All Local anesthetics contain suffix “-caine”. Local Anesthetics (LA) can be classified as: Esters and Amides.
Esters vs Amides
A mnemonic device is that the names of amides contain 2 “i”s compared with only 1 “i” seen in esters.
Remember: One-eyed ester or Amide word has an “i” in it and hence an extra “i”.
Amides – Contains 2 “i”
Properties:
- Longer acting than esters
- Metabolized by liver enzymes
- Excreted in urine
Medicines:
- Lignocaine
- Lidocaine (Xylocaine)
- Prilocaine
- Mepivacaine
- Bupivacaine (Marcaine/Sensoricaine)
- Etidocaine
- Ropivacaine
- Dibucaine
- Articaine
- Trimecaine
- Dexivacaine
- Butanilacaine
Exceptions:
Amides with only single “i” are –
- Oxetacaine
- Tolycaine
- Pyrrocaine
- Rodocaine
Amide without suffix “caine” – Diperodon
Esters – Contains single “i”
Properties:
- Short acting
- Metabolized in plasma and tissue fluids
- Excreted in urine
- More propensity for allergic reactions
Medicines:
- Amethocaine
- Benzocaine
- Chlorprocaine
- Procaine (Novocaine)
- Cocaine
- Hexylcaine
- Proparacaine
- Tetracaine
Exceptions:
Ester with double “i” –
- Primacaine
- Piperocaine
- Dimethocaine
Ester without suffix “-caine” –
- Butamben
- Butethamine
- Naepaine
Rate of systemic absorption of Local Anesthetics
Mnemonic: In descending order – ICE BALLS
- Intravenous > Tracheal > Intercostal
- Caudal
- Epidural
- Brachial plexus
- Axillary
- Lower extremity (femoral)
- Subcutaneous
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He is the section editor of Orthopedics in Epomedicine. He searches for and share simpler ways to make complicated medical topics simple. He also loves writing poetry, listening and playing music.