[Verse 1] Sodium channels sitting in the membrane wall A local anesthetic comes to block the hall Uncharged form diffuses through the lipid gate Then ionized inside — that's how we seal your fate Potency tied to lipid solubility high Protein binding holds the duration, watch it climb Onset governed by pKa — the lower wins the race More un-ionized at body pH, faster to the place [Chorus] Chloro, lido, mepivacaine Ropi, levo, bupivacaine Esters cleave in plasma, amides through the liver chain Max dose, LAST response, lipid emulsion on the brain Three percent chloroprocaine — fastest one to call Bupivacaine — longest acting, heaviest baricity of all [Verse 2] Esters carry para-amino, allergic risk is real Amides got that second "i" in name — the trick to seal Add epinephrine, vasoconstrict, prolong and contain But never on a digit, never near a ring-shaped vein Bicarbonate accelerates onset, raises pH fast Clonidine extends the sensory block designed to last Liposomal bupivacaine — slow release, extended window wide Seventy-two hours of post-op cover wrapped inside [Chorus] Chloro, lido, mepivacaine Ropi, levo, bupivacaine Esters cleave in plasma, amides through the liver chain Max dose, LAST response, lipid emulsion on the brain Three percent chloroprocaine — fastest one to call Bupivacaine — longest acting, heaviest baricity of all [Verse 3] LAST comes in stages — metallic tongue and ringing ears Circumoral numbness, then the CNS appears Seizures first, then cardiovascular collapse descends Bupivacaine the worst — it wedges deep where sodium ends Call for help and stop the drug, secure that airway fast Twenty percent lipid emulsion — fifteen mils per kilo mass One point five per kilo bolus, then the infusion runs ASRA checklist in your pocket, prop-o-fol is shunned [Bridge] Intrathecal baricity — hypo, iso, hyper three Heavy bupivacaine sinks down with gravity Position the patient, tilt the table, watch where it goes Lidocaine spinal — transient neurologic symptoms show Burning down the buttocks, shooting bilateral thighs TNS resolves, but cauda equina never fully dies High concentration, pooling drug, the roots begin to scar Keep your doses calibrated — know exactly where you are [Chorus] Chloro, lido, mepivacaine Ropi, levo, bupivacaine Esters cleave in plasma, amides through the liver chain Max dose, LAST response, lipid emulsion on the brain Three percent chloroprocaine — fastest one to call Bupivacaine — longest acting, heaviest baricity of all [Outro] Ropivacaine — less cardiotoxic, S-enantiomer pure Levobupivacaine follows close behind that door Mepivacaine — medium duration, vasoconstricts alone Six agents mapped across your practice, carved in bone Block the channel, read the signs, and keep that lipid near Anesthesiology foundations — crystal clear
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