I use Effexor. While antidepressents, especially SSRI's like Prozac or Zoloft, will block hypnotic response via supressing certain parts of the brain, a person can still reach Alpha, Theta and Delta brain-wave states. If you couldn't, you would not be able to sleep. One thing I was told while on Prozac was to use a sound-light machine to boost the process. I've never followed this advice, as it's a bit expensive, but perhaps you may wish to try it.
One thing that may cost less money, but will cost more time, is learning meditation. While meditation is less "directed" than hypnosis, the ability to control your state can only help increase the power of a paraliminal.
Ultimately, all hypnosis is self hypnosis. Work and plan your hypnotic reprogramming based on this truth.
