A mysterious and unpredictable group of side effects from modern medications called idiosyncratic drug reactions (IDRs) likely will persist as a major health care problem unless there is a dramatic increase in research funding, according to a 20-year review of research in the field scheduled.

The review, by Jack Uetrecht at the University of Toronto, defines IDRs as reactions that happen unexpectedly and with no obvious connection to the known effects of a medication’s ingredients or dosage. Although relatively rare, IDRs make an important contribution to the annual burden of death, illness, and increased health care costs from serious adverse drug reactions.

In addition, serious IDRs that appear after a new drug has gone into wide use can force drug companies to withdraw products after R&D investments totaling hundreds of millions of dollars.

Two decades of research have produced significant progress, the report acknowledges. However, medical science still has only a “superficial” understanding of how and why IDRs occur and a growing recognition that the mechanisms behind IDRs may be as complicated as those involved in cancer or diabetes. The review describes a need for increased research funding, with more scientists focusing on IDRs, in order to achieve faster progress.

Article: Idiosyncratic Drug Reactions: Past, Present, and Future, Chemical Research in Toxicology