So are you starting with your older medicine that didn't help, or is this a new medicine?

Are your pills round? The best I would do is to cut them in half and try to cut a half in half. but I don't know how small the pill is. Can you ask your doctor to prescribe maybe a 50 or 25 ml? that way you can take one, two or three instead of one big 150? you need to ask your dr for a mood stabilizer along with the anti-depressant.