Will drowsiness from combining Prozac & Zyprexa go away with usage?

Hi, fiamm! Drowsiness/Sleepiness is not an uncommon side effect when starting some psych meds especially the antidepressants like your Prozac. For most people these effects subside over a matter of just a few days to a week or so as your metabolism adjusts to the drug.
Have you tried taking your meds at night so you can just sleep through the drowsiness? It's okay to take them morning or evening as long as you take them about the same time each day.
Feel free to come here anytime with any questions or concerns you may have ~ there are quite a few Bipolars here so you are not alone.
Best regards, Wildcat