Lorazepam

A benzodiazepine refers to any chemical that includes a benzene ring fused to a diazepine ring [128].

Most of the drugs in this class work by slowing down brain activity. This gives them hypnotic, anxiolytic, muscle-relaxant, and in some cases, intoxicating qualities. The most common benzos today are Xanax, Valium, Librium, and Klonopin. There is also a large selection of designer benzodiazepines (called DBZDs for short) — which refer to benzodiazepine compounds that have not been formally tested.

Most benzodiazepine drugs work by enhancing the effects of the neurotransmitter GABA on the GABA-A receptors.

GABA is the primary neuro-inhibitory molecule in the brain — meaning it works to reduce brain activity. When brain activity is reduced, we feel less anxiety and more sedated. Benzos act as a “chill pill” — removing the constant sense of worry and allowing users to temporarily stop caring about their problems.

This fades when the drug’s effect wears off.

Unfortunately, inhibiting brain activity affects other areas of cognition as well:

1. Benzos inhibit memory formation — causing frequent lapses in memory or “blackouts.”
2. Benzos block one’s ability to form complex or abstract thoughts.
3. Benzos induce a state of disinhibition similar to alcohol — causing people may say or do things they normally wouldn’t.

Some of the more potent benzodiazepines are used in surgery — such as midazolam and remimazolam. These drugs inhibit the ability to form memories and act as sedatives.

The most common method of grouping benzodiazepines is by their duration of effects (short, intermediate, or long-acting). This is because the duration of effects is the best factor for determining what the drug should be used for and what level of risk for addiction or overdose it carries.

The “action” of a benzodiazepine is determined by its half-life (how long it takes for half the drug to be eliminated from the body).

Benzos can be classified into three main groups depending on the duration of effects. 

Short-acting benzodiazepines enter and leave the body quickly.

Anything with a half-life between 1 and 12 hours is classified under this group. This means the drug remains in the system for around 24 hours or less.

Short-acting benzos are usually preferred for treating insomnia because they tend to kick in quickly to help the patient get to sleep but wear off long before the patient wakes up. Most benzodiazepines interfere with REM sleep, so the sooner it wears off while asleep, the better.

These drugs have the lowest risk for accumulation and overdose with repeated use but are at high risk for abuse and addiction because users need to redose more often. Many of the drugs in this class have been replaced with a newer class of hypnotic drugs called Z-drugs, which have less of an impact on deep sleep [44].

Intermediate-acting benzodiazepines have a median half-life between 12 and 40 hours. This means these drugs can remain in the system anywhere from 1 to 3 days.

This group is also popular for managing anxiety and insomnia and are often prescribed instead of short-acting benzos as a way to lower the risk of the patient forming dependence on the drug.

Long-acting benzodiazepines are often used for things like anesthesia during surgery, managing alcohol withdrawal syndrome, or long-term anxiety support.

These drugs take a long time to leave the body and tend to leave patients with a hangover effect when taking them to manage anxiety or insomnia.

In order to classify as a long-acting benzodiazepine, the drug must have a half-life between 40 and 125 hours. These drugs can remain in the system for several days.