Study: CBD Shows Potential as Long-Lasting Local Anesthetic

A new study published in Anesthesia & Analgesia suggests cannabidiol may have potential as a long-lasting local anesthetic or as an add-on to existing anesthetics.

The study, conducted by researchers at Hannover Medical School, examined how CBD affects voltage-gated sodium channels, known as Nav channels. These channels play a key role in the transmission of pain signals, and they are the same general target of widely used local anesthetics such as lidocaine.

Researchers used patch clamp recordings to evaluate CBD’s effects on tetrodotoxin-sensitive sodium channels and the tetrodotoxin-resistant Nav1.8 channel in cell models and murine dorsal root ganglion neurons. They also assessed cytotoxicity using flow cytometry.

The study found that CBD produced strong tonic inhibition of sodium currents, with both slow onset and slow offset kinetics. Researchers said this slow binding profile may be especially relevant for regional anesthesia, where a longer-lasting effect could be beneficial.

CBD appeared to be particularly active against Nav1.8, with an IC50 of 1.4 µM compared with 2.9 µM for tetrodotoxin-sensitive sodium channels. The compound also shifted steady-state inactivation and produced a modest use-dependent block at 10 Hz, effects that resemble some features of local anesthetics.

However, the researchers found important differences between CBD and standard local anesthetics. Unlike lidocaine and similar drugs, CBD’s inhibition of sodium channels was not dependent on pH.

When CBD was combined with lidocaine, the two produced an additive tonic block of sodium currents in ND7/23 cells, but not in dorsal root ganglion neurons. The safety findings were mixed: high concentrations of CBD alone caused cytotoxicity, and CBD also increased lidocaine-induced cytotoxicity.

Researchers concluded that CBD has “promising characteristics” as a long-lasting local anesthetic or as an adjunct for regional or topical anesthesia, but the toxicity findings suggest more research is needed before any clinical application.