Comparative study of the inductive effect of two psychomoderators--tetrabamate and complexe 1656--and of phenobarbital on liver microsomal enzymes in rats.

Tetrabamate (Atrium) and Complexe 1656, two psychosedative drugs, are complexes formed by phenobarbital with its N-substituted derivatives. We have studied the induction effect of all these compounds on the microsomal liver enzymes in male rats. Tetrabamate and Complexe 1656 were found to be equally effective in increasing the amount of microsomal proteins, cytochrome P-450 and the in vitro aniline p-hydroxylation and amino-pyrine N-demethylation activity. These effects were similar to those obtained after a treatment with an equivalent dose of phenobarbital. Febarbamate and difebarbamate had no significanteffect on microsomal enzymes. The inductive effect of tetrabamate and of its analogue seems essentially due to the phenobarbital content of these complexes.