Propofol

 Propofol

REF: Morgan’s clinical anesthesiology 3′ edition page 173

Repeat in December 2010

“Propofol is the most suitable intravenous induction agent for day care surgery”

Propofol

Propofol

Propofol

It is the induction agent of choice in day care surgery.

The half life is 100 minutes, but the clinical effects of a single dose of propofol lasts only for 10 minutes due to its rapid redistribution.

It has minimal residual impairment, anti emetic and anti pruritic property, making it a suitable drug for day care surgery.

Ref: Essentials of Medical Pharmacology By KD Tripathi, 5th Edition, Page 343

Propofol has replaced the barbiturates for induction of anesthesia in the ambulatory setting because of its favorable recovery profile.

Recovery after induction of anesthesia with propofol is faster than with the barbiturate compounds and

 it is associated with low incidence of post operative nausea and vomiting.

Propofol is an oily liquid employed as emulsion for intravenous induction and short duration anaesthesia.

Patient become unconsciousness 15-45 seconds following administration of the drug and recovers in 10 minutes.

It is suitable for outpatient surgery because there is less residual impairment and low incidence of post operative nausea and vomiting.

Propofol can be used safely in porphyria.

Propofol is the recommended agent of choice for induction in susceptible individuals for malignant hyperthermia.

Smooth induction, rapid onset of action, easy titration to effect,

short clinical duration of action and demonstrable antiemetic effect make propofol an induction agent of choice for day care anaesthesia.

Ref: Lee’s Synopsis of Anesthesia, 13th Edition, Pages 158-60; Short Textbook of Anaesthesia By Ajay Yadav, 2nd Edition, Page 74 and 3rd Edition, Page 37; Handbook of Clinical Anesthesia By Paul G. Barash, Bruce F. Cullen, Robert K. Stoelting, M. Christine Stock , 6th Edition, Pages 257-259; Clinical Anesthesia By Paul G. Barash, Bruce F. Cullen, Robert K. Stoelting, Michael Cahalan, 6th Edition, Page 461

Propofol is the mostly used intravenous induction agent for day care surgery because of its early induction and

 less marked residual impairment.

It is associated with low incidence of postoperative nausea and vomiting.

Propofol is the most suitable intravenous induction agent for day care surgery,

because it is associated with a faster recovery and early return of psychomotor functions.

Propofol is primarily a hypnotic.

It acts by promoting the function of the b1 subunit of GABA through activation of the chloride channel and thereby enhancing inhibitory synaptic transmission.

Propofol also inhibits the NMDA subtype of glutamate receptor through modulation of channel gating.

This action may also contribute to the drug‘s CNS effects.

The hypnotic action of propofol is pressure reversible,

and it adheres to the correlation exhibited by other general anesthetics between anesthetic potency and octanol/water distribution coefficient.

Unlike barbiturates, propofol is not antianalgesic. Propofol at subhypnotic doses helps in the diagnosis and treatment of central, but not neuropathic, pain.

Propofol is an intravenous anaesthetic used as a 1% emulsion for iv induction and short duration anaesthesia.

It lacks airway irritancy and is particularly suitable for day care surgeries because of less residual impairment

and low incidence of postoperative nausea and vomiting.

Propofol is a sedative-hypnotic intravenous anesthetic agent.

It is the induction agent of choice in day care surgery. Properties include, 

• Early induction
• Smooth recovery
• Decreased incidence of post operative nausea and vomiting

Propofol is available only for intravenous administration for the induction of general anesthesia and for moderate to deep sedation.

• The high lipid solubility of propofol results in a fast onset of action.
• Because of its reasonably short elimination t1/2, propofol often is used for maintenance of anesthesia as well as for induction.
• Propofol is highly protein bound, and its pharmacokinetics may be affected by conditions that alter serum protein levels.
• The sedative and hypnotic actions of propofol are mediated by its action on GABAA receptors; agonism at these receptors results in an increased chloride conduction and hyperpolarization of neurons.
• Propofol is metabolized in the liver by conjugation to sulfate and glucuronide to less active metabolites that are renally excreted.

Ref: Patel P.M., Patel H.H., Roth D.M. (2011). Chapter 19. General Anesthetics and Therapeutic Gases. In L.L. Brunton, B.A. Chabner, B.C. Knollmann (Eds), Goodman & Gilman’s The Pharmacological Basis of Therapeutics, 12e.

Propofol has a rapid onset of action.

Awakening from a single bolus dose is also rapid due to a very short initial distribution half-life (2–8 min).

Most investigators believe that recovery from propofol is more rapid and is accompanied by less “hangover” than recovery from

methohexital, thiopental, ketamine, or etomidate.

This makes it a good agent for outpatient anesthesia.

Propofol’s shorter duration of action after infusion can be explained by

its very high clearance, coupled with the slow diffusion of drug from the peripheral to the central compartment.

