Perioperative medication stop-timing

Levothyroxine (T4)

~7-day half-life; perioperative hypothyroidism is dangerous.

Caveat: If NPO for many days, IV levothyroxine ≈75% of the oral dose.

Morning-of, sip water

SPAQI 2020

Liothyronine (T3)

Short half-life — a skipped dose matters more than T4.

Caveat: Do not alter the prescriber's regimen.

Morning-of

SPAQI 2020

Methimazole

Stopping risks thyroid storm.

Caveat: Active hyperthyroidism may warrant delaying elective surgery.

Uninterrupted, incl. day-of

SPAQI 2020

Propylthiouracil (PTU)

Stopping risks thyroid storm.

Caveat: Active hyperthyroidism may warrant delaying elective surgery.

Uninterrupted, incl. day-of

SPAQI 2020

Beta-blockers (metoprolol, atenolol, bisoprolol, carvedilol)

Withdrawal → rebound tachycardia / hypertension / ischaemia.

Caveat: Never START a new beta-blocker pre-op (POISE harm). Hold if bradycardic or hypotensive that morning.

Morning-of

2024 ACC/AHA

Calcium-channel blockers (amlodipine, diltiazem, verapamil)

Smooth control; no withdrawal syndrome.

Morning-of

SPAQI 2022

▲ Clonidine (incl. transdermal patch)

Abrupt withdrawal → severe rebound hypertension.

Caveat: Flag the transdermal patch to anaesthesia.

Morning-of; patch stays on

SPAQI 2022

ACE inhibitors (-pril: ramipril, lisinopril, enalapril)

Risk of refractory intra-op hypotension.

Caveat: STOP-or-NOT (JAMA 2024): either strategy acceptable — continuing → more intra-op hypotension but no worse hard outcomes. CONTINUE if for HFrEF. Genuinely center-dependent.

Commonly hold morning-of (some 24 h prior if high-risk)

2024 ACC/AHA + STOP-or-NOT

ARBs (-sartan: losartan, valsartan, candesartan)

Risk of refractory intra-op hypotension.

Caveat: Same as ACE inhibitors — either strategy acceptable post STOP-or-NOT; continue in HFrEF.

Commonly hold morning-of

2024 ACC/AHA + STOP-or-NOT

Thiazide diuretics (HCTZ, chlortalidone)

Volume depletion / hypotension / electrolyte shifts.

Caveat: Practice varies; low-stakes either way.

Day-of

SPAQI 2022

Loop diuretics (furosemide, bumetanide)

Volume depletion / hypotension.

Caveat: CONTINUE if active heart-failure congestion.

Usually day-of

SPAQI 2022

Statins (atorvastatin, rosuvastatin, simvastatin)

Plaque-stabilising; perioperative continuation favoured.

Caveat: Restart promptly post-op.

Morning-of

2024 ACC/AHA

Metformin

GI upset + theoretical lactic acidosis while fasting.

Caveat: UK permits continue if only 1 meal missed, eGFR ≥45, no IV contrast.

Day-of (US default)

ADA/SAMBA; CCJM 2025

Sulfonylureas (glipizide, glimepiride, glyburide)

Hypoglycaemia while NPO.

Caveat: Stop earlier if on a low-carb pre-op diet.

Day-of

All guidelines

Meglitinides (repaglinide, nateglinide)

Hypoglycaemia (shorter-acting than sulfonylureas).

Caveat: Lower risk than sulfonylureas.

Skip with the missed meal

SAMBA/UK

▲ SGLT2 inhibitors (empagliflozin, dapagliflozin, canagliflozin)

Euglycaemic DKA even with near-normal glucose — highest-stakes oral.

Caveat: FDA-driven. eDKA reported >72 h after stopping — stay vigilant.

Stop 3–4 days before (ertugliflozin 4 d)

FDA; ADA/SAMBA

DPP-4 inhibitors (sitagliptin, linagliptin)

Minimal hypoglycaemia risk.

Caveat: Hold if N/V; some US protocols hold all orals day-of.

Generally morning-of

SAMBA/UK

Pioglitazone (TZD)

Fluid retention concern with major surgery.

Caveat: UK permits continue if ≤1 missed meal.

Day-of (US default)

SAMBA/CCJM 2025

GLP-1 RAs (semaglutide, tirzepatide, dulaglutide, liraglutide)

Delayed gastric emptying → aspiration; routine stopping no longer advised.

Caveat: 2024 multisociety: most continue. Higher-risk (dose-escalation, high dose, weekly>daily, GI symptoms, gastroparesis) → ≥24 h clear-liquid diet, gastric US, treat as full stomach (RSI). Fastest-moving area — confirm institutional protocol.

Most continue (2024); if holding: daily = day-of, weekly = 1 wk prior

2024 multisociety (ASA/AGA/ASMBS/SAGES)

▲ Insulin (basal / prandial / mixed / pump)

Needs an explicit reduction plan (often reduced basal; hold prandial while NPO).

