Switching the dose of one blood pressure medicine from morning to night helps restore a healthy rhythm to blood pressure, which protects against kidney and cardiovascular problems, according to a new study appearing in the December issue of the American Journal of Kidney Diseases, the official publication of the National Kidney Foundation.
In healthy individuals, blood pressure drops by at least 10% at night. Research shows that people whose blood pressure does not dip while sleeping are at greater risk of cardiovascular problems. Among the 26 million Americans living with chronic kidney disease (CKD), those whose blood pressure does not dip at night have a higher chance of developing kidney failure, a life-threatening condition that requires dialysis or a kidney transplant.
In the current study, researchers tested the intervention in people with CKD whose blood pressure did not drop by at least 10% at night. They found that switching the dose of one blood pressure medication from morning to bedtime restored a normal blood pressure fluctuation in nearly 9 out of 10 people. Importantly, after the switch, patients also excreted less protein in their urine, a sign that their kidneys were functioning better.
According to study corresponding author, Dr. Roberto Minutolo of the Second University of Naples, Italy, "We planned this study on the basis of the common observation that antihypertensive drugs work best in the first hours after they are taken. We verified that in patients with chronic kidney disease, shifting a drug from morning to evening ensures a greater antihypertensive effect during the night. This approach is simple but very important because it limits the phenomenon of 'non dipping' blood pressure at night that is a well-defined risk factor for progression of kidney disease and development of cardiovascular complications. "
"This finding shows that a simple act - taking a pill at night, instead of first thing in the morning - can have an important effect on the health of CKD patients, who are particularly vulnerable to cardiovascular and kidney complications," says Allan Collins, MD, President of the National Kidney Foundation.
In people with CKD, the kidneys are less able to perform vital functions that help maintain overall health, including filtering wastes and excess fluids from the blood.
According to data released this month, the prevalence of CKD rose by 30% between 1994 and 2004, now affecting 26 million American adults - most of whom are completely unaware of their condition. People at increased risk of CKD include those with diabetes, high blood pressure, cardiovascular disease and a family history of kidney failure. Minority groups and older adults are also at increased risk.
During the current study, researchers followed 32 patients with CKD whose blood pressure did not dip overnight. Most patients were taking more than one blood pressure medication, and the researchers asked them to take one medicine at night instead of first thing in the morning. Eight weeks later, they found that 28 out of 32 people showed a normal dipping in their nighttime blood pressure. Importantly, the amount of protein in patients' urine also decreased significantly following the medication switch, which research has associated with better long-term kidney and cardiovascular health.
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