Which statement about ketamine is FALSE?

Which statement about ketamine is FALSE?

• A. It is a racemic mixture of two isomers
• B. It is a potent cerebral vasodilator and can increase intracranial pressure
• C. Respiratory depression rarely occurs with induction doses
• D. Its metabolite norketamine is more potent than the parent compound

Answer: (D)

Ketamine’s pharmacology includes several distinctive features: it is administered as a racemic mixture of two enantiomers, which contributes to its dissociative anesthesia profile. It acts as a cerebral vasodilator, increasing cerebral blood flow, and this can raise intracranial pressure, so it’s used with caution in patients with brain injury or elevated ICP. Unlike many anesthetics, it tends to preserve spontaneous breathing and airway reflexes, so induction doses rarely cause significant respiratory depression, though issues like increased secretions or occasional laryngospasm can occur. Metabolically, ketamine is demethylated to norketamine, which is pharmacologically active but less potent than ketamine itself, and it contributes to a longer duration of effect rather than being more potent. Therefore, the statement that norketamine is more potent than the parent compound is false.

Ketamine’s pharmacology includes several distinctive features: it is administered as a racemic mixture of two enantiomers, which contributes to its dissociative anesthesia profile. It acts as a cerebral vasodilator, increasing cerebral blood flow, and this can raise intracranial pressure, so it’s used with caution in patients with brain injury or elevated ICP. Unlike many anesthetics, it tends to preserve spontaneous breathing and airway reflexes, so induction doses rarely cause significant respiratory depression, though issues like increased secretions or occasional laryngospasm can occur. Metabolically, ketamine is demethylated to norketamine, which is pharmacologically active but less potent than ketamine itself, and it contributes to a longer duration of effect rather than being more potent. Therefore, the statement that norketamine is more potent than the parent compound is false.