Most surgeons and anesthesiologists will give you a list of medications and supplements to stop before your procedure, but the timelines vary widely. Some drugs need to be paused a full week or more in advance, while others only need to be held the morning of surgery. The specifics depend on the type of medication, your medical conditions, and the procedure itself. Here’s a practical breakdown of what typically needs to stop and when.
Blood Thinners: 2 to 7 Days Before
Blood-thinning medications carry the highest stakes when it comes to surgical bleeding, and they need the longest lead time. Warfarin should be stopped 5 days before surgery. Prescription antiplatelet drugs like clopidogrel (Plavix) and prasugrel need 5 to 7 days, while ticagrelor requires 5 days. These drugs work by irreversibly blocking platelet function, so your body needs time to produce fresh platelets that clot normally.
Newer direct oral anticoagulants like rivaroxaban (Xarelto), apixaban (Eliquis), and dabigatran (Pradaxa) have shorter windows. For higher-risk procedures, they’re typically stopped 48 hours ahead. For lower-risk procedures, 24 hours is often sufficient. If you have reduced kidney function, your body clears these drugs more slowly, so your surgeon may extend the window to 4 days.
If you take aspirin together with another antiplatelet drug (dual therapy), both are usually stopped 7 to 10 days before surgery in patients at low risk for heart events. However, if your surgery can’t be postponed or your cardiac risk is high, your surgical team may decide to continue one or both drugs through the procedure. Never stop a blood thinner on your own without guidance from your prescribing doctor, because the risk of a clot can outweigh the risk of bleeding.
Over-the-Counter Pain Relievers
Common pain relievers sold without a prescription also affect how your blood clots, though to varying degrees. Aspirin, even at low “baby aspirin” doses, should be stopped at least 7 to 10 days before surgery. Ibuprofen (Advil, Motrin) and diclofenac (Voltaren) have a shorter effect on platelets and generally only need to be stopped 1 day before. Naproxen (Aleve) lingers longer in the body and should be stopped about 4 days ahead.
Acetaminophen (Tylenol) does not thin the blood and is usually safe to take up to and including the day of surgery. If you need pain relief in that pre-surgery window, it’s typically the best option.
Diabetes Medications: 3 to 7 Days Before
Two classes of diabetes drugs require special attention before surgery. SGLT2 inhibitors, medications like empagliflozin (Jardiance), canagliflozin (Invokana), and dapagliflozin (Farxiga), should be stopped 3 days before surgery. Ertugliflozin needs at least 4 days. These drugs can trigger a dangerous form of ketoacidosis during and after surgery, sometimes even when blood sugar levels appear normal. The American College of Cardiology specifically flags this risk.
Metformin is generally continued for most patients, but if you have kidney problems or will receive IV contrast dye during the procedure, your doctor may ask you to stop it 24 to 48 hours beforehand.
GLP-1 Drugs Like Ozempic and Wegovy
GLP-1 receptor agonists have gotten significant attention in recent surgical guidelines because they slow stomach emptying. Food or liquid sitting in your stomach during anesthesia raises the risk of aspiration, where stomach contents enter the lungs. Updated 2024 guidance from the American Society of Anesthesiologists and four other medical societies takes a more nuanced approach than earlier blanket recommendations to stop these drugs.
For weekly injections like semaglutide (Ozempic, Wegovy) or tirzepatide (Mounjaro, Zepbound), the current recommendation is to hold the dose for one week before surgery. However, patients at low risk for stomach-emptying problems who aren’t experiencing nausea, vomiting, or abdominal discomfort can often continue their medication.
Patients in the dose-escalation phase (the first 4 to 8 weeks of treatment, when doses are being gradually increased) are at highest risk for delayed emptying. Elective surgery should ideally be deferred until the escalation phase has passed and any digestive side effects have resolved. For patients on higher doses who do proceed with surgery, a liquid-only diet for 24 hours before the procedure is recommended. Your anesthesia team may also use an ultrasound right before surgery to check whether your stomach has emptied.
