New Local Anesthetic Is Derived From Algae

An innovative long-acting local anesthetic derived from algae shows significantly less postoperative pain and earlier recovery than the commonly used local anesthetic bupivacaine.

Neosaxitoxin (neoSTX) is a phycotoxin (neurotoxin) naturally produced by certain species of marine dinoflagellates and cyanobacteria that serves as a site-1 sodium-channel blocker, reversibly blocking the voltage-gated sodium channels at neuronal level. It is part of larger class of emerging anesthetics--based on molecules derived from aquatic organisms--in which the anesthetic activity is expressed as blocking the axonal conduction, stopping the propagation of the nerve impulse. The term originates from the species name of the butter clam (Saxidomus giganteus), in which it was first recognized.

The neoSTX trial, held by researchers at Padre Hurtado Hospital (Santiago, Chile), Children's Hospital Boston (MA, USA), and start-up company Proteus SA (Santiago, Chile) involved 137 Chilean patients who underwent laparoscopic removal of their gall bladders. The results of the study showed that fewer of the patients randomized to neoSTX group reported severe postoperative pain at the incision site. Significantly, more neoSTX-treated patients had complete absence of pain at 12 hours, both at rest and with movement. Patients in the neoSTX group also reported a full functional recovery approximately two days earlier; no serious adverse reactions occurred in either group. The study was published in the March-April 2011 issue of Regional Anesthesia and Pain Medicine.

"In my opinion, there has not been a truly innovative new local anesthetic medication in the last 40 to 50 years,” said study coauthor Charles Berde, MD, PhD, chief of the division of pain medicine at Children's Hospital Boston. "Most drugs introduced over that time period have represented only minimal advances. There have been candidate drugs that went in novel directions, but they've had shortcomings, and none have made it to market.”

neoSTX is not addictive, has no cardiac toxicity, and does not cross the blood-brain barrier (BBB), thus avoiding the risk of seizures occasionally seen with existing local anesthetics. It also causes minimal local tissue reaction, thus avoiding the nerve and muscle damage seen with high concentrations of existing local anesthetics.

Related Links:
Padre Hurtado Hospital
Children's Hospital Boston