Can medication side effect change hbp to symptomatic low blood pressure?3 months i use same drug without problems.last few days i feel sleepiness, diz

Yes: if the dose is too high, it can cause hypotension ( low blood pressure); there are instances where a person was not following a proper diet and was obese before but then that person decides to change his/her diet and also loose weight , causing the blood pressure to go low when taking the medication that was given before loosing weight and eating proper diet, also dehydration plus med may cause it

Yes: for many reasons this can occur (change in diet, salt intake, stress level, hepatic induction changes etc.