  Background: Network Analysis (NA) is a method that has been used in various
disciplines such as Social sciences and Ecology for decades. So far, NA has not
been used extensively in studies of medication use. Only a handful of papers
have used NA in Drug Prescription Networks (DPN). We provide an introduction to
NA terminology alongside a guide to creating and extracting results from the
medication networks. Objective: To introduce the readers to NA as a tool to
study medication use by demonstrating how to apply different NA measures on 3
generated medication networks. Methods: We used the Norwegian Prescription
Database (NorPD) to create a network that describes the co-medication in
elderly persons in Norway on January 1, 2013. We used the Norwegian Electronic
Prescription Support System (FEST) to create another network of severe
drug-drug interactions (DDIs). Lastly, we created a network combining the two
networks to show the actual use of drugs with severe DDIs. We used these
networks to elucidate how to apply and interpret different network measures in
medication networks. Results: Interactive network graphs are made available
online, Stata and R syntaxes are provided. Various useful network measures for
medication networks were applied such as network topological features,
modularity analysis and centrality measures. Edge lists data used to generate
the networks are openly available for readers in an open data repository to
explore and use. Conclusion: We believe that NA can be a useful tool in
medication use studies. We have provided information and hopefully inspiration
for other researchers to use NA in their own projects. While network analyses
are useful for exploring and discovering structures in medication use studies,
it also has limitations. It can be challenging to interpret and it is not
suitable for hypothesis testing.
