Describe Propofol in detail.

Pharmacology

Propofol is the most widely used intravenous induction agent. It is presented as a white lipid emulsion and acts via GABA_A potentiation. Its induction dose is 1.5–2.5 mg/kg. It has a rapid onset and a rapid, clear recovery (short context-sensitive half-time), which — with its anti-emetic property — makes it excellent for day-surgery and for total intravenous anaesthesia (TIVA) by infusion.

Uses

Propofol is used for induction, maintenance (TIVA/TCI), and sedation (in ICU and for procedures). Its smooth recovery and anti-emetic effect are valued in day-case and in patients prone to postoperative nausea and vomiting.

Adverse Effects

Cardiovascular: dose-dependent hypotension (vasodilatation and myocardial depression) — marked in the elderly, hypovolaemic or cardiovascularly compromised. Respiratory: apnoea and respiratory depression at induction. Injection: pain on injection (reduced by a large vein and adding lidocaine). It has no analgesic effect. Rarely, prolonged high-dose infusion (especially in critically ill patients/children) causes propofol infusion syndrome.

Practical Points

Because it is a lipid emulsion, propofol supports bacterial growth, so strict asepsis and prompt use of opened ampoules are essential. Pain on injection is minimised by using a larger vein and co-administering lidocaine. It is combined with an opioid (for analgesia) and, where needed, a muscle relaxant.

Comparison & Place in Practice

Propofol has become the default induction agent precisely because its profile suits so much of modern, day-case and ambulatory anaesthesia: the recovery is not merely rapid but clear-headed, patients feel well, and the anti-emetic effect reduces one of the commonest causes of delayed discharge and patient dissatisfaction. Its ability to be run as an infusion, alone or as part of total intravenous anaesthesia, extends its usefulness from a single induction bolus to maintenance of anaesthesia and to sedation in the intensive care unit and for procedures, so a single familiar drug covers a very wide range of clinical needs.

Cautions & Special Populations

Propofol’s cardiovascular depression makes dose reduction essential in the elderly, the hypovolaemic and those with limited cardiac reserve, in whom a standard dose can produce profound hypotension; conversely, younger fit and anxious patients may need a larger dose. It should be injected into a running intravenous line in a larger vein to limit the pain on injection, and because the emulsion supports microbial growth, ampoules are drawn up with strict asepsis and used promptly, with any unused drug discarded. It is safe in porphyria, an advantage over thiopentone, and its lack of analgesic action means an opioid or regional technique must supply the analgesic component of the anaesthetic.

Marked hypotension and apnoea — titrate in the elderly.

• Propofol: commonest IV induction agent; lipid emulsion; GABA_A; dose 1.5–2.5 mg/kg.
• Rapid clear recovery + anti-emetic + infusible → ideal for day surgery & TIVA/TCI.
• Adverse: hypotension, apnoea, pain on injection; NO analgesia.
• Lipid emulsion supports bacterial growth — strict asepsis.
• Rare propofol infusion syndrome with prolonged high-dose infusion.