Jane, I have both PD and osteoporosis. I have been taking Fosamax for two and a half years, along with Eldepryl, Mirapex, hormones and Calcium + Vit. D (I do not take Sinemet as yet). In January of this year I had a second bone scan to check on the progression of the osteoporosis. I was pleased that there was no additional bone loss after two years, but there was also no growth in bone density. My mother was severely crippled with both osteoporosis and rheumatoid arthritis and had a lot of spontaneous fractures, especially in her spine. Because I know how painful osteoporosis can be, I don't mind the inconvenience of the Fosamax routine. Fosamax is much more effective if you wait a full hour before drinking, eating or taking meds. I usually shower, get dressed and check email or iron until my hour wait is up. The time goes quickly. The only side effects I had from taking Fosamax were occasional stomach pains for the first week. No problems since then. Good luck to your Mom. Mary Sheehan 60/ diagnosed with PD - 2 1/2 yrs onset of PD symptoms - 14 yrs.