Benzodiazepines and another downer: alcohol or GHB
Both alcohol and benzodiazepines have a depressant effect in the body. They inhibit activity in your brain. The combination could put you in a coma (pass out), suffer a respiratory arrest or choke on your own vomit. Your body can then no longer respond properly if you vomit and if you lie on your back, for example, you can choke on your own vomit. This combination can also lead to unpredictable and reckless behavior. After using benzodiazepines, you often don’t remember what you did.
Keep in mind that some benzodiazepines stay in your body for a very long time. They have a long half-life. So even the day after you take a benzodiazepine, it can still affect another drug that you are taking.