Before starting the search process, it is often a good idea to construct a search strategy. It might be as simple as a few key words or concepts - knowing a few synonyms, variant spellings and related terms can save you time and find you more relevant information. 

Start by determining your keywords, e.g. "drug therapy", "adverse reactions", diabetes

Combine synonyms for each concept with OR - "drug therapy" OR medication OR treatment

Combine the different concepts with AND - "drug therapy" AND "adverse reactions" AND diabetes

When put together, your search strategy may look something like this:

"drug therapy" OR medication OR treatment

AND

"adverse reactions" OR "adverse side effects" OR pharmacovigilance

AND

diabetes OR "diabetes mellitus" OR DM

Using both keywords and subject headings in your search is also recommended. For example, Medline and PubMed use a controlled vocabulary known as MeSH (Medical Subject Headings) to describe the content of available items. This helps maintain consistency and ensures easy accessibility to items on a relevant topic, despite the fact that the author may have used different terms in their own description.

When searching Medline and PubMed it can be beneficial to map your keywords to the MeSH subject headings to improve your search results.

Note that subject headings are not consistent across databases, so you will need to translate your search strategy to 'fit' a database.