Dinner on the 27th
Did a little looking on Chuck's Tranq guns. First, they are airguns, which makes them good for covert missions, they aren't as loud as gunpowder.
As to the tranqs, they are frequently used in the wild to tag/rescue/subdue animals. Military and law enforcement rarely use them, especially not in the field, because there is no way to control the dosage. With humans, we vary so much you don't know what is an effective dose on one, and an overdose on the next, and not enough to stop the third.
For that matter, a drug addict might have sufficient tolerance that even if it works, and might not completely, it could take long enough he still has time to do bad things.
On the other hand, we don't have to be that realistic, the Chuck guns really are good tv weapons.