"i have been on pristiq for a few years now at different dosages:  
50mg - positives: loss of appetite, weight loss and feeling great. negatives:  your body gets used to the medicine until it seemingly no longer works.  the side effects of loss of appetite, sleep patterns etc. do stop after about 3 weeks.
100mg - feel good, appetite normal. negatives:  you will feel drowsy to exhausted.  again my body seems to get immune to the dosage.
200mg - postive:  feel good and normal energy levels. negative:  major weight gain, constipation and you feel the cold/hot flushes. these side effects don&#039;t wear of with time at this dosage."