Phentermine diet pills are prescription diet pills that are marketed under such names as Obermine, Obenix, Oby-Trim, Fastin, Anoxine-AM, Lonamin, Obephen, Obestin-30, Phentrol and by Adipex-P. Phentermine diet pills have been in use since 1959 and are FDA approved to help with short term weight loss in people who are severely obese. Phentermine varies the serotonin levels and releases a chemical called Adrenaline which may causse such side effects as high blood pressure and insomnia. The other side effects that are caused by Phentermine are dizziness, reduction in appetite, loss of sexual desires and restlessness. Phentermine is very addictive in nature and it is very difficult to quit as it results in depression and in lethargy. Used in combination with a good healthy diet and exercise regimen, and under the care of a physician, Phentermine diet pills can kick start your weight loss goals. You may need to take a break from taking the phentermine diet pills after a few weeks as your body becomes accustomed to them and, after a while, your weight loss will stop. Taking a break for a few weeks will help you once again to start to lose weight. Phentermine diet pills should only be used for short periods and only after a complete physical from your doctor.  As with other prescription medication, they can be dangerous if you have other health issues.