<s>[INST] My father in-law is 65 and had a stroke about 2 years ago. He is currently on high blood pressure medication but tonight he got dizzy and fell.  He was disorientated and we had to help him walk to his room. This is the second time that this has happend in the last 6 months but the first time that he fell. Should we be worried and what actions should we take to prevent this from happening again? [/INST] Hello and Welcome to ‘Ask A Doctor’ service.I have reviewed your query and here is my advice.It seems that he is suffering from Postural hypotension a known side effect of many antihypertensive.Please ask your father in law not to stand up abruptly, but sit before standing up from lying down and visit his general physician, so a substitute antihypertensive can be recommended.Hope I have answered your query. Let me know if I can assist you further.Regards,Dr. Muhammad Adnan Iqbal </s>