Amantadine to help focus?

I was wondering if anyone had any experience with the drug Amantadine… my father was placed on this a little over a month ago, and its purpose was to help him focus, because since his aneurysm ruptured (June 2010) he has severely struggled with initiating conversation and making executive decisions (even something as simple as a choice between candy bars). He is VERY easily distracted, which has been a challenge over the past year, and it is extremely difficult for him to focus. He was placed on this medication during his last stay at a rehabilitation hospital so that he could get the best results possible during his therapy-- and he has progressed. Now, however, he is back in a nursing home while we try to make our house wheelchair accessible, and it seems like all the progress we achieved is quickly digressing. Could he have possibly built up an immunity to the drug already? I know this drug is more commonly used to treat Parkinson’s and was originally created as an anti-viral to treat Influenza, but I wanted to reach out and see if anyone else had an experience with Amantadine. Any advice is greatly appreciated!

NO, no experience... I am a subscriber to worst.pills.com...and, also have acessed data off the 'net...

I attempt to promote worstpills.com; membership is $15/year...

Have you called the MD who precribed it last month? Is your dad on any other meds?

Prayers and best wishes...