When to Take Blood Pressure Medication
Updated: Jun 9, 2020
25 APR 2020
For several years, I have been telling patients that if they take medication(s) for high blood pressure (BP) which isn't a diuretic, they should take it at bedtime. My recommendation has been based on previous studies using ambulatory BP monitoring which showed BP during sleep is the best predictor of experiencing complications - such as stroke - as a result of their high BP condition (hypertension).
The higher the BP during sleep, the higher the risk of cardiovascular complications, defined as strokes, heart attacks, heart stents or bypass surgery, heart failure or dying from one or more of these conditions.
A Spanish research group enrolled 18,078 individuals who were provided with 48-hour ambulatory BP monitoring at home(1). The individuals were then tracked and followed up for 5 years.
The results were eye-opening! Even among those with what we usually consider to be a “good” BP, cardiovascular risk doubles for every 5-6mmHg increase in BP during sleep.
As shown in the graph below, compared to individuals with sleeping systolic BP of around 100mmHg, those with a BP of 130mmHg during sleep have 6-fold higher risk of cardiovascular complications.
In a more recent publication(2), the same research group showed the results of comparing individuals taking BP medications at bedtime vs during waking hours. The study enrolled nearly 20,000 individuals taking BP medications and who were followed-up for 6 years.
The research found that systolic BP during waking hours was the same for both groups (129.5 for those taking BP meds during waking hours vs 129.2 mmHg for those taking meds at bedtime).
The 'sleep hours' BP was found to be (only) 2.6% lower for those taking medications at bedtime vs those taking their medications during waking hours (118 vs. 115mmHg).
How about the impact? Well, its staggering. The cardiovascular events for those who took meds at bedtime were nearly halved compared to waking hour dosers!
Cardiovascular death was 56% lower, risk of heart attacks 44% - and stroke 50% - lower, heart failure 42% lower, and the risk for needing to have heart bypass surgery or stenting was 53% lower.
The study also found that the cardiovascular risk reduction afforded by taking BP meds at bedtime was evident in young and old, male and female, those with diabetes, or kidney disease, previous heart problems or stroke, irrespective of daytime or sleep BP.
Asleep blood pressure: significant prognostic marker of vascular risk and therapeutic target for prevention. Hermida RC et al. Eur Heart J 2018. doi.org/10.1093/eurheartj/ehy475
Bedtime hypertension treatment improves cardiovascular risk reduction: the Hygia Chronotherapy Trial. Hermida RC et al. Eur Heaert J 2019. doi:10.1093/eurheartj/ehz754