Why medication only works when taken on time

A new study has suggested that one should take the prescribed medication at the right time of day or it might not work as different drugs work at different times on human body clocks.

Scientists for the first time mapped the daily and nightly patterns of gene activity in a dozen organs and tissues around the body and found wide unexpected variations that could affect any drugs targeted at those parts of the body, the Independent reported.

The scientists, who conducted the research on laboratory mice, found that the activity of about half of the genes of the mouse oscillated predictably over a 24-hour schedule. Meanwhile, most of the best-selling prescription drugs are designed to target the proteins controlled by these oscillating genes, and yet have only a relatively short life once inside the body.

The scientists said that while 43 per cent of genes were found to show a 24-hour rhythm, the scientists found 56 of 100 top-selling drugs and 119 out of 250 of the WHO's "essential medicines" work on the products of these oscillating genes.

Taking a drug at a particular time of the day or night might therefore be critical because the medicine may have only a relatively limited time-span to overlap with the activity of a target organ, said Professor John Hogenesch of the University of Pennsylvania.

The study is published in the journal Proceedings of the National Academy of Sciences.