Section 1: Introduction -- The Medication Review Nobody Does Before the Knife

A 67-year-old man in Port of Spain is scheduled for an elective right knee replacement. He takes warfarin for atrial fibrillation, clopidogrel from a drug-eluting stent placed two years ago, metformin for type 2 diabetes, lisinopril for hypertension, atorvastatin for dyslipidaemia, and ibuprofen for post-arthritis pain.

He attends the pre-operative assessment clinic. Nobody reviews his medications. He presents for surgery on the scheduled day having taken all his usual tablets that morning, including the warfarin, the clopidogrel, and the metformin.

His INR is 2.6. His surgery is cancelled.

The cancelled surgery -- and the frustration it causes -- is preventable. The answers to which medications to stop, when to stop them, and when to restart them are not complex. They are, however, rarely communicated systematically between the prescribing clinician, the surgical team, and the patient. In the Caribbean, where primary care, surgical, and anaesthetic services may operate at different facilities without shared records, this communication gap is especially common.

This report provides a single reference for perioperative medication management in Caribbean clinical practice -- covering anticoagulants, antiplatelets, antidiabetics, antihypertensives, statins, NSAIDs, antidepressants, hormonal contraceptives, and herbal products.

Section 2: Anticoagulants -- The Highest-Stakes Perioperative Decision

2.1 Warfarin

Warfarin requires the most careful perioperative planning of any routinely prescribed medication. The decisions depend on the bleeding risk of the procedure and the thromboembolic risk of the indication.

Bleeding risk by procedure:

Thromboembolic risk by indication:

The stop-bridge decision:

For low bleeding risk procedures with a therapeutic INR: continue warfarin without interruption for many minor procedures. Confirm with surgeon.

For high bleeding risk procedures: - Stop warfarin 5 days before surgery - Check INR on the day before -- if above 1.5, administer low-dose oral Vitamin K1 - For high thromboembolic risk patients: bridge with therapeutic-dose LMWH (enoxaparin 1 mg/kg twice daily) starting 3 days before surgery, last dose 24 hours before - For low-moderate thromboembolic risk: no bridging required in most cases -- evidence from the BRIDGE trial shows no significant increase in arterial thromboembolism without bridging in AF patients, with fewer bleeding complications

Restart: Resume warfarin evening of surgery or the next morning. Restart LMWH bridging 48-72 hours post-operatively in high-risk patients, continuing until INR is therapeutic.

2.2 Direct oral anticoagulants (DOACs)

Apixaban, rivaroxaban, dabigatran, edoxaban have shorter half-lives than warfarin, making perioperative management more predictable.

Standard perioperative protocol:

No bridging required with DOACs -- their rapid offset and onset of action makes LMWH bridging unnecessary in most cases.

Restart: 24-48 hours post-operatively for low bleeding risk. 48-72 hours for high bleeding risk. Confirm haemostasis is achieved before restarting.

Section 3: Antiplatelets -- The Drug-Eluting Stent Problem

3.1 Aspirin

Primary prevention aspirin: Stop 7-10 days before surgery. The cardiovascular benefit of aspirin for primary prevention does not justify the bleeding risk perioperatively (Report 4, Drug 16).

Secondary prevention aspirin (established CVD, prior MI, prior stroke): The decision is more complex. In most non-cardiac procedures, the risk of stopping aspirin (rebound platelet hyperactivation, potential acute coronary syndrome) may outweigh the benefit. Current evidence generally supports continuing aspirin through non-cardiac surgery in patients with established CVD. Discuss with the surgical team.

Cardiac surgery (on-pump CABG): Aspirin is typically continued.

3.2 Clopidogrel, prasugrel, ticagrelor

Drug-eluting stent (DES) within 12 months: This is the highest-risk perioperative antiplatelet scenario. Stopping dual antiplatelet therapy (aspirin + clopidogrel/prasugrel/ticagrelor) within the mandatory dual therapy window after DES placement carries a risk of acute stent thrombosis -- a condition with a 45-65% mortality rate.

If surgery can be deferred, defer it until the 12-month dual therapy period is complete.

If surgery cannot be deferred (emergency or urgent): the decision requires cardiology and surgical input. In general, continue aspirin perioperatively, and stop only the P2Y12 inhibitor: - Clopidogrel: stop 5 days before - Prasugrel: stop 7 days before - Ticagrelor: stop 5 days before

BMS (bare metal stent) within 1 month: Same principle -- defer surgery if possible.

