Perioperative Medication Management
Know which pills to keep, which to hold, and which to bridge before the knife
General principles
Continue by default. Most chronic medications should be taken with a sip of water on the morning of surgery, because stopping them is often more dangerous than continuing: β-blockers (rebound ischemia), clonidine (rebound hypertension), antiepileptics (seizures), and benzodiazepines or SSRIs (withdrawal). The exceptions are drugs that cause bleeding, drop blood pressure under anesthesia, cause hypoglycemia or ketoacidosis during fasting, or slow gastric emptying. For each, know how many days ahead to stop and who needs cover with heparin bridging or stress-dose steroids.
Cardiovascular drugs
β-blockers. Continue in patients already taking them, including the morning dose. Never start one on the day of surgery: in the POISE trial, high-dose metoprolol begun hours before surgery reduced MI but increased stroke and death through hypotension and bradycardia. When a new β-blocker is indicated, start it at least 2–7 days ahead and titrate to heart rate and blood pressure.
Statins, clonidine, and others. Continue statins, which stabilize plaque and reduce perioperative cardiac events; starting one before vascular surgery is reasonable. Continue clonidine, because abrupt withdrawal causes a rebound hypertensive crisis. Calcium channel blockers and nitrates continue.
ACE inhibitors and ARBs. These are commonly held the morning of surgery (about 24 hours) because renin-angiotensin blockade plus anesthetic vasodilation produces hypotension that responds poorly to vasopressors. Restart them once the patient is euvolemic and stable. Diuretics are usually held that morning to avoid hypovolemia and hypokalemia.
Anticoagulants and antiplatelet drugs
Warfarin. Stop 5 days before surgery that carries meaningful bleeding risk. Check the INR the day before and give low-dose oral vitamin K if it is still above about 1.5. Resume 12–24 hours after surgery once hemostasis is secure. Minor dental, skin, and cataract procedures can proceed on warfarin.
Bridging. Heparin covers the subtherapeutic window only when thrombotic risk is high:
- Mechanical mitral valve, or an older caged-ball or tilting-disc valve
- Stroke, TIA, or systemic embolism within about 3 months
- VTE within about 3 months, or severe thrombophilia
Therapeutic LMWH starts about 3 days before surgery, once the INR falls, with the last dose 24 hours before; IV unfractionated heparin, preferred in severe renal failure, stops 4–6 hours before. Patients with atrial fibrillation and no recent stroke, a bileaflet mechanical aortic valve without risk factors, or VTE more than 12 months ago simply stop warfarin. In the BRIDGE trial of atrial fibrillation, bridging more than doubled major bleeding without reducing arterial thromboembolism. After an acute VTE, elective surgery should wait at least 3 months.
| Drug | Last dose before surgery | Notes |
|---|---|---|
| Warfarin | 5 days | INR the day before; bridge only if high thrombotic risk |
| Apixaban, rivaroxaban, edoxaban | 1 day (low bleeding risk) or 2 days (high) | No bridging; resume 1 day after low-risk or 2–3 days after high-risk surgery |
| Dabigatran | 1–2 days; 2–4 days if CrCl <50 mL/min | About 80% renally excreted |
| Clopidogrel, ticagrelor | 5 days | Only when unavoidable after a stent; continue aspirin |
| Prasugrel | 7 days | Same caution |
| Aspirin | Continue if stented; about 7 days if taken for primary prevention | Held even with stents for intracranial, spinal canal, or posterior eye surgery |
Coronary stents. Interrupting dual antiplatelet therapy early risks stent thrombosis, which presents as MI with high mortality. Delay elective noncardiac surgery at least 14 days after balloon angioplasty, 30 days after a bare-metal stent, and 6 months after a drug-eluting stent. Continue aspirin through surgery whenever possible; if the P2Y12 inhibitor must stop, restart it as soon as bleeding risk allows. Heparin does not protect a stent.
Diabetes medications
| Drug | Plan | Reason |
|---|---|---|
| Metformin | Hold on the day of surgery | Lactic acidosis with hypoperfusion, contrast, or AKI; resume when eating with stable renal function |
| Sulfonylureas, most other oral agents | Hold the morning of surgery | Hypoglycemia while NPO |
| SGLT2 inhibitors | Stop canagliflozin, dapagliflozin, and empagliflozin 3 days before; ertugliflozin 4 days | Euglycemic DKA; restart only when eating and drinking normally |
| GLP-1 receptor agonists | Continue in most patients (2024 multisociety guidance); if aspiration risk is high (dose escalation, high dose, GI symptoms), hold the daily dose on the day or the weekly dose a week before and consider 24-h clear liquids | Delayed gastric emptying and aspiration |
| Glargine or detemir | Give ~75–80% of the usual dose | Covers basal needs without fasting hypoglycemia |
| NPH | Give ~50% of the morning dose | Its peak falls during the fast |
| Prandial insulin | Hold while NPO; use correction doses | No meal to cover |
Targets and pitfalls. Aim for perioperative glucose of about 100–180 mg/dL. Type 1 diabetics always need basal insulin, since even brief omission can precipitate DKA; pumps continue at the basal rate for short procedures, and long or major operations or poor control call for an IV insulin infusion. Euglycemic DKA on an SGLT2 inhibitor presents as nausea, vomiting, and anion-gap acidosis with ketones while glucose is often below 250 mg/dL; starvation ketosis rarely drives bicarbonate below 18.
Nausea, vomiting, or bloating on the morning of surgery in a patient taking a GLP-1 agonist (semaglutide, liraglutide, tirzepatide) means full-stomach precautions or postponement.
Glucocorticoids and other drugs
Stress-dose steroids. Exogenous glucocorticoids suppress CRH and ACTH, so the adrenal cortex cannot mount the cortisol surge surgery demands, and adrenal crisis follows with hypotension refractory to fluids and pressors. Presume suppression with any supraphysiologic dose (prednisone ≥5 mg/day or equivalent) for ≥4 weeks, or a Cushingoid appearance, and give stress-dose hydrocortisone (2024 ESE/Endocrine Society guideline; older teaching used prednisone ≥20 mg/day for ≥3 weeks): for major surgery, 100 mg IV at induction, then 50 mg every 6 hours (or 200 mg/24 h by infusion), tapering to the usual dose over 1–2 days. Any dose for less than 3 weeks, or less than 5 mg/day, does not suppress the axis and needs only the usual dose; intermediate regimens are covered empirically, and routine preoperative ACTH stimulation testing is not needed. Topical and low-dose inhaled steroids rarely matter.
Herbal supplements. Stop about 2 weeks before elective surgery. Ginkgo (platelet-activating factor inhibition), garlic, and ginseng impair platelets and add to anticoagulant bleeding. St John's wort induces CYP3A4 and lowers levels of cyclosporine, warfarin, and other drugs. Kava and valerian potentiate sedation, and ephedra causes hypertension and arrhythmias.
Neurologic and psychiatric drugs. Continue antiepileptics through the morning of surgery and give IV levetiracetam, valproate, or fosphenytoin while NPO. Continue SSRIs, antipsychotics, and benzodiazepines to avoid withdrawal and relapse. Lithium is often held briefly around major surgery because fluid shifts can push it into the toxic range. With MAOIs, avoid meperidine (serotonin syndrome) and indirect sympathomimetics such as ephedrine (hypertensive crisis); direct-acting pressors such as phenylephrine are preferred.
Other drugs. Levothyroxine, with a half-life of about 7 days, can be skipped for a few NPO days. Inhalers continue and should come to the operating room.