When the acidity of the tissue increases,as in instances of infection,the effect of a local anesthetic decreases;therefore,the local anesthetic is a weak acid.

Question

Quizplus · Accepted Answer

The first part of the statement is true,the second part is false.Infections lead to an accumulation of acidic waste products,which lowers the pH of the local area.Local anesthetics must penetrate the nerve cell membrane to cause their action.They become more ionized as the pH drops.This property is a characteristic of weak bases,not weak acids.Local anesthetics are weak bases.Weak bases are better absorbed when the pH is greater than the pKa.A weak base is associated and ionized when the pH is less than the pKa.

When the Acidity of the Tissue Increases,as in Instances of Infection,the