Not in the DEA, the Administrator's point of view is that they too valuable to risk in the field. There's laboratory and non-LE jobs that pharmacists occupy. In Homeland Security, yes, but not as law enforcement, but as Intelligence. There's about twenty to thirty pharmacists at any given time there working on various Surveillance initiatives that are being cooked up.
If LE in these fields is your goal, the more likely pathway is post-military enlistment or started in the police to begin with. For technical support, there are jobs out there, but they're not that straightforward to find. There's a negative perception of someone who obviously wants to work in LE that is from a technical field for the same reason that the government tries not to hire people who openly want to be weapon scientists as it's the wrong psychological profile for the sort of work required.