When Should You Take Blood Pressure Medication?

When you get a prescription for high blood pressure medication, your healthcare provider usually tells you how to take it: by mouth, once (or twice) a day. But if you take it once a day, when should you take it?

Traditionally, physicians have recommended people take high blood pressure medication in the morning, as part of their get-up-and-go routine. But some scientific evidence shows it may be better to take it at night. 

So what should you do? Let’s take a look at what the science says (and what remains a mystery). 

Does blood pressure change throughout the day?

Blood pressure changes throughout the day to meet the body’s needs. In most people, blood pressure levels follow the circadian rhythm — the 24-hour cycle that regulates our sleep/wake pattern. 

Our circadian rhythm is regulated by hormones, like adrenaline and noradrenaline. These hormones increase blood pressure first thing in the morning, otherwise known as the “morning surge.” Another hormone involved in circadian rhythm is melatonin, which lowers blood pressure at night. 

What time of the day is blood pressure highest?

For most people, blood pressure usually starts to rise around the time you wake up in the morning. It surges as you start your morning routine and peaks sometime around midday. In the evening, blood pressure starts to lower. In most people, nighttime blood pressure is usually 10% to 20% lower than daytime blood pressure.

Abnormal blood pressure patterns

Not everyone has the typical rise in blood pressure during the day and dip at night. For example, some people have higher blood pressure when they’re asleep than when they’re awake. 

Examples of such atypical or abnormal blood pressure patterns include:

• Higher blood pressure at night than during the day (“reverse dippers”)

• Blood pressure that doesn’t drop overnight (“nondippers”)

• Very low blood pressure at night (“extreme dippers”)

People with abnormal blood pressure patterns have a higher risk of heart disease. That’s especially true for those with high blood pressure at night. They’re also more likely to have:

• High blood pressure that’s difficult to treat

• Obstructive sleep apnea

• Diabetes

• Thyroid disease

• Overweight or obesity

• Unhealthy lifestyle habits, such as cigarette smoking

When researchers found that some people have atypical blood pressure patterns, a group of experts started to question if traditional morning dosing of blood pressure medication was right for everyone. They especially wondered about people who had higher blood pressure at night. Before we get into the science on that, let’s go over some blood pressure medication basics. 

How long does it take blood pressure medication to work?

The time it takes for blood pressure medication to work depends on the medication and the dose. Your age, weight, and any other medications you take also play a role. 

Some medications — like clonidine, captopril, labetalol, and nifedipine — start to work quite rapidly, within minutes. Others — like amlodipine and hydrochlorothiazide — can take hours before they have an effect. 

How long does a dose of blood pressure medication last?

Another thing to consider when taking blood pressure medications is how long the effects of the medication last. Again, it depends on what blood pressure medications you take. But the most common blood pressure medications work for a full 24 hours and are taken once a day. 

Examples of common blood pressure medications designed to last 24 hours include:

• ACE inhibitors (lisinopril and benazepril)

• Angiotensin II receptor blockers (losartan and candesartan)

• Calcium channel blockers (amlodipine and nifedipine ER)

• Diuretics (hydrochlorothiazide and chlorthalidone)

But these medications don’t work the same for everyone. Some people taking these once-a-day medications find that their blood pressure varies throughout the day or creeps up toward the end of the 24 hours. If this is happening to you, touch base with your healthcare team. You may need to take a higher dose, change your medication, or take it at a different time.

What does the science say about taking blood pressure medication at night vs. the morning? 

We now know most people have higher blood pressure in the daytime and blood pressure medications start to work within a few hours. And the effect usually lasts a full 24 hours. So does this mean most people should take their blood pressure medications in the morning? 

Let’s review what the medical guidelines say. Medical guidelines, or clinical practice guidelines, summarize the current evidence on a topic. At the moment, there are no formal guidelines for when people should take blood pressure medication.

This means the evidence is not strong enough for experts in the field to decide the “right” time for people to take blood pressure medications. So guideline experts have left the decision to individuals and their healthcare providers.

But some scientists feel strongly that timing matters for high blood pressure treatment. They call this “chronotherapy.” Most of these experts say that it’s better for heart and vascular health to take blood pressure medication at night instead of the morning.

So what’s the right answer? Let’s take a deep dive into the data on this highly debated topic.

Evidence for taking blood pressure medication at night

Experts in chronotherapy think high blood pressure during sleep is much more common than previously believed. And studies show that people who have higher blood pressure at night have a higher risk of developing cardiovascular problems — and a higher risk of death from these problems. Because of this, they think people should take blood pressure medication at night.

In general, supporters of this base their opinion on the findings of two trials:

1. The MAPEC study recruited over 2,000 people and randomly assigned them to 2 groups. One group took their blood pressure medication in the morning and the other took it before bedtime. The study followed participants for an average of 5.6 years. The results showed that the nighttime group had significantly lower blood pressure, both during sleep and the day. The nighttime group also had lower risk of cardiovascular problems and death.

