Preparing for surgery involves more than just fasting; it requires a meticulous review of all medications, supplements, and herbal products you consume. Ignoring these instructions can lead to serious complications during or after the procedure, including excessive bleeding, blood pressure fluctuations, or dangerous drug interactions with anesthetics. Effective communication with your surgical team and anesthesiologist is key to developing a safe and personalized medication plan.
The Risks of Ignoring Pre-Operative Medication Guidelines
Certain medications pose specific risks when combined with general anesthesia. For example, blood thinners and NSAIDs increase the risk of bleeding, which can complicate a procedure and prolong recovery. Diabetes medications, especially GLP-1 agonists, can slow gastric emptying, increasing the risk of aspiration—a potentially fatal complication where stomach contents are inhaled into the lungs. Blood pressure medications can interact with anesthetics to cause severe drops in blood pressure, making it difficult for the anesthesia team to maintain stable vital signs. Even common herbal supplements can interfere with blood clotting or the effects of anesthesia, which is why transparency with your care team is so important.
Common Medications to Temporarily Discontinue
Anticoagulants and Antiplatelets
These are among the most critical medications to manage before surgery due to the risk of excessive bleeding. Your doctor and surgical team must agree on a specific plan, which may include 'bridging' therapy (temporarily switching to a different, shorter-acting anticoagulant) for high-risk patients.
Common anticoagulants and antiplatelets to hold:
- NSAIDs and Aspirin: Over-the-counter and prescription nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen (Advil, Motrin) and naproxen (Aleve) can inhibit blood clotting. Typically, they must be stopped at least a week before surgery. While low-dose aspirin is often continued for heart health, the decision to stop it is made by your physician based on the type of surgery and your cardiac risk.
- Prescription Blood Thinners: This includes warfarin (Coumadin), clopidogrel (Plavix), and direct oral anticoagulants (DOACs) such as apixaban (Eliquis), rivaroxaban (Xarelto), and dabigatran (Pradaxa). The timeline for stopping these varies, from a few days to a week or more, and must be managed by your doctor.
Diabetes and Weight Loss Medications
Management of these medications is vital to prevent both hypoglycemia (low blood sugar) from fasting and serious complications from specific drug classes.
- GLP-1 Agonists: Medications like semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound) can cause delayed gastric emptying, even if you follow fasting protocols. For weekly injections, they should be held a week before surgery. For daily oral doses, they are typically held the day of the procedure.
- SGLT-2 Inhibitors: These drugs, including canagliflozin (Invokana) and empagliflozin (Jardiance), can increase the risk of euglycemic diabetic ketoacidosis under surgical stress. The US FDA recommends holding these medications at least 3-4 days before surgery.
- Other Oral Diabetes Meds: Sulfonylureas (e.g., glyburide) should be held on the morning of surgery to prevent hypoglycemia. Metformin is also often held on the day of surgery, though guidelines can vary.
Blood Pressure and Cardiac Medications
Managing blood pressure drugs correctly is essential for maintaining stable vital signs during anesthesia.
- ACE Inhibitors and ARBs: Medications like lisinopril and valsartan are often held 12-24 hours before a procedure because they can cause severe hypotension (low blood pressure) when combined with anesthetic agents.
- Diuretics: These fluid pills (e.g., furosemide, hydrochlorothiazide) are generally withheld on the day of surgery to prevent dehydration.
- Beta-Blockers: These are typically continued as they can be protective for the heart. Your doctor will advise you to take them with a small sip of water on the morning of surgery.
Herbal Supplements and Vitamins
Do not assume that 'natural' means safe. Many supplements are not regulated by the FDA and can have potent effects.
Common herbal supplements to stop:
- Bleeding Risk: Garlic, ginger, ginkgo biloba, fish oil, feverfew, and vitamin E all have blood-thinning properties and should be stopped at least one to two weeks before surgery.
- Anesthesia Interference: St. John's wort, kava, and valerian can alter the effects of anesthesia or prolong sedative effects.
Other Important Medications and Substances
- MAOIs and certain Antidepressants: Monoamine oxidase inhibitors (MAOIs) can have dangerous interactions with anesthesia. A plan for discontinuation or adjustment must be made with your prescribing physician.
- Recreational Substances: Alcohol, marijuana, and CBD products can affect heart rate, blood pressure, and pain control and should be avoided before surgery.
Comparison of Common Pre-Operative Medication Adjustments
| Medication Class | Examples | Typical Holding Time | Reason |
|---|---|---|---|
| Anticoagulants | Warfarin (Coumadin), Eliquis, Pradaxa | 5-7 days or as directed | Prevents excessive bleeding |
| NSAIDs | Ibuprofen (Advil), Naproxen (Aleve) | At least 7 days | Inhibits platelet function, increasing bleeding risk |
| GLP-1 Agonists | Semaglutide (Ozempic), Tirzepatide (Mounjaro) | Daily: Day of surgery; Weekly: 7 days prior | Delays gastric emptying, increasing aspiration risk |
| SGLT-2 Inhibitors | Empagliflozin (Jardiance), Canagliflozin (Invokana) | 3-4 days prior | Reduces risk of euglycemic diabetic ketoacidosis |
| ACE Inhibitors/ARBs | Lisinopril, Valsartan | 12-24 hours before surgery | Prevents severe hypotension during anesthesia |
| Diuretics | Furosemide (Lasix) | Morning of surgery | Prevents dehydration while fasting |
| Herbal Supplements | Ginkgo, Garlic, St. John's Wort | 1-2 weeks prior | Risk of bleeding or interaction with anesthesia |
The Golden Rule: Consult Your Healthcare Team
The information provided here is for educational purposes only and should not replace advice from your doctor. Every patient's situation is unique, and a personalized plan is required based on your health history, the type of surgery, and specific medications you take. It is crucial to provide a comprehensive and accurate list of all medications, vitamins, and supplements to your surgical and anesthesia teams during your pre-operative assessment. Do not stop or change any medication without direct instruction from a qualified healthcare provider. The American College of Surgeons offers valuable patient resources for preparing for surgery, which can be found here: https://www.facs.org/for-patients/preparing-for-surgery/medications/.
Conclusion
Prior to general anesthesia, stopping certain medications is a critical safety measure to prevent complications related to bleeding, blood pressure, and anesthetic effects. Blood thinners, NSAIDs, specific diabetes and blood pressure drugs, and a wide array of herbal supplements must be managed with care. The timing and decision to hold each medication should be a collaborative effort between you, your surgeon, and your anesthesiologist. By communicating openly and following their expert guidance, you can significantly reduce risks and contribute to a successful surgical outcome.
