Propofol basics

What propofol is (and why we use it)

• Propofol is an intravenous (IV) hypnotic agent: it produces unconsciousness (and sedation) but is not an analgesic (it does not treat pain).
• Common uses: induction of general anaesthesia, maintenance (often via infusion/TIVA), procedural sedation (with appropriate monitoring and skills).
• Typical effects: rapid onset, smooth induction, anti-emetic properties, quick recovery when used appropriately.

Formulation and presentation

• Usually supplied as a white lipid emulsion (e.g. 10 mg/mL = 1%).
• Common sizes: 20 mL (200 mg), 50 mL (500 mg); check local stock and concentration before drawing up.
• Lipid emulsion supports bacterial growth: use strict aseptic technique, label syringes, and follow local guidance on discard times (often within hours once drawn up).
• Can cause pain on injection (especially small hand veins).

Mechanism (simple exam-friendly version)

• Main action: enhances inhibitory neurotransmission at the GABA-A receptor in the brain, producing hypnosis/sedation.
• No reliable analgesia: if the procedure is painful, plan opioids/regional/local anaesthesia as appropriate.

Dosing: induction (adult) – practical starting points

• Healthy adult induction: often 1.5–2.5 mg/kg IV, titrated to effect (give in small increments while watching response).
• Older/frail patients: start much lower (e.g. 0.5–1 mg/kg total, titrated slowly).
• Haemodynamic compromise (sepsis, hypovolaemia, severe cardiac disease): reduce dose substantially and titrate carefully.
• Obesity: dosing depends on context; for induction many clinicians dose to lean body weight or adjusted body weight rather than total body weight to avoid overdose—follow local practice and senior advice.
• Always match dose to patient physiology and co-administered drugs (opioids/benzodiazepines reduce propofol requirement).

Dosing: sedation and infusions (intro level)

• Sedation: use small boluses (e.g. 10–20 mg at a time) or low-rate infusion, titrating to a defined sedation target.
• Propofol sedation can quickly become general anaesthesia: only provide it where airway/ventilation rescue is immediately available and you are trained/equipped to manage it.
• TIVA/infusion: use a pump and a clear plan for monitoring depth, ventilation, and haemodynamics; follow local protocols (including target-controlled infusion if used).

Expected physiological effects (what you will see)

• Cardiovascular: vasodilation and reduced cardiac contractility can cause hypotension; bradycardia can occur (rarely severe).
• Respiratory: dose-dependent respiratory depression and apnoea are common after induction bolus; airway obstruction can occur during sedation.
• CNS: rapid loss of consciousness; occasional excitatory movements/myoclonus can occur.
• Other: anti-emetic effect; no analgesia; reduces airway reflexes.

Before you give propofol: a safe checklist for new starters

• Confirm indication and plan: induction vs sedation; what is your airway plan and backup plan?
• Check monitoring is on and working: ECG, NIBP, SpO2; capnography whenever ventilating or providing sedation where airway compromise is possible (and per local policy).
• IV access: ensure a functioning cannula; consider a larger vein if possible to reduce injection pain and ensure reliable delivery.
• Resuscitation readiness: oxygen on, suction available, bag-mask ready, airway adjuncts nearby; vasopressor prepared if high risk.
• Pre-oxygenate for induction; consider fluid/vasopressor strategy if hypotension likely.
• Draw up and label clearly: concentration, drug name, date/time; use aseptic technique.

Managing common first-time scenarios

• Hypotension after induction: reduce further propofol, ensure oxygenation/ventilation, check pulse/ECG; treat with fluids if appropriate and vasopressor (e.g. metaraminol/phenylephrine per local practice); consider other causes (bleeding, anaphylaxis, high spinal, arrhythmia).
• Apnoea after bolus: this is expected—support ventilation with bag-mask, ensure airway patency, use adjuncts early, and confirm with capnography.
• Pain on injection: use a larger vein (antecubital), give lidocaine (e.g. 10–40 mg IV) before or mixed (per local policy), consider a small opioid dose, and inject slowly.
• Inadequate effect: check IV patency/extravasation, confirm drug/concentration, consider high sympathetic tone (pain/anxiety) and need for opioid/adjunct, titrate carefully.
• Unexpected movement/coughing: may indicate light anaesthesia or airway stimulation—deepen anaesthesia appropriately and ensure adequate analgesia; check you are not in an unsafe sedation zone.

Contraindications and cautions (practical)

• No absolute contraindication in most settings, but use extra caution in: severe haemodynamic instability, hypovolaemia, severe cardiac failure, and the very elderly/frail.
• Allergy: true propofol allergy is rare; check history of previous reactions to anaesthesia. (Food allergies such as egg/soy are not usually a contraindication, but treat any prior anaphylaxis to propofol as significant and escalate.)
• Pregnancy/obstetrics and critically unwell patients: dosing and physiology differ—seek senior input early.
• Avoid prolonged high-dose infusions without appropriate critical care monitoring due to risk of Propofol Infusion Syndrome (PRIS).

Propofol Infusion Syndrome (PRIS) – recognition (intro)

• Rare but life-threatening, classically with prolonged high-dose infusions (often in ICU), especially with catecholamines and steroids.
• Features: unexplained metabolic acidosis, rhabdomyolysis, hyperkalaemia, acute kidney injury, arrhythmias, cardiovascular collapse.
• If suspected: stop propofol, escalate immediately, supportive critical care management.