Hi, Yes, this medication Sifrol (Pramipexole) is a great medication for RLS, but it does work on the dopamine receptors, and I have seen personally some really intense weight gain with this medication. It seems it can slow the metabolism of the body down, not in everyone but certainly in some people and this can have a dramatic effect on weight gain even in people not changing their overall caloric intake. Some of the patients i have had with the weight gain, have had success with overcoming the weight with increasing exercise to offset the slower metabolism and to be honest some patients have had to stop the medication entirely to avoid the added weight. Often times if this the case we can try switching the person to another medication along the same lines such as Ropinirole which works very similarly and is used for RLS. Despite it having a really similar mechanism of action often times switching to different medication can produce less weight gain. Just another thought, even adding Magnesium Oxide 400mg at night can help with the RLS! Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. David J. Girardi, Internal Medicine Specialist