Chapter 21

Local anesthetics exert their effects by which one of the following mechanisms? (A) increasing \(\mathrm{K}^{+}\)conductance and hyperpolarizing nerves (B) blocking the \(\mathrm{Na}^{+}\)channels in nerves (C) inactivating the \(\mathrm{Na}^{+}, \mathrm{K}^{+}\)-adenosine triphosphatase (ATPase) pump (D) blocking excitation at postsynaptic receptors (E) blocking by a direct action only at the synapse

Epinephrine is sometimes added to commercial local anesthetic solutions for which purpose? (A) to decrease the rate of absorption of the local anesthetic (B) to decrease the duration of action of the local anesthetic (C) to block the metabolism of ester-type local anesthetics (D) to enhance the distribution of the local anesthetic (E) to act synergistically with the local anesthetic at the nerve ion channel

Which of the following characteristics is used to quantitate and compare the potency of gaseous general anesthetics? (A) blood:gas partition coefficient (B) minimal alveolar concentration (C) blood:brain partition coefficient (D) rate of uptake and elimination (E) relative analgesic potency

Which one of the following inhalational anesthetics can provide anesthetic effectiveness only under hyperbaric conditions? (A) enflurane (B) nitrous oxide (C) halothane (D) methoxyflurane (E) isoflurane

Muscle rigidity can be a side effect of which intravenous anesthetic? (A) fentanyl (B) midazolam (C) ketamine (D) propofol (E) thiopental