PubMed - search for articles. ** Note that this is not a comprehensive search as references may appear in other databases.
COVID-19 Drug Interactions - The Liverpool Drug Interaction Group (based at the University of Liverpool, UK), in collaboration with the University Hospital of Basel (Switzerland) and Radboud UMC (Netherlands), have produced various materials in PDF format to aid the use of experimental agents in the treatment of COVID-19
Royal Pharmaceutical Society - Critical Illness [EMHS & SMHS staff only]
** Most major publishers have made all COVID-19 papers available open access. In general it is advisable to follow the Get it @ E/SMHS button to reach full text to avoid paywalls. Quick ways to connect to paywalled full text - bookmarklets and the LibKey Nomad browser plug-in (note the caveats - these are effective but not 100% effective).