Death may occur when barbiturates are combined with depressants such as opiates, benzodiazepines, gabapentinoids, thienodiazepines, alcohol or other GABAergic substances.[1] It is strongly discouraged to consume moderate to heavy dosages of these substances together.
Source: PsychonautWiki — Barbiturates ↗
Fact-sheets from PsychonautWiki. Harm-reduction reference only — not medical advice.