NPO means “nothing by mouth,” but it does not automatically include all medications. In most cases, you will be asked to take essential prescription medications on the morning of your procedure with a small sip of water, roughly 1 ounce. However, certain medications need to be stopped or adjusted beforehand, so the answer depends on which drugs you take and what kind of procedure you’re having.
Why NPO Exists
The main concern behind NPO orders is aspiration, which happens when stomach contents enter the lungs while you’re under anesthesia. When you’re sedated, the reflexes that normally prevent food or liquid from going down the wrong way are suppressed. Fasting before a procedure keeps your stomach empty enough to minimize that risk.
Clear liquids leave the stomach quickly, often passing into the small intestine within about 10 minutes. That’s why current guidelines from the American Society of Anesthesiologists allow clear liquids up to 2 hours before a procedure requiring anesthesia or sedation. Solid food takes much longer to empty, which is why the cutoff for food is earlier, typically 6 to 8 hours. A single pill swallowed with a sip of water adds almost nothing to your stomach volume, which is why most medications are still permitted.
Medications You’ll Typically Still Take
Most chronic medications should be taken on the morning of surgery with a small sip of water. The general principle is that skipping important daily medications carries more risk than the tiny amount of water needed to swallow them. Blood pressure medications, heart rhythm drugs, seizure medications, and thyroid hormones almost always fall into this category.
Beta blockers for blood pressure or heart rate are a clear example. Stopping them abruptly can cause rebound spikes in heart rate and blood pressure, so they are continued through the day of surgery. If you can’t swallow pills after the procedure, intravenous versions are available for several common blood pressure medications.
Seizure medications are also considered essential to continue. Skipping even one dose can lower the seizure threshold. If a longer period without oral intake is expected after surgery, your care team may switch you to an intravenous form or a substitute that has one available.
Acid reflux medications like proton pump inhibitors are often encouraged before surgery, not restricted. The ASA guidelines note that medications blocking gastric acid secretion may be given preoperatively to patients at higher risk of aspiration. Reducing stomach acidity makes any potential aspiration less damaging to the lungs.
Medications That Get Held or Adjusted
Not every medication is safe to take on an empty stomach before anesthesia. A few categories are routinely stopped or modified.
- Diabetes medications: Oral blood sugar drugs, especially those that stimulate insulin release (like sulfonylureas), are typically held the morning of surgery because you won’t be eating and they could drive your blood sugar dangerously low. Metformin is usually stopped when fasting begins, particularly for longer surgeries or procedures involving contrast dye. Basal insulin is not stopped entirely but is often reduced by about 25% the evening before or morning of surgery to prevent low blood sugar while you’re not eating.
- Blood thinners: These follow a different timeline entirely. Warfarin is usually stopped 5 days before surgery. Newer blood thinners like apixaban and rivaroxaban are stopped 24 to 48 hours beforehand depending on the bleeding risk of the procedure and how well your kidneys work. Aspirin, on the other hand, often does not need to be stopped for many procedures. If you have a coronary stent and take dual antiplatelet therapy, the plan for stopping those medications will be made on a case-by-case basis, often 7 to 10 days before surgery.
- Certain blood pressure drugs: ACE inhibitors and ARBs (common blood pressure medications ending in “-pril” or “-sartan”) are sometimes held the morning of surgery because they can contribute to significant drops in blood pressure under anesthesia. Practice varies on this. Some guidelines recommend continuing them, especially for patients with heart failure, while others suggest skipping the morning dose. Your surgical or anesthesia team will tell you which approach to follow. Diuretics (water pills) are also often held the morning of surgery to avoid dehydration.
How Much Water You Can Use
When your instructions say to take medications with a “sip of water,” that means about 1 ounce, or roughly two tablespoons. You are not drinking a full glass. This tiny volume empties from the stomach almost immediately and does not meaningfully increase aspiration risk. Do not use juice, milk, or coffee to wash down pills, as those have calories or particles that slow stomach emptying.
NPO Rules for Children
Children follow similar principles, with one notable difference: the fasting window for clear liquids is shorter. While adults are asked to stop clear liquids 2 hours before a procedure, children may be allowed clear liquids up to 1 hour beforehand. Medications for children are still given with a small sip of water just as they are for adults, but the specific instructions will come from the pediatric anesthesia team.
What Happens in an Emergency
If you need emergency surgery and haven’t been fasting, the situation changes. There isn’t time for the standard NPO window, so the anesthesia team uses other strategies to protect your airway during the procedure. Your home medications are reviewed quickly, and anything critical, like blood pressure or seizure drugs, may be given through an IV if you can’t take them by mouth. The focus shifts from ideal preparation to managing the risks in real time.
What Your Instructions Should Tell You
Before any procedure requiring sedation or anesthesia, you should receive a specific medication list from your surgical team telling you exactly which drugs to take and which to skip on the morning of the procedure. If you only get a blanket “NPO after midnight” instruction with no mention of medications, call your surgeon’s office or the pre-admission nurse and ask. Bring all your current medications or a complete list to every pre-surgical appointment so nothing gets overlooked.
The short answer: NPO restricts food and drink, but most essential medications are still taken with a tiny sip of water. The exceptions, primarily diabetes drugs, blood thinners, and certain blood pressure medications, follow their own specific timelines that your care team should spell out for you in advance.