In a clinical study conducted in the United Kingdom between the years 1991-1993, it was found that temazepam was the most toxic of all benzodiazepines, easily causing death in an overdose, even when not combined with any other CNS Depressant, unlike most other benzodiazepines, especially the anxiolytics which all have a much lower toxicity profile. Oxazepam had the lowest toxicity profile of all benzodiazepines. Others with low toxicity profiles were diazepam, alprazolam, lorazepam, bromazepam, and clonazepam. Besides temazepam, other hypnotic benzodiazepines were tested (flunitrazepam, nitrazepam, flurazepam, midazolam, and triazolam) and all had a high toxicity profile. The reason was that the hypnotics more strongly reduced the rate of respiration, caused more sedation, were more likely to induce coma, amnesia, and hypotension. All the hypnotic benzodiazepines that were tested in the study showed that they can cause death without ingesting other CNS depressants, very much like barbiturates. Nimetazepam, though was not part of the British study is believed to have a toxicity profile similar to temazepam's.
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