Clopidogrel for other indications (stroke, PAD): Stop 5 days before high-risk procedures. Continue for low-risk procedures.

Restart: Clopidogrel should be restarted as soon as bleeding risk allows, ideally within 24-48 hours post-operatively in DES patients.

Section 4: Antidiabetics -- The Glucose Management Challenge

4.1 Metformin

Stop 48 hours before any procedure involving iodinated contrast media (CT with contrast, cardiac catheterisation, angiography) -- risk of metformin-associated lactic acidosis if contrast causes acute kidney injury. Restart 48 hours post-procedure once renal function is confirmed stable.

Major surgery: Stop on the morning of surgery. Restart when the patient is eating and drinking normally and renal function is stable.

Minor or low-risk surgery (e.g. day case under local anaesthetic): May be continued if the patient will not receive contrast and is not expected to have significant renal impairment.

4.2 Sulfonylureas

Stop on the morning of surgery. Hypoglycaemia risk during a fasting period in which the patient cannot eat. Do not restart until the patient is eating normally.

4.3 SGLT2 inhibitors

Stop 3 days before major surgery. Risk of euglycaemic diabetic ketoacidosis perioperatively -- the fasting state, reduced carbohydrate intake, and surgical stress can precipitate DKA even at normal glucose levels (Report 8, Section 2.3).

4.4 Insulin

Do not stop insulin in type 1 diabetes -- basal insulin must continue at all times; even fasting patients require basal insulin to prevent DKA.

For type 2 diabetes on insulin: Reduce basal insulin by 20-25% on the evening before and morning of surgery. Hold bolus insulin until the patient is eating. Target intraoperative glucose 6-10 mmol/L.

GLP-1 receptor agonists (semaglutide, liraglutide): Stop on the day of surgery. Delayed gastric emptying increases aspiration risk under general anaesthesia, particularly for same-day procedures where fasting time may be uncertain (Report 14).

Section 5: Antihypertensives -- What to Continue, What to Stop

5.1 ACE inhibitors and ARBs

Standard guidance: Hold ACE inhibitors and ARBs on the morning of surgery. Intraoperative hypotension is significantly more common in patients who take ACE inhibitors or ARBs within 10 hours of surgery.

The VISION trial and subsequent evidence demonstrate that perioperative continuation of ACE inhibitors/ARBs is associated with clinically significant intraoperative hypotension requiring vasopressor support.

Exception: Continue in patients with heart failure where stopping risks haemodynamic decompensation -- discuss with the anaesthetic team.

Restart: Resume the morning after surgery once the patient is haemodynamically stable and tolerating oral intake.

5.2 Beta-blockers

Continue. Do not stop beta-blockers perioperatively. Abrupt withdrawal can cause rebound tachycardia, hypertension, and angina. Continue the usual dose up to and including the morning of surgery.

5.3 Calcium channel blockers

Continue. Amlodipine and other CCBs can be taken with a sip of water on the morning of surgery. Their perioperative haemodynamic effects are generally acceptable, and abrupt cessation is not recommended.

5.4 Diuretics

Generally hold on the morning of surgery. Diuretics increase the risk of perioperative volume depletion and electrolyte disturbance. In patients with heart failure who are diuretic-dependent, discuss with the anaesthetic team.

5.5 Clonidine and methyldopa

Do not stop abruptly. Clonidine cessation causes rebound hypertension (Report 9). Continue up to and including the morning of surgery. Resume post-operatively as soon as possible.

Section 6: Other Drug Classes

6.1 Statins

Do not stop. Continue statins through the perioperative period. Evidence suggests that perioperative statin continuation reduces cardiovascular events in patients undergoing major non-cardiac and cardiac surgery. Stopping statins perioperatively may increase the risk of myocardial injury.

6.2 NSAIDs

Stop 5-7 days before surgery in most cases. Non-selective NSAIDs inhibit platelet thromboxane A2 synthesis irreversibly -- platelet function does not recover until new platelets are produced (approximately 7-10 days). The risk of perioperative bleeding is increased with NSAID use.

Celecoxib (selective COX-2 inhibitor): Does not inhibit platelet thromboxane -- no need to stop for bleeding risk. However, its cardiovascular effects and renal effects remain relevant in the perioperative context.

OTC NSAID use: Patients often do not report OTC ibuprofen use because they do not consider it a "medication." The pre-operative medication history must specifically ask about over-the-counter NSAIDs (Report 6, Report 7).

