First of all there is no way to determine how safe these diet pills are because they are never tested by the FDA. Most of them are cons and offer no real weight loss. Also, many of them contain herbs and other compounds that may react badly with prescription medications, but they do not tell you that when you buy them. Personally I would steer a wide path away from any OTC or TV advertised weight loss scheme.
If you are really interested in losing weight, you need to consult your doctor to first of all see if you are heathy enough to begin any kind of weight loss program, then have him make suggestions on a diet and exercise program that fits your health condition, body type, and age.
I hope this helps you decide to stay away from this pill, and see your doctor about a weight loss program designed for you. Have a great day.