"i have been on meridia 10 mg for approximately a week and a half. the only side effect that i have had is jittery sleep (i.e. i wake up a few times throughout the night and am very alert but can go right back to sleep - its odd! i am usually a very heavy sleeper) but this is no deal-breaker...meridia has already been extremely effective - i have lost 6 pounds in a week and a half. i am about 40 lbs overweight so i still have a long way to go but it is such a relief that this is getting the ball rolling - the weight loss finally feels surmountable. other reviewers are certainly correct - you do have to put in effort on this medication - it isn&#039;t a magic pill. i have stuck religiously to a 1200 cal diet &amp; cardio for 30 min 5 days/week."