Verapamil potentiation of Chironex (box-jellyfish) antivenom.

'Rescue' experiments were performed on mice to compare the efficacy of i.v. verapamil, box-jellyfish antivenom, and a combination of both agents to counter the effects of toxic material extracted from the tentacles of Chironex fleckeri. In each of three series of experiments, four sets of mice were injected with doses of Chironex tentacle extracts containing approximately 4 mg/ml protein which were equivalent to twice the LD50. Three of these groups also received verapamil alone, antivenom alone, or a combination of both treatments. The combination therapy of drug and antivenom was superior to either agent alone. Treatment of verapamil alone appeared to be equivalent to that with only antivenom.