6.3 SSRIs and SNRIs

Continue SSRIs through surgery in most cases. SSRIs reduce platelet serotonin, which contributes to a small increase in surgical bleeding -- but the risk of discontinuation syndrome and depression relapse from abrupt stopping outweighs this modest haemostatic effect. Inform the surgical team so that the bleeding risk is acknowledged.

Do not stop abruptly. Paroxetine and venlafaxine have severe discontinuation syndromes (Report 11).

6.4 Monoamine oxidase inhibitors (MAOIs)

Stop 2 weeks before surgery. MAOIs interact with opioids used for anaesthesia (particularly pethidine) causing potentially fatal serotonin syndrome and hypertensive crises. This requires psychiatric input before stopping.

6.5 Combined oral contraceptives

Stop 4 weeks before major surgery. Oestrogen-containing contraceptives increase the risk of deep vein thrombosis and pulmonary embolism perioperatively through increased clotting factor production. The risk is highest in prolonged procedures under general anaesthesia with immobility.

Switch to a progestogen-only method or use barrier contraception for the 4 weeks pre-operatively and until fully mobile post-operatively.

Progestogen-only contraceptives (POP, Depo-Provera, LNG-IUD): No need to stop.

6.6 Herbal products

Stop all herbal products 2 weeks before surgery. No specific stop dates have been validated for individual herbal products, but the following interactions are documented:

Caribbean patients frequently use herbal products and rarely disclose them. The three questions from Report 3 should be part of every pre-operative assessment.

Section 7: The Perioperative Medication Checklist

For the clinician conducting the pre-operative medication review.

Section 8: About ElesRx

ElesRx identifies perioperatively relevant drugs in a patient's medication list. When a patient is flagged as having an upcoming surgical procedure, the system identifies anticoagulants, antiplatelets, antidiabetics, ACE inhibitors, NSAIDs, oestrogen-containing contraceptives, and herbal products, and generates a summary of perioperative actions for each.

The tool is available at elesrx.com. ElesRx is a product of PIPPS Smart Apps, a division of J.C. Epiphany Limited (Jamaica, est. 1998).

Section 9: Methodology and References

9.1 Data sources

Perioperative medication management guidance is drawn from the ElesRx clinical database, DailyMed, the American College of Cardiology/American Heart Association perioperative guidelines, the British Society of Haematology guidelines on perioperative anticoagulation, and the European Society of Anaesthesiology guidelines.

9.2 Limitations

Perioperative medication management in high-risk patients -- those with mechanical heart valves, recent acute coronary syndrome, severe heart failure, or complex anticoagulation indications -- requires specialist input from cardiology, haematology, and anaesthetics. This report provides a general framework for outpatient and primary care pre-operative review; it does not replace specialist consultation in complex cases.

9.3 Author and conflict of interest disclosure

This report was authored by Juliet Duncan, BPharm, founder of J.C. Epiphany Limited and developer of ElesRx. The author has a commercial interest in ElesRx. This report is published without an access gate as a contribution to Caribbean clinical education. No external funding was received.

9.4 Citation

Duncan J. The Perioperative Report: What to Stop Before Surgery, When to Stop It, and When to Restart. ElesRx Clinical Reports, Report 18. Published 2027 at elesrx.com/reports/perioperative-report/. J.C. Epiphany Limited, Jamaica.

References

1. Douketis JD, Spyropoulos AC, Kaatz S, et al. Perioperative bridging anticoagulation in patients with atrial fibrillation (BRIDGE trial). N Engl J Med. 2015;373(9):823-833. doi:10.1056/NEJMoa1500150

2. Kristensen SD, Knuuti J, Saraste A, et al. 2014 ESC/ESA Guidelines on non-cardiac surgery: cardiovascular assessment and management. Eur Heart J. 2014;35(35):2383-2431. doi:10.1093/eurheartj/ehu282

3. Fleisher LA, Fleischmann KE, Auerbach AD, et al. 2014 ACC/AHA guideline on perioperative cardiovascular evaluation and management of patients undergoing noncardiac surgery. Circulation. 2014;130(24):e278-e333. doi:10.1161/CIR.0000000000000105

4. Eberhart LH, Morin AM, Kranke P. Perioperative management of patients with drug-eluting stents. Anaesthesist. 2009;58(9):889-902. doi:10.1007/s00101-009-1605-x

5. Levy JH, Tanaka KA. Inflammatory response to cardiopulmonary bypass. Ann Thorac Surg. 2003;75(2):S715-S720. doi:10.1016/S0003-4975(02)04701-X