Taking a blood pressure pill at bedtime instead of in the morning
might be healthier for some high-risk people.
New research suggests that simple switch may normalise patterns of
blood pressure in patients at risk from the twin epidemics of heart and
Why? When it comes to blood pressure, you want to be a dipper. In
healthy people, blood pressure dips at night, by 10 to 20 percent.
Scientists do not know why, but suspect the drop gives arteries a
Hypertension fuels heart disease
People with high blood pressure that does not dip at night - the
non-dippers - fare worse than other hypertension sufferers, developing
more serious heart disease. Moreover, heart and kidney disease fuel
each other - and the 26 million Americans with chronic kidney disease
seem most prone to non-dipping. In addition to heart problems, they are
at extra risk of their kidney damage worsening to the point of
Most blood pressure patients need two or three medications. So
Italian researchers performed an easy test: They told 32 non-dippers
with kidney disease to switch one of those drugs from a morning to a
bedtime dose. In two months, nearly 90 percent of these high-risk
patients had turned into dippers. Their night time blood pressure
dropped an average of seven points, without side effects or increase in
daytime blood pressure.
Better, a key sign of kidney function improved significantly, too,
Dr Roberto Minutolo of the Second University of Naples reports this
month in the American Journal of Kidney Diseases.
It's the latest research in the field of chronotherapy: How our
bodies' internal rhythms make certain diseases worse at certain times
of the day, and in turn affect how to time treatments.
How big a problem is non-dipping?
"I think it's huge," says Hopkins' Dr Lawrence Appel. "This is our
best lead" into why black Americans with kidney disease, in particular,
tend to worsen despite treatment.
Appel found 80 percent of black kidney patients in a recent study
were non-dippers. Most startling, 40 percent had night time blood
pressure that was even higher than daytime levels.
Two-thirds of chronic kidney disease patients, and at least 10
percent of the general population, are estimated to be non-dippers,
says Dr Joseph Vassalotti of the National Kidney Foundation. One
theory is that their bodies have trouble excreting salt.
Yet few patients have ever heard of the problem - and few doctors
know who is affected. Most people get their blood pressure checked only
during the day. A 24-hour blood pressure monitor can tell but is rarely
used, partly because insurance seldom pays for the extra visit to
download and diagnose the readings.
Pills wear off by night time
And most patients who take several once-a-day pills swallow them all
in the morning, meaning they all start wearing off around the same
time, says Dr Gina Lundberg of St. Joseph's Hospital in Atlanta.
"It does make good sense to take some in the morning and some in the
evening," says Lundberg, a spokeswoman for the American Heart
Everyone has an internal clock, determined by genes, that affects
health. Many of these biological rhythms are circadian, meaning they
fluctuate on a 24-hour cycle.
Consider how that can affect the timing of treatments. Some older
"statin" pills fight cholesterol best if taken at bedtime; they target
a liver enzyme that's most active at night. Asthma attacks are more
frequent at night, and the stomach secretes more heartburn-causing acid
at night, affecting some patients' dosing requirements. Researchers
even are studying how to better time certain cancer chemotherapies and
The best-known example: Blood pressure jumps in the early morning
hours, as the awakening body produces more stress hormones. That is
also why heart attacks and strokes are most common in the morning.
The night time dipping problem has gotten far less attention. The new
Italian study marks an important advance, says Dr Mahboob Rahman of
the University Hospitals of Cleveland.
"We know now that you can change medication timing and lower blood
pressure at night," he explains.
That does not mean everyone should switch to bedtime dosing. Morning
may be best for people on just one drug, and no one yet knows if the
switch truly gives non-dippers better overall health. "That's the
million-dollar question," Rahman cautions. – (Lauran Neergaard/Sapa)
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