Switching a single antihypertensive agent from a morning dose to an evening dose may restore nocturnal BP dips in CKD patients.
Roberto Minutolo, MD, PhD, of the Second University of Naples in Italy, and his colleagues conducted an eight-week trial involving 32 outpatients from a renal clinic. Patients’ renal disease was due to hypertensive nephrosclerosis in 69% of cases, diabetes in 27%, and interstitial disease in 4%; no patient was undergoing dialysis or had received a kidney transplant.
The subjects had a normal daytime ambulatory BP of less than 135/85 mm Hg but they were “nondippers”—their BP did not follow normal circadian rhythms of falling by at least 10% at night.
To counter the nondipping phenomenon and associated cardiovascular risks, study participants were instructed to take their antihypertensive agent in the evening. For those taking two or more such drugs, the agent scheduled to be taken closest to evening became the evening dose. To prevent nighttime awakening, diuretics were the only BP drugs not eligible for evening administration.
After eight weeks, 28 of the 32 patients (87.5%) achieved dipping status, and the night/day ratio of mean BP fell from 0.95 to 0.87, researchers reported in the American Journal of Kidney Disease (2007;50:908-917). This pattern remained apparent when systolic and diastolic pressures were considered separately. Office systolic BP measurements also decreased significantly, from 136 to 131 mm Hg. In addition, urinary protein excretion dropped markedly, particularly among patients whose protein excretion was greater than 300 mg/day.
In an editorial (pp. 901-903), Mahboob Rahman, MD, MS, of the nephrology and hypertension division at Case Western Reserve University and University Hospitals of Cleveland, wrote: “Switching the time of drug administration from morning to evening appears to safely lower nocturnal BP and restore a normal diurnal BP pattern. The next question is whether lowering nocturnal BP can retard the progression of CKD and prevent cardiovascular complications.”