Buffering May Increase Efficacy of Low-Dose Anesthetic Agents

A study published in the October Journal of Oral and Maxillofacial Surgery, “Buffered 1% Lidocaine With Epinephrine Can Be as Effective as Nonbuffered 2% Lidocaine With Epinephrine for Maxillary Field Block,” reports that by changing the formulation’s acidity, a lower dose of lidocaine can be as effective as a higher dose of the local anesthetic.

Researchers compared buffered 1% lidocaine with nonbuffered 2% lidocaine in 24 adult subjects (median age 23.5 years) tested at the University of North Carolina Oral and Maxillofacial Surgery Clinic. Subjects were evaluated with the alternate drug combinations (buffered and nonbuffered) two weeks apart. Teeth were evaluated using pulpal response to cold and electric pulp testing on the maxillary first molar and canine at 30-minute intervals until a baseline response was detected. Participant pain levels during the injection, as well as the time it took to numb the midface area, were also recorded.

Among the subjects, 58% reported less pain after receiving buffered 1% lidocaine than nonbuffered 2% lidocaine — but no matter the drug formulation, the subjects’ reported pain levels overall were low (averaging four on a 10-point scale). In addition, 58% of participants also reported a shorter time to midface numbness after receiving buffered 1% lidocaine than nonbuffered 2% lidocaine — although researchers note the difference between the two drugs was insignificant.

These findings may lead to further studies, especially in light of the fact that specific groups of patients could benefit from reduced drug dosages. According to the researchers, this includes pediatric patients, “whose lidocaine drug dosages and treatment are now limited by caution not to exceed maximum blood lidocaine levels, based on body weight.”