Health

It's all in the timing

Why are some medicines more effective in the morning than the afternoon? When are we most at risk of heart attacks? David Hughes takes a timely look at chronotherapy

"Time," woody Allen hopefully informs is. "is nature's way of preventing everything from happening at once."

time also turns out to have an unexpectedly important influence on the effects of medicines. And understanding how to synchronise the time we take our medicines with our body's natural rhythms is opening the prospect of more effective , personalised health care, with fewer side-effects.

It's a field known as chronotherapy, which, while still developing science, has already produces some eyebrow raising results.

It turns out that every cell in our body has a natural clock that allows it to anticipare when something is going to happen and make best use of it.

Chronotherapy involves administering medicine when the organ or system it is targeting can gain the maximum benefit. This can be particularly important for older people; as we age, our immune systems become less efficient- yet taking medicine at the right time can help eliminate that disadvantage.

n example is comabatting flu; it's thought that only one in three older people has full protection, despite vaccination. Last year, researchers at the University of Birmingham discovered that flu vaccines given in the morning can be four times as effective as the same vaccine given in the afternoon (Interestingly, preliminary results suggested that the morning shots were best for men, but afternoon ones for women)

Tests have suugested that nearly half of the World Helath Orgnaisation's 250 best selling medicines work differently during the night than during the day- and as the effects of many drugs do not last long in the body, taking them when the bosy can't use them properly is not only wasteful, but gives us less health benefit, and more side effects.

Statins taken for high cholesterol seem most effective when taken at bedtime, when their effect will be greatest to counteract the production of cholesterol in the liver, which peaks after midnight.

Blood Pressure

ACE inhibitors and other drugs to combat high blood pressure may also be most effectively taken at bedtime for people over 55, many of whom do not exhibit the isial 10 to 20 percent nighttime dip in blood pressure usually found in younger age groups.

Non-dipping is a major risk factor for stroke, heart attacj and kidney disease, and taking medication to act during the night significantly reduces the risk.

A five-year Spanish study of 2156 patients published in Chronobiology International in 2011, found a 33 percent drop in heart attacj and stole among those taking blood pressure medicines at night rather than in the morning.

A 2007 American Journal of Kidney Diseases study reported that when 32 'non-dippers' with kidney disease took their drug at bedtime instead of in the morning, 90 percent of them turned into 'dippers' within two months, thier nighttime blook pressure having dropped seven points.

Importantly, the lead author of the Spanish study, Ramon Hermida of the University of Vigo, warms patients not to alter the timing or doses of their medicines before talking to their doctor to avoid dangerously low nightime blood pressure.

Pilot studies have looked at treating hypertension with medications at bedtime, as well as night-release medication for patients with rheumatoid arthritis, whose morning symptoms had been the resault of nighttime inflammation- the hormone melatonin, only secreted during the night, is though to worsen inflamation. Non-steroidal anti-inflammatory drugs, prescribed for osteoarthritis, were twice as effective when taken four to eight hours before the pain peaked, in a 500 patient French study.

Even some cancer treatments are now administered according to chronotherapy. A drug called 5-fluorouracil, used to treat colorectal cancer, tends now to be administered at night, when cancer cells aare most vulnerable. The aim is to deliver treatment when cancer cells are dividing, but normal cells are not.

Body clcok adjustments

Even temorary changes in our body clocks carry increased risk of dsease.

We have more chance of suffering a heart attack for 2 days after the clocks go forward in March, researchers at the Universoty of Alabama discovered, because our body clock is temporarily confused bu reduced sleep.

The same team found that in October the extra hour of sleeo we get when the clocks go back lowers the risk by 10 percent.

And the rhythms of life turn out not only to have a daily fluctuation, but also a seasonal one, according to a pioneering 2015 study from Cambridge University, which looked at 23,000 genes from men and women all over the world.

It found that one in four genes behaved differently according to the season; the good news is, this being the June issue of Choice, that genes associated with suppressing infections seem to be more active in summer.

Personalised Medicine

With the importance of when we take medicine looming increasingly large, recent years have seen efforts to better understand the phenomenon.

Professor John Hogenesch and a team from Pennsylvania University completed a five-year project in 2014 which mapped out the time of day that genes in individual organs are most active. They discovered that genes linked to the lungs reached peak efficiency around lunchtime, for example, while the heart was most active in the morning, and the liver and kidneys after 6pm. The project looked at the 24-hour pattern of thousands of genes, in a bid to improve personalised medicine.

And in March researchers at the Vanderbilt School of Medicine at the University of Tennessee announced they had developed a blood test which monitors the activity of 15 ‘clock genes’, which could help tailor treatments to the individual.

So – who knows? – in a few years, our GP might be telling us not only what to take, but also exactly when to take it – giving a new twist to the adage, “time heals all wounds.”

Always consult your GP before altering the timing or dosage of medicines.

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