Which of the following local anaesthetic should not be alkalinized with soda bicarbonate: (A) Lignocaine, (B) Procaine, (C) Bupivacaine, (D) Benzocaine
Answer is C. Local anaesthetic drug if dissociated –it wont act on sodium channel.
So drug is kept undissociated by adding soda bicarbonate to maintain pka 7.7→ 8.2
But for bupivacaine soda bicarbonate is not used as it gets precipitated.