Maximum dose of lignocaine with adrenaline is (in mg/ kg)

Ans. c (7). (Ref. Harrisons Medicine, 18th/735)LIGNOCAINE# Maximum safest dose 3 mg/kg or 200 mg and with adrenaline 7 mg/kg or 500 mg.# Duration of effect 45 to 60 min and with adrenaline it is 2-3 hours.# Should not be given in patients with history of malignant hyperthermia.# Concentration usedo Surface topical analgesia- 4%o As jelly, for urethra- 2%o Nerve blocks/epidural/infiltration block-- 1-2%o Spinal- 5%# Lignocaine is an amide# It is 4 times less potent than bupivacaine# Drug of choice for lignocaine-induced arrhythmia is bretylium tosylate (SGPGI 2002)# Repeated doses of 4-5 mL of 0.5% bupivacaine or 1% lignocaine are used to maintain epidural analgesia.# 'Transient neurological symptoms' is an disntinct side-effect of LignocaineEducational point:The baricity of the local anesthetic solution. Baricity is defined by the ratio of the density of the local anesthetic solution to the density of CSF. A solution with a ratio > 1 is hyperbaric and tends to sink with gravity within the CSF. An isobaric solution has a baricity of 1 and tends to remain in the immediate area of injection. A ratio < 1 is a hypobaric solution, which rises in the CSF.