Time for your medicine...

Since certain illnesses strike hardest at specific times of day, it seems sensible to time the drugs that treat them so that they reach maximum effectiveness when they are most needed.

Once-daily doses of blood pressure medication can be timed so that they reach maximum concentration during the morning when blood pressure peaks.

Asthma medication therapies can be timed so that they reach maximum effectiveness around 4am when the risk of an attack is highest.

Stiff and painful joints are symptoms of arthritis. People who suffer from rheumatoid arthritis experience most stiffness and pain during the morning, whereas those with osteoarthritis suffer most during the afternoon and evening.

Clearly, it is beneficial if medication taken to relieve these symptoms is timed to deliver maximum relief when the problem is worst. The timing of the dose should reflect the timing of the disease.

Studies have confirmed that the time at which drugs are taken can have an impact on their effectiveness. In 2004, Dr Ramón Hermida of the University of Vigo in Spain carried out research on more than 300 people with high blood pressure. He found that aspirin taken at night significantly lowered blood pressure, while aspirin taken in the morning had little effect.

Dr Francis Levi, at the Hopital Paul Brousse near Paris, is a leading expert in chronotherapy, the application of circadian principles to medical practice.

In a 2001 study, he showed that the effectiveness of certain drugs used to treat pancreatic cancer could be improved, and harmful side effects reduced by careful timing.

Dr Michael Smolensky, an expert in chronotherapy at the University of Texas, estimates that there are about 30 diseases that could be treated more effectively by carefully timed medication.

Chronotherapy is a relatively new branch of medicine, and further research needs to be done. But there is already plenty of evidence that greater understanding of the timing aspects of diseases and the drugs that treat them will bring significant benefits.

Gary Hayden is a freelance writer whose specialisms are: education, science & philosphy, health & wellbeing, travel and short fiction. E-mail: gary@garyhayden.co.uk

This is the last of a three-part series about the circadian clock that controls your sleep cycle, hormone levels and body temperature.

Related stories:

» Part 1: The body's own time keeper

» Part 2: Keeping in sync with nature's rhythms

» Move to your body's bio-rhythm

This article was first published in Mind Your Body, The Straits Times.