hey eric.
that's a good question. one i took the effort (alot) to find out. i wanted to donate blood, so i signed up and filled out the questionnaire without any problems or issues. on top of that, i called them, told them my situation ( i have als and i take riluzole) and had them confirm that i was able to donate blood. so the answer is YES.
HOWEVER, in my case, i still was not able to give blood due to the fact i cannot breathe if i lay flat on my back. i assumed i would be able to sit up and donate, but after being redirected to two other locations looking for seated accommodations, a nurse in charge told me i cannot donate no matter where i go. the american red cross will not allow it because it puts my health in danger.
my advise would be to call first and give specific conditions of your situation before you travel to the location. even though pals on medication are allowed to give blood, there might be issues/circumstances specific to your case which exclude you from donating.
i apologize for the long-winded nature of this reply, but i spent months and three different attempts to be told i couldn't give blood.
very frustrating and disheartening.
i wish you success!