Blood Pressure Medications: Morning of Surgery
ACE inhibitors (lisinopril, enalapril, ramipril) and ARBs (losartan, valsartan) are typically held the morning of surgery. These drugs can cause a significant drop in blood pressure during anesthesia that’s difficult to correct. Both the Canadian Cardiovascular Society and the Society for Perioperative Assessment and Quality Improvement recommend holding them on the day of surgery.
There’s one important exception: if you take these medications for heart failure with reduced pumping ability, continuing them through surgery is generally the safer choice. Your cardiologist and surgical team will make this call together.
Diuretics (water pills) like hydrochlorothiazide and furosemide are also held the morning of surgery to avoid dehydration and electrolyte imbalances under anesthesia, unless you take them specifically for heart failure. Most other blood pressure medications, including beta-blockers and calcium channel blockers, are continued as normal.
Supplements and Herbal Products
Herbal supplements are easy to overlook, but several carry real surgical risks. Ginkgo biloba increases bleeding risk and should be stopped two weeks before surgery, per Mayo Clinic guidance. Ginkgo is especially concerning when combined with other blood-thinning medications or even ibuprofen. Garlic supplements, ginseng, and ginger in supplement form can also impair clotting and are generally stopped at least one to two weeks ahead.
Fish oil supplements have long been flagged as a bleeding concern, leading many surgeons to ask patients to stop them a week before surgery. However, more recent clinical evidence, including findings from the OPERA randomized trial, found no meaningful increase in surgical bleeding among patients taking fish oil. Despite this, many surgical teams still request you stop it a week out as a precaution. Follow whatever your specific surgeon advises.
Vitamin E in high doses (above what you’d get from a multivitamin) can also affect platelet function. Most institutions recommend stopping high-dose vitamin E supplements about a week before surgery.
Other Medications Held the Morning of Surgery
Several additional drug categories are routinely held on surgery day:
- ADHD medications (stimulants like amphetamine or methylphenidate) can interact with anesthesia and affect heart rate and blood pressure.
- Muscle relaxants like cyclobenzaprine (Flexeril) and carisoprodol (Soma) compound the sedating effects of anesthesia.
- Migraine triptans (sumatriptan, rizatriptan) are held the morning of surgery.
- Bladder medications for overactive bladder (oxybutynin, mirabegron) are paused because of their effects on the nervous system during anesthesia.
- Erectile dysfunction drugs like sildenafil (Viagra) and tadalafil (Cialis) should not be taken the day before or the day of surgery, as they can cause dangerous blood pressure drops under anesthesia.
- Opioid antagonists like naltrexone are held for 48 hours before surgery so that pain medications used during and after the procedure can work properly.
- Bisphosphonates (for osteoporosis) are held the morning of surgery.
Nicotine and Cannabis
No nicotine-containing products should be used on the day of surgery, including cigarettes, vapes, patches, and nicotine gum. Nicotine constricts blood vessels, reduces oxygen delivery to tissues, and impairs wound healing. Many surgeons recommend stopping nicotine as far in advance as possible, ideally several weeks, to improve healing outcomes.
Cannabis products should be stopped at least 72 hours before any procedure involving general anesthesia. The American College of Surgeons warns that marijuana affects the airways, making it harder to place a breathing tube. It can also require higher doses of anesthesia to achieve the same effect, increases the risk of airway obstruction, and reduces blood oxygen levels in ways that slow wound healing. This applies to all forms: smoked, vaped, and edibles.
What You Should Keep Taking
Not everything stops before surgery. Most thyroid medications, seizure medications, beta-blockers, calcium channel blockers, and antidepressants should be taken on schedule, including the morning of surgery, with a small sip of water. Abruptly stopping certain drugs like beta-blockers or anti-seizure medications can be more dangerous than any surgical interaction.
Your surgical team will give you a personalized medication list, and that list should be your primary guide. Bring all of your medications, including supplements, in their original bottles on the day of surgery so the anesthesia team can verify exactly what you’ve been taking and when you last took each one.