Some pharmacological properties of morphine-7,8-oxide (morphine epoxide).

Morphine-7,8-oxide (morphine epoxide) is assumed to be a metabolite of morphine. Morphine epoxide in antinociceptive action was practically as potent as morphine. The development of tolerance in antinociceptive action was slower in the rats treated with morphine epoxide than in the rats with morphine. Furthermore, morphine epoxide was less potent than morphine in the inhibition of abstinence syndrome.