The pharmacology of thebaine in the chronic spinal dog.

The effects of thebaine were studied in nondependent and morphine-dependent chronic spinal dogs as well as in chronic spinal dogs receiving thebaine chronically. Thebaine did not produce any morphine-like effects in nondependent dogs nor did it precipitate an abstinence syndrome in morphine-dependent dogs. Large doses of naltrexone precipitated a mild abstinence syndrome in dogs receiving thebaine chronically; however, no withdrawal abstinence syndrome was observed after abrupt withdrawal. Thebaine is not a morphine-like drug, nor does it produce appreciable physical dependence in the dog.