Ref: Butterworth IV J.F., Mackey D.C., Wasnick J.D. (2013). Chapter 9. Intravenous Anesthetics. In J.F. Butterworth IV, D.C. Mackey, J.D. Wasnick (Eds), Morgan & Mikhail’s Clinical Anesthesiology, 5e.

Ans. is ‘c’ i.e., Propofol

“Propofol is particularly suitable for day care surgery because residual impairment is less marked and shorter lasting”.

Ans. is ‘b’ i.e., It causes severe vomiting

Propofol has anti-emetic action.

Ans. is ‘a’ i.e., Propofol

C i.e. Propofol

C i.e. Undergoes hepatic metabolism

D i.e. Cardiac stimulant

B i.e. It is contraindicated in porphyria

B i.e. Can be used in porphyria

A i.e. Etomidate; B i.e. Propofol

Increased infection and mortality in a group of patients sedated with etomidate infusion in an ICU was associated with low cortisol levelsQ and is attributed to etomidate induced supression of adrenal cortisal synthesisQ.

Etomidate is a dose dependent but reversible inhibitor of 11 – hydroxylase in the adrenal cortex and is more potent than metyrapone. This enzyme is required for both mineralocorticoid and corticosteroid production. Minor adrenocortical supressive effects (i.e. impaired response to ACTH) follow induction doses or short infusion doses.

Propofol is not recommended for sedation of critically ill pediatric patients in ICU. The drug has been associated with higher mortality d/t propofol infusion syndrome. Its essential features are metabolic acidosis, multiple organ failure, hemodynamic instability, hepatomegaly, and rhabdomyolysis. Very rarely, it may occur in adults, and in patients undergoing long term propofol infusion (> 48 hours) for sedation at high doses (>5 mg/ kg/ hr).

B i.e. Propofol

– Incidence of pain on injection after intravenous administration of drug in small vein (eg. dorsum of wrist or hand) is 80% for etomidate, 40% for propofol, 20% for methohexital 1% and 10% for thiopental 2.5% anesthetic agents

– This incidence is greatly reduced if a large vein is used, if a small dose of lidocaine (10mg) is injected shortly before.

Thiopental 2.5% also causes pain on IV administration but the incidence is much higher for propofol.

A i.e. Propofol, Fentanyl, isoflurane

C i.e. Propofol

B i.e. Day care surgery

D i.e. Propofol

Ans: C i.e. Contraindicated in porphyria

Propofol

• Side effects of propofol include pain on injection
• Propofol can be used for both induction as well as maintenance
• Propofol is safer in porphyria
• Propofol possess significant antiemetic action

Ans.: C: Propofol

Propofol is a short-acting, intravenously administered hypnotic agent.

Its uses include the induction and maintenance of general anaesthesia, sedation for mechanically ventilated adults, and procedural sedation.

Propofol is unrelated to barbiturates, and has largely replaced sodium thiopental (Pentothal) for induction of anaesthesia because recovery from propofol is more rapid and “clear” when compared with thiopental.

Propofol is not considered an analgesic, so opioids such as fentanyl may be combined with propofol to alleviate pain and it is the agent of choice for total intravenous anaesthesia (TIVA).

It is used to produce sedation in ICU.

It is the agent of choice for induction in susceptible individuals for malignant hyperthermia.

Due to its amnestic effects and appearance as a white liquid, propofol has been humorously dubbed “milk of amnesia”.

Ans. C: Propofol

Anaesthetics with anti-emetic property:

• Midazolam given at the onset of anaesthesia has been shown in to be as effective as ondansetron
• Propofol is versatile; the drug can be given for short or prolonged sedation as well as for general anaesthesia. It is an anti-emetic.

Ans. C: Propofol

Hence, it is recommended for longer-term sedation while midazolam is preferred for short-term sedation Propofol, another frequently used sedative agent, resembles midazolam in terms of pharmacological profile. Midazolam and propofol have similar efficacy and safety in sedating various groups of critically ill patients. Midazolam is, however, cheaper than propofol

Nevertheless, propofol, when used as a sedative in mechanically ventilated patients, is associated with shorter weaning times and hence, while midazolam may be cheaper, the overall cost-benefit analysis taking into account duration of mechanical ventilation and ICU stay may in fact be better with propofol.

Ans. B: Propofol

Infusions of subanaesthetic doses of propofol have been used to sedate patients for surgery under regional anaesthesia, and also to provide sedation of patients in intensive care.

Ans. a. Propofol

Any induction agents used in day-case anesthesia should ensure a smooth induction, good immediate recovery and a rapid return to street fitness. Propofol is now used widely as the primary induction agent, which has advantage of rapid recovery and low incidence of post-operative nausea and vomiting.’

Preferable agents in Day Care Anaesthesia

• Mivacurium^Q (muscle relaxant of choice, shortest duration of action)
• auccinylcholineQ (for Ultra short period of profound muscle relaxation; Disadvantage: Post-operative myalgia)
• Isoflurane^Q (volatile inhalational agent)
• AlfentanyIQ
• Propofol^Q (inducing agent of choice)
• Midazolam^Q (for initial anaxiolysis and sedation)
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