[Cross tolerance when benzodiazepines are administered with other substances].

It has been demonstrated in experiments on rats that only the drugs of benzodiazepine structure are responsible for complete cross tolerance as regards the myorelaxant effect under application with phenazepam. Other substances such as neuroleptics (chlorpromazine, triftazin), ethanol, phenobarbital, tranquilizers of non-benzodiazepine structure (meprobamate, ataractic), and an agonist of GABA receptors, muscimol, in doses that produce myorelaxation are not capable to replace phenazepam under conditions of this drug tolerance development. Partial cross tolerance under application with phenazepam arises from the use of supposed endogenous ligands of benzodiazepine receptors, nicotinamide and inosine, as well as of the use of the GABA-mimetic calcium valproate. The mechanisms of benzodiazepine tolerance development are discussed.