Good point!  We only talked about this during the week ourselves.  They are now making headache tablets which are slow release over about an 8-12 hour period.   I guess the problem is that our daughter is currently on 8.75 mg per day over 3 doses (3/4 tablet, 1/2 tablet, 1/2 tablet), and so how could this amount be administered in a single dose?  It would certainly make life a lot easier though.  Hopefully this is something they will work on in the future.