Your body runs on a roughly 24-hour internal clock, known as the circadian rhythm. It influences sleep, hormones, blood pressure and even how your body responds to medicines. A study from the University of Colorado suggests that timing may matter for one of the most widely used drugs in surgery, the sedative midazolam.
What is chronotherapy?
Chronotherapy is the idea of timing treatments to match the body’s daily rhythms. Because the proteins that drugs act on can behave differently at different times of day, the same medicine may work better, or cause more side effects, depending on when it’s given. Some treatments already follow this idea. For example, certain acid-reflux medicines work best before a meal, and some research has explored whether taking blood pressure medicines in the evening could be helpful for some people.
Researchers argue that timing gets little attention in everyday medicine, partly because many doctors aren’t familiar with chronotherapy and partly because there isn’t enough research on the best timing for most drugs.
What the midazolam study found
Midazolam is the most commonly used sedative in surgical procedures worldwide, and there are no guidelines on what time of day it should be given. The team, led by anesthesiologist Tobias Eckle, analyzed data from 50 medical institutions covering surgeries performed from 2014 to 2019. They looked at how often patients undergoing non-heart surgery developed heart damage during or after their procedures. The study was published in Frontiers in Cardiovascular Medicine.
They found that receiving midazolam during overnight surgeries was linked to more than three times the odds of heart damage in otherwise healthy patients, compared with daytime use.
Important caveats
This was an analysis of existing records, so it shows an association, not proof that midazolam at night causes heart damage. Overnight surgeries are often emergencies, and patients operated on at night may differ in important ways from those scheduled during the day. Staffing, fatigue and the urgency of the procedure may also play a role. The researchers say more studies are needed before any change in practice.
Why this matters
Many common medicines help only a fraction of the people who take them. If timing affects how well drugs work and how safe they are, paying attention to when medicines are given could make existing treatments more effective without developing new drugs. Some medicines might even need to be reformulated to take advantage of the body’s rhythms.
What this means for you
- Don’t change your medication timing on your own. Some drugs need to be taken at specific times, and changing your routine could cause problems. Ask your doctor or pharmacist first.
- Ask about timing. When you start a new medicine, ask whether the time of day matters and whether it should be taken with food.
- Keep a consistent routine. Taking medicines at the same time each day helps keep levels steady and makes it easier to remember.
- If you’re having surgery, it’s fine to ask your anesthesiology team about your medications, risks and what to expect. Most surgeries are scheduled during the day, and emergency procedures happen when they need to.
- Support your body clock. Regular sleep and wake times, morning light and limiting late-night screens all help keep your circadian rhythm healthy.
The bottom line
A large analysis linked overnight use of the common surgery sedative midazolam to higher odds of heart damage. The finding needs confirmation, but it adds to growing interest in how the body’s internal clock affects the way medicines work.
This article is for general information and isn’t medical advice. Talk with your healthcare provider about your individual needs.
