Under terms of a settlement reached last week, two pharmacists have agreed to give up their licenses in Tennessee.  Michael Griffith is the former pharmacist-in-charge of Xpress Pharmacy of Clay County in Tennessee and will relinquish his license and not practice pharmacy until 2038.   John Polston is the former pharmacist-in-charge of the Dale Hollow Pharmacy, in Celina, Tennessee and agreed to relinquish his pharmacy licenses and not practice pharmacy anywhere in the U.S. until 2040.  Both pharmacists have pleaded guilty to charges of conspiracy to dispense controlled substances and fraud. They are awaiting sentencing.