On the one hand, the use of several drugs of unidirectional action carries risks of increasing their direct effects and side effects, but on the other hand, when several drugs are prescribed together, their doses are correspondingly reduced, which can also be useful, since when the dose is reduced, the risk of side effects decreases (if they don't match).
Combining barbiturates and anxiolytics is not the best option. Barbiturates are quite an old group of drugs and have many unpleasant side effects (there are a lot of substitutes for them), although the same cannot be said about afobazole (it is just weak).
Opening Barboval's instructions ..
Interaction with other drugs
Simultaneous use with neuroleptics and tranquilizers potentiates, and central nervous system stimulants - weakens the effect of each component of the drug ...
Now open the Afobazole instructions
Pharmacotherapeutic group: anxiolytic agent (tranquilizer).
Since Afobazole is an anxiolytic agent, therefore the drugs will potentiate.
Potentiation (in pharmacology) is a type of drug interaction, which is a special case of synergism. In the case of potentiation, the effect of the simultaneous use of several drugs is significantly greater than the sum of the effects of each drug applied separately in the same dose.
It is not difficult to assume that, as in the case of an overdose, there is a health hazard.
I will write here at the beginning a lot-many-many-many-a lot of any secondary and unnecessary text, in order to answer just like this: why?