I was going through my RSS feeds and I found a reference to a database that catalogs incidents of adverse reactions caused by combinations of drugs. The article did not note the location of the database, so I e-mailed Dr. Nicholas Tatonetti and asked him about it. He kindly responded, and the database is available here.
Actually there are two databases. “The Offsides database is a resource of 438,801 off-label — those effects not listed on the FDA’s official drug label — side effects for 1332 drugs and 10,097 adverse events. The average drug label lists 69 ‘on-label’ adverse events…. The Twosides databases is a resource of polypharmacy side effects for pairs of drugs. This database contains 868,221 significant associations between 59,220 pairs of drugs and 1301 adverse events.”