EFFICACY OF HI-6 AND HLO-7 IN PREVENTING INCAPACITATION FOLLOWING NERVE AGENT POISONING

The therapeutic efficacy of the oximes HI-6 and HLo-7 (132.5 pmol/kg), in combination with atropine, in soman- or tabun-intoxicated guinea p igs was compared, particularly with respect to recovery of shuttlebox performance and electroencephalograms (EEGs). After 1.5 x LD(50) soman SC, therapy with HI-6 or HLo-7 resulted in survival of 87.5% of the a nimals in each group. In both groups postintoxication performance decr ements and EEG abnormalities lasted approximately 2 weeks after intoxi cation. After 3 x LD(50) soman all HLo-7-treated animals died within 5 h; 70% of the HI-6-treated animals were still alive after 8 h; howeve r, only 10% survived more than 24 h. After 2 x LD(50) tabun 36% of the HI-6-treated animals died; HLo-7 prevented lethality and led to faste r recovery of performance and EEG than after HI-6. Even after 7.5 x LD (50) tabun, followed by HLo-7, full recovery was reached within 1 week in the surviving animals (82%). In soman-intoxicated guinea pigs HI-6 is therapeutically slightly more effective than HLo-7. HLo-7 is far m ore effective, under similar conditions, against tabun intoxication th an HI-6.