Well, its most common use is for anxiety - which is fairly common for people with ADHD. You can read more about it here - http://en.wikipedia.org/wiki/Propranolol
What I don't understand is why your doctor didn't explain this to you. Especially if you are prone to anxiety, the not knowing only makes it worse.
Please note that propranolol is a beta blocker and, in addition to quelling anxiety, will lower blood pressure. Generally speaking this medication is not given if the systolic blood pressure falls below 100.
sometimes Tenex is also used in conjunction with stimulants to help control ADHD symptoms....first I have heard of inderal (brand name for propranolol) being used but makes sense...Always to remember to ask your doctor any questions about your meds and health care...the only stupid questions are the ones not asked....Also beta blockers are also given to help control migraines to regulate fluxs in BP...not because too high but slight changes can trigger migraines... anxiety also triggers these changes...hope this helps!