Local Anesthetics

Front 1

la moa

Back 1

block na conduction into cell (several contiguous channels to overcome reserve), does not affect cell fxn or k influx, conc dep, reversible, prefers small/unmyelinated fibers
(sensory, autonomic)

higher pka: cationic form dominates, delayed onset

potency depends on lipid sol

inc pro binding: longer duration, less tox (less free drug)

absorption based on vascularity: iv>intercostal>caudal>epidural>brachial plexus>sciatic/femoral

Front 2

ester la

Back 2

hepatic metab pseudocholinesterase, rbc esterase, one "i" in name, cocain, procaine, tetracaine, 2-chloroprocaine, benzocaine

Front 3

la tox

Back 3

cns:
initially: lightheadedness, perioral numbness, tinnitus, dizziness, disorientation, drowsiness
high dose: excite --> dep, muscle twitching, convulsions, unconsciousness, coma, resp dep/arrest, cv dep/collapse

cardiac: dep, dysrhythmia (esp bupivacaine), hypotension

periph: low dose vasoconstrict, high dose vasodilate (sns block)

methb w/ prilocaine, benzocaine, m necrosis, allergix rxn (esters/old amides --> para amino benzoid acid)

Front 4

amide la

Back 4

hepatic metab cyp450, two "i"s in name, lidocaine, dibucaine, mepivacaine, bupivacaine, ropivacaine, prilocaine

Front 5

cocaine

Back 5

natural, local vasoconstriction (block reuptake catecholamines in sns n term), local neural tox, potential for abuse, short duration, topical (nasomucosal)

Front 6

procaine

Back 6

novocaine, first injectable, metab in plasma by pseudocholinesterase (from liver), renal excrete, very short duration

Front 7

tetracaine

Back 7

slow onset (high pka), very long duration, excellent topical, 100 mg max dose, use spinal, potent, highest ae risk

Front 8

2-chloroprocaine

Back 8

safest ester, high pka but fast onset due to high conc, 45-60 min, rapid term effect, iv cause thrombophlebitis

Front 9

benzocaine

Back 9

benzoic acid derivative, only high conc effective, very long duration, mostly mucous membranes, topical/spray

ae methb

Front 10

lidocaine

Back 10

xylocaine, liver metab (p450), renal excrete, medium duration (few hrs), most rapid onset, most popular, potent, anti-arrhythmic

Front 11

dibucaine

Back 11

most potent, high tox (no iv), metab p450 but inh plasma cholinesterase, only for topical use in cream

Front 12

mepivacaine

Back 12

similar to lidocaine but less vasodilation, greater potency/duration, useful epidural/spinal/periph n block, potential for accumulation (use only short term), rapid onset, medium-long duration, drug of choice for infiltration/pnb, toxic to fetus

Front 13

bupivacaine

Back 13

greater potency/duration (highly liposoluble) than lidocaine but slower onset (high pka), good for spinal anesthesia anesthesia as iso/hyperbaric sol (hyperbaric dense so settles down, less chance to affect high spinal like cardiac sns), epi doesn't add to duration, significant fq-dep block, cardiac tox w/ high systemic blood levels (d-isomer), use low conc for vaginal delivery (don't want m block), high conc for c-section (need m block)

Front 14

ropivacaine

Back 14

almost pure s-isomer of bupivacaine (less cardiac tox), less potent/lasting, better fq-dep block, less motor more sensory block, long duration, doc for epidural, use ob, pnb, infiltration

Front 15

prilocaine

Back 15

most rapidly metabolized, ortho-toluidine ring --> methb, usu use pnb for dentistry, less vasodilation, lower cns tox, don't use ob

Front 16

etidocaine

Back 16

very long duration, usu use epidural, keeps lower extremities still, preferential motor block

Front 17

la adjuvants

Back 17

epi: 1:200k, dec abs, prolong duration

bicarb: inc ph of sol, accelerate onset since mor nonionized, may dec duration, can precipitate ropivacainee/bupivacaine, good for urgent c-section (w/in 5-10 min)