In: Anesthesia12 Jan 2010
Propofol (2,6-diisopropylphenol) is a sterically hindered alkyl phenol derivative that is structurally unrelated to other sedative hypnotic agents. Since its introduction in 1985, propofol has proven to be useful in numerous clinical situations. Examples for the application of propofol include cardiovascular, ophthalmologic, and neurosurgical procedures as well as a variety of outpatient surgeries. Propofol has also been utilized for sedation, electroconvulsive therapy, cardioversion, tracheal intubation, mechanical ventilation, status epilepticus, tetanus, and as an antiemetic and antipruritic.
In the dental setting, propofol is widely used in outpatient oral and maxillofacial surgery. Several studies have demonstrated propofol’s safety and efficacy in children, and the drug is often employed as an adjunct in dissociative sedation to speed the recovery of the pediatric dental patient. canadian drugstore online
The most notable advantages for the use of propofol in outpatient surgical procedures include the minimal side effects, controllable anesthetic state, quick onset, rapid emergence from general anesthesia, and rapid recovery of psychomotor and cognitive function.
Propofol exhibits first-order pharmacokinetics with a 3-compartment linear model. There is a quick distribution from the blood into the tissues, a rapid metabolic clearance from the blood, and a slow release of the drug from the deep peripheral compartments into the blood. The lipophilicity of propofol allows for the blood-brain barrier to be easily breached. Following the rapid equilibration between the plasma and the highly vascularized tissue of the brain, a quick redistribution of the drug to peripheral tissues provides a fast onset but short duration of action. High metabolic clearance also contributes to the plasma level diminution following propofol delivery. The effects of anesthesia are seen within 1 arm-brain circulation time (about 40-50 seconds after administration). There is a range of infusion rates capable of maintaining anesthesia over a number of hours at very high volumes of distribution, 3.5-4.5 LAg. This distribution decreases over time as bodily tissues equilibrate with plasma (the transfer between tissues and blood equalizes). The elimination half-life of 3-12 hours, Ј1/2-8, is due to the slow return of propofol from the deep compartment (probably adipose tissue) and is the rate-limiting factor of elimination. T1/2-a, the rapid distribution half-life of 2-4 minutes, is attributed to the distribution from the blood into tissues. Finally, the slower distribution half-life of 30-64 minutes, t1/2-fi, represents the metabolic clearance from blood. cialis professional
The liver is the most important site of elimination, with a reported clearance of 70-140 L/h. In the liver, propofol is metabolized into 4 inactive metabolites—1-quinol glucuronide, 4-quinol glucuronide, propofol glu-curonide, and 4-quinol sulfate—and is eliminated in the urine. Gender, hepatic cirrhosis, and renal failure have no significant effect on propofol pharmacokinetics. With increasing age, the induction and maintenance dose requirements of the drug are lowered. Propofol pharmacokinetics are also altered by coadministration of other drugs. Cockshott et al found blood propofol levels to be 50% higher, after induction, in patients receiving 2 imgAg of fentanyl.
Blog invites submissions of review articles, reports on clinical techniques, case reports, conference summaries, and articles of opinion pertinent to the control of pain and anxiety in dentistry.