How long does lidocaine usually last?

1/2 to 1 1/2 hours. Depending on where the Lidocaine is placed, the relative blood flow and the ph level of the tissues can affect how long Lidocaine lasts. It may be necessary to mix Lidocaine with other agents such as Epinephrine which help keep the Lidocaine in the tissue. Mixing it with long acting agents such as Marcaine can also lengthen the time that Lidocaine lasts.