Do we need the drug tag? It has no wiki, and only 6 questions. "Drugs" are not a statistical topic. While it's true that there are statistical components to medical research about the benefits and detriments about drugs, these are parts of larger topics that are subsumed by other tags (statistical hypothesis tests, for instance).
There's clinical-trials that should overlap with "drug" while being more relevant. We have few other relevant tags as well. "Drug" seems broad and not really helpful.
With 'drug' I might potentially think about pharmacology which is about dynamics and kinetics. But all of the 6 question seem to be just some clinical trial, where Tim mentions there's already a tag clinical-trials (currently 392 cases). It seems superfluous to place have an additional tag for just those cases of clinical trials that involve drugs.
The last one might be more of an epidemiological study rather than a clinical trial. It is difficult to say because the question is not very clear.
In addition there is a tag medicine, which has 144 questions. That might also need to be added to clinical-trials, although not every case out of those 144 might be fitting such migration.