Caveat: Never give the usual full regimen NPO and never omit basal entirely in T1DM (DKA). Bring glucose meter.

Dose-adjusted, not simply skipped

ADA/SAMBA

SSRIs (sertraline, fluoxetine, escitalopram)

Relapse / discontinuation risk outweighs the bleeding signal.

Caveat: Mild ↑ peri-op bleeding (high-bleed surgery only); avoid serotonergic opioids (tramadol/meperidine).

Morning-of

SPAQI 2021

SNRIs (venlafaxine, duloxetine)

Relapse risk; venlafaxine withdrawal is severe.

Caveat: Same bleeding / serotonin caveats as SSRIs.

Morning-of

SPAQI 2021

TCAs (amitriptyline, nortriptyline)

Withdrawal / relapse.

Caveat: Anticholinergic / arrhythmia effects — anaesthesia accounts for these; caution with sympathomimetics.

Morning-of

SPAQI 2021

▲ MAOIs (phenelzine, tranylcypromine, selegiline)

2-week washout risks relapse/suicide; safe anaesthesia is possible.

Caveat: AVOID meperidine, tramadol, methadone, dextromethorphan, methylene blue (serotonin syndrome) and indirect sympathomimetics e.g. ephedrine (hypertensive crisis). USE direct pressors (phenylephrine).

Continue with MAOI-safe technique; do NOT stop without psychiatry

Modern consensus

Lithium

Level swings with fluid/renal/electrolyte shifts; narrow therapeutic window.

Caveat: Watch Na/hydration/renal; prolongs neuromuscular blockade; resume promptly post-op.

Hold ~72 h before major surgery; continue for minor

SPAQI 2021

Antipsychotics (quetiapine, olanzapine, risperidone, aripiprazole, clozapine)

Prevent decompensation.

Caveat: Monitor QT / orthostasis; maintain clozapine continuity.

Morning-of

SPAQI 2021

Benzodiazepines (alprazolam, lorazepam, clonazepam, diazepam)

Withdrawal (seizures / anxiety).

Caveat: Chronic use raises sedative / opioid requirements.

Morning-of

SPAQI 2021

Anticonvulsant mood stabilisers (valproate, lamotrigine, carbamazepine)

Seizure / mood destabilisation if stopped.

Caveat: Carbamazepine is an enzyme inducer.

Morning-of

SPAQI 2021

ADHD stimulants (methylphenidate, amphetamine/Adderall, lisdexamfetamine)

Reduce intra-op hypertension / tachycardia / arrhythmia.

Caveat: If already taken, the case is usually NOT cancelled — tell anaesthesia the last dose; individualise.

Day-of (common)

SPAQI 2021 / periop lit

Aspirin — low dose (75–100 mg)

Frequently continued for secondary cardiovascular / stent protection.

Caveat: Do not stop unilaterally, especially with a coronary stent. Surgeon may stop for very-high-bleed/closed-space surgery.

Often continued

2024 ACC/AHA

Aspirin — higher dose / primary prevention

Primary-prevention aspirin is often stoppable; balance against indication.

Caveat: Confirm indication before stopping.

May stop ~7 days

2024 ACC/AHA

▲ Clopidogrel (Plavix), prasugrel, ticagrelor (P2Y12)

Bleeding vs stent-thrombosis trade-off.

Caveat: Do NOT stop within the mandatory DAPT window after recent stent — cardiology-led plan. Neuraxial: see ASRA timing.

Clopidogrel ~5 d, prasugrel ~7 d, ticagrelor ~3–5 d

ASRA; ACC/AHA

▲ Warfarin

INR normalisation pre-op.

Caveat: Bridging only for high thrombotic risk (mechanical valve, recent VTE/AF stroke). Confirm target INR for procedure.

~5 days before + INR check

ACCP; ASRA

▲ Apixaban (Eliquis), rivaroxaban (Xarelto) — factor Xa DOACs

DOAC clearance is renal-dependent.

Caveat: Neuraxial / deep block timing is longer and renal-adjusted — use the dedicated ASRA reference.

~24–48 h (standard); longer if renal impairment / high-bleed

ASRA 2018

▲ Dabigatran (Pradaxa) — direct thrombin inhibitor

Strongly renal-cleared — washout extends markedly with low CrCl.

Caveat: Renal-adjusted; neuraxial timing per ASRA.

~48 h (normal renal); longer if CrCl reduced

ASRA 2018

▲ LMWH (enoxaparin) — therapeutic / prophylactic

Spinal/epidural haematoma risk.

Caveat: Full renal-adjusted neuraxial timing = ASRA reference.

Prophylactic ≥12 h; therapeutic ≥24 h pre-neuraxial

ASRA 2018

NSAIDs (ibuprofen, naproxen, diclofenac)

Reversible platelet effect + renal/GI concerns.

Caveat: COX-2 selective agents have less platelet effect. Confirm vs surgeon's bleed tolerance.

