Yeah smoking itself can decrease the effects of benzos and caffeine. Other than that, I don't know of any enzyme inhibition in your case.
They like giving klonopin these days. Not entirely sure why, but I think it has better muscle relaxant properties than the others. Valium stays in your system for a way long time, but it really only works for fiveish hours, I thought, whereas klonopin works for more like eight. Xanax is great for working fast against intense anxiety, but it doesn't last long and can cause gnarly rebound anxiety.
Benzos are great for short-term anxiety, but if you can take them as-needed then that is preferable. Otherwise, there are people of whom stay on a constant benzo dose for years or longer. They continue to work, but not as well. Other than that, SSRIs are probably better for long-term. Again, there are people who get a lot of utility from benzos, so not to knock them, they just can lose efficacy and cause a mammoth-level (is that a word?) dependence. Just noting this, not to burn it into the ground or anything.
With valium though the idea is that if you lose your meds or for some other reason can't take them for a few days, then no big sweat. This wouldn't be the case with Xanax!
