Washington: A new research by University of Guelph scientists has indicated that when doctors give heart drugs to patients, the time of day can make a big difference.
Many doctors prefer to give heart drugs to patients in the morning. But the study revealed that angiotensin-converting enzyme (ACE) inhibitors – commonly given to patients with high blood pressure or after a heart attack or during heart failure – improve heart structure and function when given at sleep time. In fact, when administered during wake time, ACE inhibitors are no more effective than a placebo, the study found.
The research was conducted on mice with high blood pressure.
"Heart drugs are often given to patients in the morning for convenience without considering biological rhythms or time-related risks of adverse effects," said Guelph professor Tami Martino, Department of Biomedical Sciences.
"But if they``re given at bedtime, it``s better," added Martino.
That is because the drug affects a natural hormone involved in heart remodeling. Hormone levels increase at night and cause the heart to enlarge, which damages the organ in cardiac patients, said Martino.
"The sleep-time benefit of giving the ACE inhibitor correlates with the biological rhythm of this hormone," she said.
"By targeting those hormones when they``re highest during sleep, you``re dropping their levels so they``re not doing so much damage," she added.
The study will appear May 17 in the Journal of the American College of Cardiology.