Effects of anti-obesity drugs, phentermine and mahuang, on the behavioral patterns in Sprague-Dawley rat model

According to WHO global estimates from 2008, more than 1.4 billion adults were overweight and among them, over 200 million men and 300 million women were obese. Although the main treatment modalities for overweight and obese individuals remain dieting and physical exercise, the synthetic anti-obesity medications have been increasingly used due to their perceived convenience. Generally, anti-obesity medications are classified as appetite suppressants or fat absorption blockers. In the present study, we examined the adverse side-effects in respect of behavior changes of phentermine and Ephedra sinica (mahuang) that are anti-obesity drugs currently distributed to domestic consumers. Phentermine is mainly classified as an anorexing agent and mahuang a thermogenic agent. Because phentermine and mahuang are considered to display effectiveness through the regulation of nerve system, their potential influences of on behavioral changes were examined employing animal experiments. From the results of experiments testing locomotor activity through the use of treadmill, rota-rod, and open field system, phentermine and mahuang were commonly revealed to induce behavioral changes of rats by reducing a motor ability, an ability to cope with an external stimulus, and a sense of balance or by augmenting wariness or excitement. These adverse effects of phenternime and mahuang in behavioral changes need to be identified in humans and anti-obesity medications such as phentermine and mahuang should be prescribed for only obesity where it is anticipated that the benefits of the treatment outweigh their potential risks.