"i take phentermine 37.5 and a side effect is horrible insomnia. i went almost a solid two weeks before i called my doc to help me find something that would keep me sleeping through the night. she gave me gaba. i take it 30 minutes prior to when i want to get to sleep with my 75mg of topirimate and my spironolatone and within the hour, i&#039;m out. i&#039;m very sensitive to medication also. but i woke up feeling refreshed and not at all zombie-like. i woke up at 2am to give my son a bottle and diaper change with no problem waking up and going back to sleep. i&#039;ve only taken this medicine for four nights but very happy on it so far!! as i said i am very sensitive to medication so finding one that doesn&#039;t make me have lingering side effects is great!"