Review Question - QID 106250

This patient is undergoing a laceration repair and needs a local anesthetic. Bupivacaine mixed with epinephrine will offer the longest duration of pain control.

Lidocaine is a local anesthetic and antiarrhythmic drug. It is used topically for pruritis, burning, and pain of the skin or as a local anesthetic for minor surgery. It functions by blocking voltage-gated sodium channels preventing pain sensation. Bupivacaine acts similarly to lidocaine except it takes longer for this medication to take effect and it has a longer duration of action. Both of these drugs are appropriate local anesthetics for procedures. Mixing either of these agents with epinephrine can prolong the duration of anesthesia and reduce the dose needed (since epinephrine causes vasoconstriction thus keeping the anesthetic local). Generally, the pain relief from lidocaine is roughly 1-2 hours but only takes a few minutes to take effect; whereas, the pain relief from bupivacaine lasts 4 to 8 hours but takes up to 15 minutes to take effect.

Incorrect Answers:
Answer 1: Bupivacaine without epinephrine would not offer the longest local anesthesia when compared to the addition of epinephrine which keeps the agent local longer for better pain control.

Answers 3 & 5: Lidocaine has a faster onset than bupivacaine and a shorter half-life thus it would not offer the longest pain control (though it would control pain more rapidly).

Answer 4: Lidocaine mixed with bupivacaine could be given to offer both fast pain control (lidocaine) and long pain control (bupivacaine) but would not last as long as bupivacaine by itself with epinephrine.

Bullet Summary:
Lidocaine is a local anesthetic with a fast onset of anesthesia and bupivacaine is a local anesthetic with a long duration of action.