propofol
Meaning of propofol: Speed is the whole point: it takes effect within a breath or two and lets go just as fast, and it provides no pain relief.
Definition of propofol
Propofol is a short-acting anesthetic given into a vein to produce sedation or general anesthesia. It works within seconds and wears off almost as quickly once stopped, which suits it to starting anesthesia, maintaining it by continuous infusion, and sedating people during procedures. It is a milky white emulsion, because the drug itself does not dissolve in water.
How does it work, and why so fast?
Propofol strengthens the action of GABA at its receptor, the main inhibitory switch in the brain, so nerve cells become much harder to fire. Its speed has nothing to do with how tightly it binds and everything to do with fat solubility: injected into a vein it crosses into the brain within one circulation time, and it then leaves the brain just as readily, spreading into muscle and fat long before the liver has finished breaking it down. Recovery therefore comes from the drug moving away rather than from it being destroyed, which is why waking after anesthesia with propofol tends to be quick and comparatively clear-headed.
How does it compare with other agents?
| Agent | Character |
|---|---|
| Propofol | Fast on and off, no pain relief, lowers blood pressure, suppresses breathing, reduces nausea |
| Midazolam | Slower on and off, strong amnesia, less effect on blood pressure |
| Ketamine | Provides pain relief and preserves breathing and blood pressure better, but can cause vivid emergence experiences |
| Etomidate | Very stable blood pressure, but suppresses adrenal steroid production |
An anesthetic is chosen from this range according to the procedure and the person, and propofol is frequently paired with an opioid or a local anesthetic precisely because it does nothing for pain.
What effects require close monitoring?
Two dominate. It relaxes blood vessels and reduces the force of each heartbeat, so blood pressure falls in a dose-related way, more steeply in someone already depleted of fluid. And it suppresses the drive to breathe, with airway obstruction or a pause in breathing possible even at sedative doses, which is why it is given by someone able to support the airway and with monitoring in place throughout. Pain at the injection site is common. The lipid emulsion supports bacterial growth, so strict handling rules apply and opened vials are discarded. Prolonged infusion at high dose is associated with a rare but serious syndrome involving acid build-up, muscle breakdown and cardiac failure.
Also known as
Used in a sentence
Propofol was administered to induce anesthesia prior to the procedure.
Good to know
Propofol has a short duration of action compared with many other sedating agents and provides no pain relief, two properties that shape how it is combined with other drugs and used for procedures of different lengths.