Isobolographic analysis reveals antinociceptive synergism between Phα1β recombinant toxin and morphine in a model of cancer pain in C57BL/6J mice.

Background: venom contains Phα1β. This toxin and its recombinant form have a remarkable analgesic potential that is associated with blockage of voltage-gated calcium channels and TRPA1 receptors. Although morphine is a mainstay drug to treat moderate and severe pain related to cancer, it has serious and dose-limiting side effects.

Antinociceptive synergism upon the joint use of methadone and Phα1β in a model of cancer-related pain in C57BL/6J mice.

Unlabelled: Opioids are the first-line treatment for cancer pain. Incomplete pain relief and the high rate of adverse effects of these compounds bring a need to combine them with other drugs acting on different targets.

Aims: We here evaluate the antinociceptive interaction and adverse events of methadone combined with recombinant Phα1β, an analgesic toxin from Phoneutria nigriventer.