Surgery & Perioperative/Perioperative medication management

Perioperative drug management

also: stop before surgery · bridging · nil by mouth meds · what to hold

Overview

The stop / continue / switch decisions for chronic medications around surgery — a high-yield, rule-dense topic.

Mechanism

Decisions balance the drug's risk during surgery (bleeding, hypoglycaemia, lactic acidosis, hypotension, adrenal crisis) against the harm of stopping it. The patterns are memorable as STOP, CONTINUE, or SWITCH/COVER.

Indications

Any patient on regular medication undergoing surgery

The agents

WarfarinSTOP ~5 days

bridge with LMWH if high thrombotic risk

Check INR <1.5; restart post-op; bridge mechanical valves/recent VTE.

DOACsSTOP 24–48 h

per renal function/bleeding risk

No bridging needed (short half-life).

Metformin / SGLT2iHOLD

Metformin: omit on the day (lactic acidosis/contrast); SGLT2i: stop ~3 days (euglycaemic DKA).

InsulinADJUST / VRIII

Variable-rate IV insulin infusion for major surgery / poor control.

Long-term steroidsCONTINUE + cover

Never stop — give IV hydrocortisone cover (adrenal crisis risk).

COCP / HRTSTOP 4 weeks (major)

VTE risk.

ACE inhibitors / ARBsoften omit on the day

Intra-op hypotension.

Adverse effects

Perioperative bleeding (anticoagulants not stopped)serious

Addisonian crisis (steroids stopped, no cover)serious

Hypoglycaemia / euglycaemic DKA (diabetes meds mismanaged)serious

Thrombosis (anticoagulant stopped without bridging in high-risk)serious

Cautions & contraindications

Stopping long-term steroids abruptlyall

Adrenal crisis — continue + cover.

Continuing an SGLT2 inhibitor through major surgeryall

Euglycaemic DKA.

Interactions

Monitoring & kinetics

INR (warfarin), glucose/ketones, electrolytes, BP

Decisions made at pre-assessment; document clearly on the drug chart.

Source: BNF — Surgery and long-term medication · NICE NG180 — Perioperative care