Constipation is a very, very common problem in PD because all muscles more more slowly. Miralax didn't touch mine either. Based on his age, I would check with his doctor first, but common remedies are prune juice, stool softeners, a laxative like Senna, or sometimes a Dulcolax suppository or Fleets enema to get things started. There are stronger products on the shelves as well but they can be quite harsh and cause cramping. Also, he needs to drink tons of water (not caffeinated drinks) every day!
Depression and anxiety occur in about 50% of PD cases and can often predate an official diagnosis. They are very treatable with medication and cognitive-behavioral therapy.
It sounds like your dad needs a new doctor! Instead of a primary care physician or even a plain neurologist, if it is at all possible, he should be evaluated by a Movement Disorders Specialist. You can call the NPF Helpline number on this website for one close to you.
There are often disturbing personality changes associated with PD that can really strain even the steadiest of marriages. Let your mom know that if he's changing, she had done nothing to cause it, it is simply part of the changes going on in his brain.
Finally, you did not mention if they have placed him on any medication. I would pose any question you might have about PD in general or medications specifically to Dr. Okun in the Ask the Doctor Forum. He is always more than happy to explain and advise where he can.
Best wishes to you and your parents. Remind your mom to take good care of herself, especially if she is your father's sole caregiver. You might check their local Division on Aging to see what services might be available to them in their part of Maine.
All you Maineiacs out there, you might be able to offer more insight about your state than I can!
I am not a human being trying to have a spiritual experience; I am a spiritual being having a (sometimes difficult) human experience.
First symptoms: right-hand tremor, constipation and restless arms 1978 (age 25). Depression and anxiety (non-motor symptoms) began in 1989 and worsened through the years. Last inpatient episode June 2013.
Diagnosed December, 2010 by a regular neurologist (age 57). After negative reactions to Requip, Mirapex and selegiline began Sinemet 25/100 3x/day. First MDS visit in Houston in February of 2011 was inconclusive. Second MDS visit at Baylor Fort Worth in May/June 2011 diagnosis changed to Parkinsonism, Sinemet stopped. Third MDS visit in August 2011 in WA State: received a confirmed diagnosis of idiopathic PD which had started on the right side and had now crossed to the left side as well. Restarted on Sinemet 25/100 4x/day. A short trial of Amantadine caused audio hallucinations in September 2011.
Current medications at age 62: Sinemet 25/100 ODT every 2.5 hours while awake (7/day). One Sinemet 25/100 CR between midnight and 4 AM. Trazodone 200 mg at bedtime, Fluvoxamine 300 mg at bedtime. Clonazepam 0.5 mg morning and afternoon, 1 mg at bedtime. Vit D3 2x/day, Calcium Carbonate Susp. 5 cc daily, Baclofen 10 mg 3x/day, Flonase two sprays 2x/day, Calcitonin-Salmon nasal spray once daily (for osteoporosis). Gel eye drops as needed throughout the day, Restasis Eye drops 2x/day, Nighttime eye ointment at bedtime. 02 2L per nasal cannula while asleep. Walker, electric wheelchair, moist and soft or pureed foods and 115 caregiver hours/month keep me sane.
All of the above subject to change based on progression, stress level, and dyskinesia. Whew! I'm glad I finally wrote that all out.