When used on their own, they are considered to be a relatively safe class of drug in terms of overdose and death risk — taking them alone has rarely been implicated in overdoses. The trouble is that when benzos are mixed with alcohol or other central nervous system depressants, the effects of both substances are significantly magnified, often leading to deadly consequences.
Combining even a therapeutic dose of a drug such as Xanax with one or two servings of wine, beer or liquor can cause serious side effects such as respiratory failure, impaired cognition, and unconsciousness. This is why some benzo-related deaths involve drowning in a bathtub because the victim’s natural ability to resist drowning was completely suppressed by the drug combination in their system.
These drugs have also been implicated in the Germanwings airline tragedy in 2015, which took the lives of 150 passengers and crew aboard an Airbus A320. German prosecutors report that the co-pilot, Andreas Lubitz, was taking them to treat anxiety related to a vision problem he had, and that medication came with a warning that users may become suicidal. Investigators believe that Lubitz locked the captain out of the cockpit and deliberately flew the plane into the side of a mountain, killing himself and everyone aboard.