
My husband with Parkinsons has developed constipation a long the way (diagnosed with Parkinsons 12 years ago) he takes lactulose and splits the doses through the day. He uses 2 sachets but takes them separately at different times if the day. I don’t know if sinimet causes constipation could you husband be thinking its the sinimet causing the problem when its just Parkinsons.
The sinimet made a tremendous difference/improvement in my husband when he was prescribed it, was like having him back to his old self so much better. As the old expression goes - could he be ‘cutting his nose to spite his face’ not helping himself atall.
Encourage him to go with the sinimet again and include some constipation remedies, stick with it for a while yo give it a chance.
I’d take him (once Over Covid) to GP too for help with depression (also a Parkinsons symptom)
Good luck snd I hope he gets over Covid quickly. Best Wishes Jane
Hello plus1, I think this reply may be for mckenzie…
Regards, Jean1