Blood Pressure Drugs: Is Timing Key?

Study Shows Switching Treatment From Morning to Night May Help Some Patients

Medically Reviewed by Louise Chang, MD on December 13, 2007
From the WebMD Archives

Dec. 13, 2007 -- Switching the timing of blood pressure medications might help patients with kidney disease avoid life-threatening complications, a new study suggests.

Researchers in Italy report that switching the dose of one blood pressure drug from morning to night helped restore normal nighttime blood pressure patterns in patients with abnormal patterns at night.

In most people, blood pressure normally drops by at least 10% at night, usually between midnight and 3 a.m. The researchers noted that patients with chronic kidney disease who do not experience this normal nocturnal dip have been shown to be at increased risk for kidney failure, heart attack, and stroke, according to the researchers.

With this in mind, researchers from the Second University of Naples tweaked the timing of blood pressure drug delivery to see if they could change nighttime blood pressure patterns.

Normalizing Nighttime Blood Pressure Patterns

The study was small, involving just 32 patients with chronic kidney disease taking more than one blood pressure medication. All of the patients underwent ambulatory 24-hour blood pressure monitoring, and all were confirmed to be nighttime "non-dippers."

When the patients switched just one of their blood pressure drugs from morning to bedtime, 28 experienced normalization of nighttime blood pressure patterns within eight weeks.

Most patients also showed decreases in protein levels in their urine indicative of better kidney function.

The findings appear in the latest issue of the American Journal of Kidney Diseases.

"This is an innovative study, but it was small and the findings need to be duplicated," National Kidney Foundation (NKF) spokesman Leslie Spry, MD, tells WebMD.

The Lincoln, Neb., kidney specialist says as many as 80% of people with chronic kidney disease have abnormal sleep-related blood pressure patterns. By comparison, studies suggest that the phenomenon occurs in about 5% to 10% of whites and 20% of blacks.

Identifying 'Non-Dippers'

Atlanta cardiologist Gina Lundberg, MD, tells WebMD that she has long recommended morning and evening dosing to her patients taking blood pressure drugs.

She says the average patient takes two to three drugs to control blood pressure, but many take five.

"Patients like to take them all at one time for convenience, but they tend to feel better if they spread them out," she says. "And this study showed an actual cardiovascular benefit to doing this."

But she adds that the findings do not mean that all heart patients or even all kidney patients with heart disease would benefit from taking some of their blood pressure medications at night.

Twenty-four-hour blood pressure monitoring is the only way to identify nighttime non-dippers, and Lundberg points out that very few patients are ever monitored this way.

She directs the St. Joseph's Hospital Heart Center for Women and is a spokeswoman for the American Heart Association.

"This study looked at a very specific group of patients, so we can't say that all patients should do this," she says. "But this is intriguing evidence that spreading pills out may have real cardiovascular benefits."

Show Sources

SOURCES: Minutolo, R. American Journal of Kidney Diseases, December 2007; online edition. Roberto Minutolo, MD, PhD, department of nephrology, Second University of Naples, Italy. Gina Lundberg, MD, director, Heart Center for Women, St. Joseph's Hospital, Atlanta; spokeswoman, American Heart Association. Leslie Spry, MD, nephrologist, Lincoln, Neb.; spokesman, National Kidney Foundation.

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