Taking Blood Pressure Medication at Night Enhances Effectiveness

Most doctors recommend their patients take their high blood pressure medication in the morning, but a five-year study has established that taking blood pressure meds at night instead may significantly enhance their effectiveness and reduce the risk of heart attack and stroke. The study of 2156 men and women with high blood pressure was conducted at Spain's University of Vigo. The participants, whose average age was 56, were randomly divided into two treatment groups.  One group took their blood pressure medication at bedtime, while the other took it when they woke up or at breakfast.

Researchers monitored the participants' blood pressure regularly - every 20 and 30 minutes for the first 48 hours of the study, and at least once a year for the rest of the five years.  This frequent testing method, called ambulatory blood-pressure monitoring, provides an accurate picture of blood pressure levels around the clock. The group that took their blood pressure medicine at night experienced only one-third of the cardiac events (such as stroke, heart attack and angina) suffered by the group that took their medication in the morning.  Sixty-two percent of the evening blood pressure meds group controlled their blood pressure over 24 hours, compared to fifty-three percent of the morning group.

Sleeping blood pressure is a chief predictor of cardiovascular risk. Normal blood pressure dips ten to fifteen percent at night.  Those whose blood pressure doesn't dip are more prone to heart attack and stroke.  Thirty-four percent of the bedtime blood pressure medication group were "non-dippers" compared to sixty-two percent of the morning medication group. According to the researchers, taking blood pressure meds before bed prevents the release of chemicals that raise blood pressure during sleep.  Synching high blood pressure drugs to the body's natural circadian rhythms (24-hour cycle) can also lessen unwanted blood pressure medication side effects.  People with secondary conditions such as sleep disorders, type 2 diabetes, heart failure or kidney disease are likely to achieve the most benefit from taking their blood pressure medicine at night.

High blood pressure is usually treated with diuretics, ACE inhibitor drugs, angiotensin II receptor blockers (ARBs), beta blocker drugs or calcium channel blockers. People with stage 2 high blood pressure will likely have to take more than one blood pressure medication. The researchers cautioned against switching from taking your high blood pressure drugs in the morning to taking them at night without checking with your doctor to avoid the risk of nocturnal hypotension (abnormally low blood pressure), which can increase the risk of a stroke.