-
benzocaine
- ester-type, short acting, topical
- blockage of voltage-dependent Na+ channels
- SE: allergic rxns (PABA metabolite), methemoglobinemia
-
cocaine
- ester-type local anesthetic
- topical anesthesia & vasoconstriction in nose, throat, oral cavity
- blockage of voltage-dependent Na+ channels
- blocks NE reuptake (vasoconstriction effect)
-
lidocaine
- amide-type local anesthetic
- moderate duration (1-2h)
- blocks voltage-dependent Na+ channels
- SE: effects related to systemic absorption, mood changes, nausea, drowsiness, vision changes, headache
-
bupivacaine
- amide-type local anesthetic
- oral, obstetrical surgery
- longer duration of action (6-8h)
- blocks voltage-dependent Na+ channels
- SE: cardiotoxic, usually only in systemic exposure
-
ropivacaine
- amide local anesthetic
- long-acting (2-6h)
- slightly less potent, but less SE than buvivacaine
- blocks voltage-dependent Na+ channels
-
EMLA
- topical anesthetic
- Eutectic mixture of local anesthetics - lidocaine and prilocaine
- SE: skin rxns
-
topiramate
- oral anticonvulsant (for epilepsy), neuropathic pain
- modulation of Na+ channels, potentiation of GABA inhibition, blockage of glutamate, modulation of Ca++ channels
- SE: somnolence, nausea, weight loss, numbness
-
amitripyline
- TCA, neuropathic pain med
- postherpetic neuralgia, diabetic neuropathy
- NE and 5HT reuptake inhibitor, Na+ channel blocker, NMDA antagonist
- SE: anticholinergic effects (blurred vision, constipation, dry mouth, sedation, tachycardia, urinary retention, delirium in older pts) - worse w/tertiary form of the drug
-
gabapentin
- oral anticonvulsant, neuropathic pain med
- diabetic neuropathy, postherpetic neuralgia
- reduces current in Ca++ channel
- highly lipid soluble, not metabolized, no SE!
-
pregabalin
similar to gabapentin, but more potent, greater bioavailability
-
capsaicin
- depletion of substance P from sensory neurons, nociceptor desensitization
- topical analgesic, burning on initial application, low compliance
-
Baclofen
- central-acting w/o direct effect on skeletal muscle
- GABA B receptors - hyperpolarization
- SE: drowsiness, nausea/vomiting
- withdrawal syndrome
-
carisoprodol
- GABA A agonist
- central-acting
- less frequently used
-
cyclobenzaprine
structurally related to TCA but not used as an antidepressant
-
lidocaine systemic effects
- seizures
- cardiovascular collapse
- death
-
onset of nerve blockade in infected tissues
slower
-
mech of action of local anesthetics
- weak bases; neutral form diffuses through PM
- protonated form blocks Na+ channel
- preferentially binds to more activated channels
- small C unmyelinated fibers are affected before large A-beta fibers, higher SA
-
amide v. ester metabolism
- amide: hepatic metabolism, longer half-life, allergic rxns rare
- esters: plasma cholinesterases, rapid degradation, shorter half life, PABA metabolite (allergy)
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