2. The Hygia Chronotherapy Trial — led by the same researcher as the MAPEC study — enrolled over 19,000 participants at over 40 centers in Spain. Again, the trial divided participants into two groups. One group took their blood pressure medication at night, and the other took it in the morning. The trial monitored blood pressure for an average of 6 years. The researchers reported a large drop in risk of cardiovascular problems in the nighttime group.

The improvement in heart-related risk in this second trial was so large (45%) the study gained international media attention. But both the MAPEC and Hygia Chronotherapy trials have faced criticism and doubt within the medical community. Many blood pressure experts question the design of the studies and the reporting methods of the teams.

The journal that published the Hygia Trial formally questioned its results. The blood pressure measurements between the morning and night groups didn’t seem large enough to explain the significant difference in long-term health outcomes between the two groups. 

In summary, there’s some evidence that taking blood pressure medication at night may be slightly better for lowering 24-hour blood pressure. But more research is needed to see if nighttime dosing translates into better long-term health outcomes.

Evidence for taking blood pressure medication in the morning

There are some good reasons to take blood pressure medications in the morning. 

First, lowering blood pressure too much at night can be risky — especially for older adults:

• Having very low blood pressure at night, then a morning surge in blood pressure, can actually raise cardiovascular risk, compared with those who have high blood pressure at night.

• Low blood pressure at night has been linked to a greater risk of stroke in older people. 

• For older adults who have low blood pressure when standing, there’s a link with frailty and falls — a particular risk at night.

Studies have also linked blood pressure that drops too low at night to an increased risk of not enough blood and oxygen to the heart muscle in people who have coronary artery disease (CAD). So for older adults and people with CAD, it may be safer to take blood pressure medication in the morning. 

When researchers directly compared morning versus night blood pressure medication dosing, studies have shown benefits to morning dosing. One study tested the 24-hour blood pressure medication perindopril at 9AM versus 9PM. It found that dosing the medication in the morning resulted in lower blood pressure throughout the day. 

In summary, many experts argue that there’s simply not enough good evidence yet for a person to switch their blood pressure medications from morning to nighttime. They advise that providers continue prescribing blood pressure medication in the morning, until there’s stronger scientific proof to recommend otherwise. 

Evidence that it may not matter when you take your blood pressure medication (as long as you take it)

The HARMONY trial is some of the best evidence we have that it may not matter when people take their blood pressure medication. In this study, researchers randomly assigned people to either morning or nighttime medication. Halfway through the study, participants switched to the other group. 

The researchers found that the time of day a person took their medication did not affect their 24-hour average blood pressure or the blood pressure they had when visiting the clinic.

Research on this topic is ongoing: The TIME study and BedMed study are large, robust trials investigating the risks and benefits of taking blood pressure medication at night versus the morning. 

Hopefully the results of these studies will teach us much more about when someone should take blood pressure medication — and if a person’s daily blood pressure pattern should factor into this decision.

How can I know my own blood pressure pattern?

Taking your blood pressure at home once a day or during a visit to your provider usually doesn’t give a full picture of your blood pressure pattern. Your provider may order a 24-hour ambulatory blood pressure monitoring test to measure your blood pressure changes over a full 24-hour period.

This test uses a small device that connects to a blood pressure cuff to measure your blood pressure every 15 to 30 minutes over 24 hours. This test has become more common since Medicare and Medicaid expanded coverage for it.

Although most smartwatches are not yet equipped to accurately measure 24-hour blood pressure, this technology is rapidly advancing. It will be a very exciting application of wearable heart monitoring techniques — when it’s ready for prime time.

What if I work the night shift?

People who work night shifts are more likely to have abnormal blood pressure patterns and may be more likely to need blood pressure medication. They are also more likely to have heart-related problems, such as atrial fibrillation and CAD. People who work night shifts can improve their overall health by eating well, getting regular exercise, and maintaining a healthy weight. 

Be sure to talk with your healthcare provider if you work the night shift and have difficulty controlling your blood pressure or think you might have an atypical blood pressure pattern. You may need more testing or a change in your blood pressure medication.

So, when’s the best time to take my blood pressure medication?

In the end, the best time to take your blood pressure medication is when you will remember it!

Taking your blood pressure medication every single day — preferably at the same time — is the best way to keep your blood pressure levels within normal limits and your heart and blood vessels healthy in the long term. 

Remember, everyone’s situation is different, and there may be a good reason for you to take your medication at a particular time of day. So create an open line of communication with your healthcare team. That means letting them know about any medication side effects, your sleep patterns, or a history of falls at night. All of these things play a part in the conversation you have with your providers about when it's best for you to take your blood pressure medication.

Why trust our experts?

Written by:

Alice Perlowski, MD, MA, FACC

Dr. Alice Perlowski is a board-certified cardiologist and fellow of the American College of Cardiology. She has seen patients and supervised trainees in the academic and private sector, with focuses in interventional cardiology, vascular medicine, preventative cardiology, and women’s heart health.

Edited by:

Sophie Vergnaud, MD

Sophie Vergnaud, MD, is the Senior Medical Director for GoodRx Health. An experienced and dedicated pulmonologist and hospitalist, she spent a decade practicing and teaching clinical medicine at academic hospitals throughout London before transitioning to a career in health education and health technology.

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