Naloxone benzoylhydrazone

Analgesic studies in mice examining increasing doses of Naloxone benzoylhydrazone with a fixed dose of morphine reveals a biphasic curve. Naloxone benzoylhydrazone at doses as low as 1 μg/kg partially antagonized morphine analgesia. Higher Naloxone benzoylhydrazone doses continued to inhibit morphine analgesia in a dose-dependent manner, with the 1-mg/kg dose antagonizing completely morphine analgesia. As the Naloxone benzoylhydrazone dose increased beyond 1 mg/kg analgesia returned. Naloxone benzoylhydrazone also prduces a similar analgesic response when administered alone in mice and also is active in rats. Naloxone benzoylhydrazone has excellent p.o. activity, with an analgesic potency in mice equivalent to s.c. administration. In addition to blocking morphine analgesia, low doses of Naloxone benzoylhydrazone also partially reverses the inhibition of gastrointestinal transit in mice produced by morphine, antagonizes completely morphine lethality and precipitates withdrawal in morphine-dependent mice^[4].