~3 days (short t½) to ~7–10 days (longer agents) before

Periop lit

Inhaled bronchodilators / ICS (albuterol, Symbicort, Advair)

Optimised airway reduces bronchospasm risk.

Caveat: Patient should bring their own inhaler to theatre.

Continue — bring the inhaler

Periop lit

▲ Chronic oral corticosteroids (prednisone, hydrocortisone)

Abrupt stop → adrenal crisis; HPA suppression needs peri-op cover assessment.

Caveat: Stress-dose decision depends on dose/duration + surgical magnitude (a separate decision tool).

Continue; assess for stress-dose cover

SPAQI / endocrine

Combined oral contraceptive (oestrogen-containing)

Oestrogen raises VTE risk.

Caveat: Balance against unintended-pregnancy risk; not needed for low-VTE-risk/minor surgery. Document pregnancy status.

Consider stopping ~4 wk before high-VTE-risk surgery

Periop / RCOG

HRT (oestrogen-containing)

VTE risk; weigh against menopausal symptom burden + VTE prophylaxis used.

Caveat: Often continued with appropriate thromboprophylaxis — individualise.

Consider stopping ~4 wk before high-VTE-risk surgery

Periop / RCOG

Tamoxifen / raloxifene (SERMs)

Increased VTE risk.

Caveat: Do NOT interrupt adjuvant cancer therapy without oncology input.

Consider holding before high-VTE-risk surgery (oncology-led)

Periop / oncology

PPIs (omeprazole, pantoprazole, esomeprazole)

May be used as aspiration prophylaxis; no withdrawal harm.

Morning-of

Periop lit

Methotrexate

Continuation reduces RA flares without raising infection/wound risk in most studies.

Caveat: Consider holding with significant renal impairment or very high-risk surgery — rheumatology-guided.

Usually continued (normal renal function)

ACR/EULAR periop

Biologic DMARDs (adalimumab, etanercept, infliximab, rituximab)

Infection / wound-healing risk; plan around the dosing interval.

Caveat: Schedule per ACR/EULAR by agent; resume once wound healed + no infection. Rheumatology-led.

Time surgery at the END of the dosing cycle (agent-specific)

ACR/EULAR 2022

Antiepileptics (levetiracetam, phenytoin, lamotrigine, valproate)

Maintain seizure control through the perioperative period.

Caveat: Plan an IV route if prolonged NPO.

Morning-of, sip water

Periop neurology

Gabapentin / pregabalin

Abrupt stop → withdrawal; additive sedation/respiratory effects peri-op.

Caveat: Caution with elderly + opioids (sedation). Avoid NEW high-dose routine pre-medication in frail patients.

Often continued; chronic users continue to avoid withdrawal

Periop lit

▲ Parkinson's medicines (levodopa, dopamine agonists)

Missed doses → severe rigidity / neuroleptic-malignant-like crisis.

Caveat: Give the morning dose; resume ASAP post-op; avoid dopamine antagonists (e.g. metoclopramide).

Continue right up to surgery; minimise NPO gap

Periop neurology

▲ Myasthenia gravis medicines (pyridostigmine)

Affects neuromuscular-blocker response markedly.

Caveat: Specialist + anaesthesia co-management; dose timing individualised.

Continue, but coordinate with anaesthesia (NMB interaction)

Periop neurology

Fish oil / omega-3

Antiplatelet effect at high doses.

Caveat: Low-dose dietary intake less concerning — judge by dose + surgery.

~7 days before

Periop supplement lit

Vitamin E (high-dose)

Platelet inhibition / bleeding risk at high doses.

~7 days before

Periop supplement lit

Garlic, ginkgo, ginseng ('the 3 Gs')

Bleeding (garlic, ginkgo) / glycaemic + cardiovascular effects (ginseng).

Caveat: Default ASA advice: stop most herbals ~1 week pre-op.

~7 days before (ASA general supplement advice)

ASA supplement guidance

Turmeric / curcumin (high-dose)

Possible antiplatelet effect at supplement doses.

Caveat: Culinary amounts not a concern.

~7 days before

Periop supplement lit

St John's wort

Potent CYP / P-gp inducer → altered anaesthetic + drug metabolism.

Caveat: Disclose — significant drug-interaction potential.

~5 days before

ASA supplement guidance

Oral iron

No urgency the morning of; GI tolerability.

Caveat: Pre-op anaemia optimisation (incl. IV iron) is a separate planned pathway.

Day-of (low stakes)

Periop lit

Melatonin

Low risk; sometimes used for peri-op anxiety/sleep.

Caveat: Additive sedation — minor.

Generally fine

Periop lit

Cannabis / CBD

Affects anaesthetic requirements, airway reactivity, and analgesia.

Caveat: Non-judgemental disclosure needed for safe dosing; heavy use raises anaesthetic needs.

Disclose; avoid acute use on the day

Periop lit