Benzodiazepines are a class of drugs primarily used for treating anxiety, but they also are effective in treating several other conditions. The exact mechanism of action of benzodiazepines is not known, but they appear to work by affecting neurotransmitters in the brain, chemicals that nerves release in order to communicate with other nearby nerves. One of these neurotransmitters is gamma-aminobutyric acid (GABA), a neurotransmitter that suppresses the activity of nerves. Scientists believe that excessive activity of nerves may be the cause of anxiety and other psychological disorders, and benzodiazepines reduce the activity of nerves in the brain and spinal cord by enhancing the effects of GABA.

• Diazepam (Valium) and clorazepate (Tranxene) have fast onsets of action and usually start working within 30 to 60 minutes.
• Oxazepam (Serax) has a slow onset, and lorazepam (Ativan), buy alprazolam (Xanax), and clonazolam ) have intermediate onsets of action.
• Clorazepate (Tranxene), midazolam (Versed), and triazolam (Halcion) are short-acting agents with durations of action of 3 to 8 hours.
• Alprazolam (Xanax), lorazepam (Ativan) etizolam (Prosom), and temazepam (Restoril) are intermediate-acting agents with durations of action of 11 to 20 hours.
• Chlordiazepoxide (Librium), clonazepam (Klonopin), diazepam (Valium), flurazepam (Dalmane), and quazepam are long-acting agents with duration of action of 1 to 3 days.