Q4 LONG ANSWER 10M ★ High-yield

Describe Premedication in detail.

General Surgery · Final Professional

Definition & Aims

Premedication is the administration of drugs before anaesthesia to prepare the patient. Its aims are classically remembered as the ‘several As’: Anxiolysis (relieve anxiety), Amnesia, Analgesia, Antisialagogue (reduce secretions), Anti-emesis, Antacid/Aspiration prophylaxis, and Attenuation of autonomic (vagal) responses — plus continuation of essential regular medication.

Purpose	Drug examples
Anxiolysis / amnesia / sedation	Benzodiazepines (midazolam, diazepam)
Analgesia	Opioids (morphine), NSAIDs, paracetamol
Antisialagogue / antivagal	Anticholinergics (atropine, glycopyrrolate)
Anti-emesis	Ondansetron, metoclopramide, dexamethasone
Aspiration prophylaxis	H₂ blocker/PPI, sodium citrate, metoclopramide

Choosing Premedication

Premedication is tailored to the patient and procedure, not routine. A benzodiazepine (e.g. Oral midazolam) relieves anxiety and provides amnesia
anticholinergics reduce secretions and blunt the vagal bradycardia caused by some drugs and airway manipulation
anti-emetics reduce postoperative nausea and vomiting
analgesics contribute to multimodal pain control. Children may receive oral or intranasal sedation, and topical local anaesthetic cream for cannulation.

Continuation & Omission of Regular Drugs

Most regular medications are continued through surgery (e.g. Antihypertensives — though ACE inhibitors/ARBs are sometimes withheld on the day; anti-anginals; inhalers; steroids). Some are adjusted or withheld: anticoagulants/antiplatelets (balancing bleeding and thrombosis), oral hypoglycaemics/insulin (adjusted for fasting), and certain others. This medication review is a key part of premedication.

CLINICAL PEARL

Remember the aims of premedication as the ‘A’s: Anxiolysis, Amnesia, Analgesia, Antisialagogue, Anti-emesis, Antacid (aspiration prophylaxis) and Attenuation of vagal reflexes. Premedication is selective, chosen for the individual, not given to everyone.

DANGER / REMEMBER

Sedative premedication must be used cautiously in the elderly, those with respiratory compromise or obstructive sleep apnoea, and in emergencies/full-stomach patients, where it can cause respiratory depression or obtund airway reflexes — and it should not delay urgent surgery.

Timing & Routes

Premedication is timed and routed to suit its purpose: oral drugs are given with a sip of water an hour or so before surgery, while drugs needed rapidly (or in a patient who cannot swallow) are given intravenously in the anaesthetic room. In children, palatable oral or intranasal sedatives and topical local-anaesthetic cream for cannulation are particularly valuable in reducing distress. The choice always balances the benefit of a calm, comfortable, protected patient against the risks of over-sedation, and increasingly there is a move away from routine heavy sedative premedication towards a targeted approach and good preoperative explanation and reassurance, which itself reduces anxiety and the need for drugs.

CLINICAL PEARL

Two ideas capture premedication: it is a menu, not a fixed prescription — you pick the ‘A’s the individual patient needs — and the most important single decision it contains is often the review of regular medications, deciding what to continue, adjust or stop around surgery.

DANGER / REMEMBER

Sedative premedication is not free of hazard: in the elderly, in respiratory disease or obstructive sleep apnoea, and in the unfasted emergency patient it can cause respiratory depression, airway obstruction or blunted protective reflexes, and it must never be allowed to delay urgent surgery. It is prescribed selectively, in reduced doses in the vulnerable, and with monitoring where appropriate.

Reduces anaesthetic requirement and smooths induction.

KEY POINT

Key points TO remember

Premedication = drugs before anaesthesia; aims = the ‘A’s (anxiolysis, amnesia, analgesia, antisialagogue, anti-emesis, antacid, attenuate vagal).
Benzodiazepines (anxiolysis/amnesia), anticholinergics (secretions/vagal), anti-emetics, analgesics.
Tailored to patient & procedure — not routine.
Continue most regular drugs; adjust anticoagulants, antiplatelets, diabetic drugs; care with ACE-I/ARB.
Cautious sedation in elderly, respiratory disease/OSA, and full-stomach patients.

EXAM TIP

Sources: Morgan & Mikhail’s Clinical Anesthesiology; Miller’s Anesthesia; Ajay Yadav’s Short Textbook of Anaesthesia.

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