It does. It decreases the level of medicine present in your body and makes the medicine less effective

Good morning Mr. I read ur concern : * Two  thinga are important that must be    addressed to you. 1. The above drug don't have any significant      interaction with tobacco . 2. All the 3 things paroxetine, pregablin &     smoking has risk of causing sexual     dysfunction. Since you are young & and have     active sexual life ahead. You should think     about your smoking . -- Medicines you can't stop because they are    important but smoking is not a medicine and    it's not doing any good to ur sexual life,blood    pressure, heart ,brain ,lungs, sleep , apetite &    bowel ,relationship & Money. -- You should think again of stopping smoking     and cutting down one of ur risk of causing     above problems.

It's ok... No issues. If u can reduce it's fine.... Else this much is enough