"i started phentermine 05/13, by 07/13 the medication felt as if it had quit working. i become &quot;immune&quot; to medication. example, i have high blood pressure &amp; diabetes. i have to change my medication and insulin every 3 months because they quit working. i can eventually go back to the same meds, but only after they&#039;ve been switched up a bit first. 
my doctor upped my dosage to x2 a day. i got the script 09/01/13 &amp; joined the gym that same day. i&#039;ll take the phentermine for 3 weeks, then come off for 10 days. start again for 3 weeks. i work out 5 days a week, for 1 1/2 hours. on 03/07/14 i had dropped 56lbs. no where near what i wanted. that same day, i started the topamax. i&#039;ve not weighed yet but i feel a difference. no major side effects."