<prompt> Local anesthetic that can cause MethemoglobinemiaRopivacainePrilocaineAmethocaineBupivacaine  <response>: Ans. b Prilocaine Ref. KDT 5th ed., 325; Anaesthsia by Ajay Yadav 3rd ed., 218-appendix; 114Local anesthetic is associated with the risk of Methemoglobinemia- Prilocaine.PRILOCAINE Prilocaine is an amide type local anesthetic agent. Safest Local Anesthetic Metabolized in liver, kidney and lung Maximum safest dose is 5 mgkg with adrenaline 8 mgkg Most suitable for Biers block 0.5 Methemoglobinemia occurs at higher dose prilocaine is unique amongst the local anesthetic agents for its ability to reduce the bloods oxygen carrying capacity to cause clinically detectable cyanosis. Stored in cool place Metabolized by pseudocholine esterase Agent of choice in patients with history of malignant hyperthermia. It is the first synthetic local anesthetic introduced in 1905. Practically, it is not used today. Prilocaine can however be used for Biers block or intravenous regional anaesthesia--IVRA. No serious complications have been documented. Equipotent with lignocaine, but its duration of action is longer and it is less toxic. It is not a surface anesthetic.Chart 1: Drug capable of inducing methemoglobinemia AcetaminophenAnti malaria drugsNitratesNitric oxidep-Aminislicylic acidChloroquineAmmonum nitrateNitrous oxideLocal anestheticsPrimaquineSilver nitratePiperazineBenzocaineQuinacrineSodium nitrateRifampinBupivacaineMethylene blueNitroglycerineRiluzoleLidocaineDapsoneNitroprussideSulfonamidesPolocainePhenacetinsBismuth subnitrateSulfasalazineEMLAPhenazopyndineNitntesSulfamethoxazoleAnticonvusantsFlutamideAmyl nitrateSulfadiazineVaiproic acidHydroxylamineIsobutyl nitrateSulfapyridinePhenytoinOral hypoglycemicMetochlopramideNitrofurantoinSulfonesSulfanilamide 