Most medications you take daily can be continued right up to surgery, but several common ones need to be paused days or even weeks in advance. Blood thinners, certain diabetes drugs, pain relievers, hormonal birth control, and some supplements all carry risks during a procedure if they’re still active in your system. Your surgical team will give you a personalized list, but understanding the general timelines helps you ask the right questions and avoid surprises.
Blood Thinners and Anticoagulants
These medications carry the highest stakes because they directly affect your body’s ability to form clots and control bleeding during surgery. The stop time depends on how long each drug stays active.
Warfarin needs to be stopped at least five days before a procedure. It works slowly and clears slowly, so your body needs that full window to regain normal clotting ability. After surgery, it’s typically restarted 12 to 24 hours later once bleeding is under control.
Newer blood thinners like apixaban (Eliquis) and rivarobaxan (Xarelto) clear faster. For most people with healthy kidneys, stopping one to two days before surgery is enough. If your kidneys don’t filter as efficiently, your surgeon may ask you to stop earlier since these drugs take longer to leave your system.
Clopidogrel (Plavix), which prevents platelets from clumping together, should be stopped five days before surgery. This is the same timeline as warfarin, even though it works through a completely different mechanism.
Aspirin and Over-the-Counter Pain Relievers
Aspirin permanently changes your platelets’ ability to clot. Since your body replaces its full supply of platelets over roughly ten days, that’s how long you need to stop aspirin before surgery to completely eliminate its blood-thinning effect. If your doctor has you on aspirin for a heart condition, they’ll weigh the clotting risk against the bleeding risk rather than automatically stopping it.
Other common pain relievers like ibuprofen (Advil, Motrin) and naproxen (Aleve) also thin the blood, but their effects wear off faster. Stopping these 48 hours before surgery is generally sufficient. The concern isn’t just bleeding: these drugs can also stress the kidneys during a procedure when blood flow and hydration are already compromised. Acetaminophen (Tylenol) does not thin the blood and is usually safe to take before surgery, though you should confirm with your surgical team.
Herbal Supplements and Vitamins
Supplements often fly under the radar during pre-surgical planning, but several popular ones affect clotting. Fish oil, garlic supplements, ginkgo biloba, and high-dose vitamin E can all interfere with your blood’s ability to coagulate. Most surgeons recommend stopping these at least one to two weeks before a procedure to be safe.
The tricky part is that supplements aren’t regulated the same way as medications, so their potency can vary widely between brands. Be sure to mention every supplement you take during your pre-op appointment, even if it seems harmless. Many patients forget to list these because they don’t think of them as “real” medications.
Hormonal Birth Control and Estrogen
Estrogen-containing medications, including combination birth control pills, patches, rings, and hormone replacement therapy, raise your risk of blood clots. Surgery compounds that risk because you’re immobile during and after the procedure, which slows blood flow in your legs.
Research from the American Society of Hematology found that about 80% of the increased clotting risk from hormonal birth control drops within two weeks of stopping, and 85% within four weeks. Based on this, stopping two to four weeks before surgery is typically sufficient. Your surgeon will factor in the type of procedure and your personal clot risk. If you do stop birth control, use a backup contraceptive method in the meantime.
Diabetes Medications
Two categories of diabetes drugs require special attention before surgery.
SGLT2 Inhibitors
Drugs like empagliflozin (Jardiance) and dapagliflozin (Farxiga) lower blood sugar by pushing excess glucose out through your urine. The problem is they can trigger a rare but dangerous condition called euglycemic ketoacidosis, where your blood becomes dangerously acidic even though your blood sugar reads normal. Because the numbers look fine, this complication can go undetected until it becomes serious. The American Diabetes Association recommends stopping most SGLT2 inhibitors three days before a scheduled surgery.
GLP-1 Medications
Semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound) have created some confusion in the surgical world. The main concern is that these drugs slow stomach emptying, which could mean food remains in your stomach despite fasting, raising the risk of aspiration during anesthesia.
However, updated 2025 guidelines from the Australian and New Zealand College of Anaesthetists recommend against routinely stopping these medications before surgery. Their reasoning: stopping for one to two weeks, as some earlier guidance suggested, is unlikely to actually change gastric emptying, and pausing the medication risks destabilizing blood sugar control or weight management. For semaglutide, you’d need to stop for roughly three to four weeks (four half-lives of about 6 days each) to fully clear the drug’s effect on stomach emptying. For tirzepatide, the math works out to about two to four weeks.
Guidelines on this topic are still evolving, and different surgical centers may have different policies. Bring this up with both your prescriber and your anesthesiologist well in advance so everyone is on the same page.
Psychiatric Medications
Most psychiatric medications, including antidepressants and anti-anxiety drugs, should be continued through surgery. Abruptly stopping them risks withdrawal symptoms or a relapse of the condition they’re treating, which complicates recovery.
Benzodiazepines for anxiety (like lorazepam or diazepam) are particularly important to keep taking. Sudden withdrawal can cause anxiety, dizziness, tremors, and in severe cases, seizures. Current consensus recommends taking these on the morning of surgery as usual. If you can’t swallow pills after a procedure, intravenous alternatives are available.
There are rare exceptions. Certain older antidepressants called MAOIs can interact with anesthesia drugs, so your anesthesiologist needs to know about them. But the decision to adjust or continue these medications is made on a case-by-case basis, not as a blanket rule.
Medications You Should Keep Taking
Blood pressure medications, including beta-blockers and calcium channel blockers, should generally be taken on the morning of surgery with a small sip of water. Stopping beta-blockers abruptly can cause a dangerous rebound spike in heart rate and blood pressure, which is the last thing you want going into an operating room. The same goes for most heart medications and seizure medications.
The general rule at most surgical centers: unless you’re specifically told to skip a medication, continue your daily routine with a sip of water even when you’re otherwise fasting before surgery. The fasting instructions (no food or drink after midnight, for example) don’t apply to approved medications taken with a minimal amount of water.
How to Prepare Your Medication List
Bring a complete, written list of everything you take to your pre-operative appointment. This includes prescriptions, over-the-counter drugs, vitamins, supplements, and anything you take only occasionally (like ibuprofen for headaches). For each one, note the dose and how often you take it.
Your surgical team will go through the list and tell you exactly what to stop, when to stop it, and what to keep taking. If you see multiple specialists who each prescribe different medications, make sure your surgeon knows about all of them. The most dangerous gaps in pre-surgical planning happen when a medication isn’t on the list because no one thought to mention it.
If you realize you forgot to stop a medication on time, call your surgeon’s office rather than guessing. In some cases the procedure can still go forward; in others, rescheduling is the safer choice. Either way, being honest about what you’ve taken is far better than risking a complication on the operating table.