12 - Red Flashcards
1
Q
What drug class do most local anesthetic belong in
A
Amides
2
Q
What is the max dosing of lidocaine / xylocaine
A
NO epi - 5ml/kg
EPI - 7ml/kg
1% = 1g/100cc = 10 mg/cc
Quick rule
1% no epi = wt/2
2% no epi = wt/4
+EPI = x1.4
3
Q
What is the mechanism of action of amide local anesthetics
A
Bind to Na+ channel on the cytotoxic side an prevent Na+ influx
4
Q
What is the metabolism of local anesthetics
A
Hepatic, excreted in urine
5
Q
What is the onset and duration of action for various local anesthetics
A
Amides: Drug / duration in hrs / comments Lidocaine: 1 her , fast onset Bupivicaine: 4-12 hr , slow onset, long effect and exaggerated cardiotoxicity Ropivicaine: 4-12 hrs, less cardiotoxic
Esters:
Tetracaine: 10 hrs, slow onset
6
Q
What are the CNS toxicities from local anesthetics
A
Numb tongue, peri-oral tingling Disorientation Tinnitus Visual disturbances Muscle twitching Convulsions, seizures Generalized CNS depression -> coma -> resp arrest
7
Q
What are the CVS toxicities from local anesthetics
A
Vasodilation, hypotension Increased myocardial contractility Dose-dependent delay of cardiac impulse transmission Prolonged QRS, PR intervals Sinus Brady, asystole CVS collapse
8
Q
What is the treatment for local anesthetic toxicity
A
ABC
Epi for cardiac collapse
Diazepam, thiopental, succinylcholine
