In Embase, a 'drug' is not necessarily a pharmaceutical substance, the definition is much broader and includes other chemical substances. Here's the definition from the 2018 Embase indexing guide:
"Drug terms are index terms used for all drugs and chemicals: not only therapeutic drugs, but also endogenous compounds, laboratory chemicals, environmental chemicals and environmental toxins. It is important to realize that “drugs terms” as defined in Embase may refer to any chemical entity."
Useful subheadings are applied by the indexers to clinical drugs, including: drug therapy, adverse drug reaction, drug comparison, drug combination, drug interaction. To apply the subheadings in your search, use the Embase Drug search form and choose Drug subheadings.
The indexers also have a list of 47 methods of administering drugs ('routes of drug administration') which are added whenever the method is specified in the literature. To choose a method of drug administration, use the Embase Drug search form and choose Routes:
A disease in Embase includes any kind of health problem from alcoholism to depression. Using the Disease search form you can apply any of the following subheadings:
Pharmacovigilance (PV) involves monitoring the effects of licenced medicines to find and assess any previously unreported side-effects.
The PV Wizard search form takes you through some simple pre-programmed steps:
PV Wizard has a link to EMA's MLM searches. This stands for European Medicines Agency Medical Literature Monitoring. The EMA is currently monitoring approximately 400 substances. You can select one of these and run the same search in Embase that EMA run, to find their evidence-base.
Elsevier provide a useful 5 minute video demonstrating the use of PV Wizard.