Intravenous anesthetics

Given IV, these drugs reach the brain fast and switch off consciousness, so they are used to start (induce) anesthesia and for sedation; propofol works within about 40 seconds. Their targets differ: propofol enhances inhibitory GABA-A receptor signaling, while ketamine blocks excitatory NMDA glutamate receptors. As with all general anesthetics, how they cause unconsciousness is not fully understood.

• PropofolQuick on and quick off: unconsciousness within about 40 seconds and prompt waking after short use. Unlike ketamine, it lowers blood pressure and often causes apnea at induction.
• KetamineUnlike propofol, it tends to keep up blood pressure and breathing and gives strong analgesia, but emergence reactions and misuse limit it; it is a controlled drug.

• Inducing and maintaining general anesthesia
• Sedation for procedures and ventilated ICU patients

• Low blood pressure (propofol)Known for
• Apnea and breathing depressionKnown forSerious
• Emergence delirium and vivid dreams (ketamine)Known for
• Slow heart rate (propofol)Serious
• Raised blood pressure and heart rate (ketamine)
• Pain at the injection site
• Laryngospasm and airway obstructionSerious
• AnaphylaxisSerious
• Nausea and vomiting
• Propofol infusion syndrome with long ICU infusionsSerious

What the class has in common. Each drug's card has its own, and Known for marks what an exam expects you to know.

• Give only where the airway can be managed and breathing supported: apnea is common at induction.
• Opioids, benzodiazepines and other CNS depressants deepen sedation and breathing depression.
• Long or repeated anesthesia (over 3 hours) in children under 3, or late in pregnancy, may affect brain development.
• Propofol is avoided after anaphylaxis to egg or soy; ketamine where a rise in blood pressure would be dangerous.

Written for biofideX in plain words, after checking these references:

• Propofol injectable emulsion: label (DailyMed)
• Ketamine hydrochloride injection: label (DailyMed)
• Propofol (NCI Thesaurus)
• Ketamine (NCI Thesaurus)

For learning pharmacology, not for treatment decisions: no doses are given, and a prescriber, pharmacist or the product's own label is the word on any one patient. Spotted a mistake? Tell us and we'll correct it.