"i started on phentermine 37.5 august 6th it&#039;s been 13 days, side affects constipation dry mouth.  i have dry mouth any ways due to other medications.  at first i had energy but it&#039;s decreased not sure if it&#039;s the heat. i eat 1300 calories a day a drink loads of water mostly plain ice tea.  so far about 8 pounds loss. started weight 217 now 208 . i usually walk 2 miles but due to the heat i can&#039;t,  i was hoping for a bigger loss but i have constant back pain, which doesn&#039;t help having cage in my back. but i keep trying everyday. i&#039;m not giving up!!!! it&#039;s a start :) my goal is 150..."