That benzodiazepines, barbiturates and ethanol all have related actions on a common receptor type, which explains their pharmacologic synergy and cross tolerance.
Thus, benzodiazepines are used during alcohol detoxification.
These specific amnestic effects appear to be separate from sedation.11 Episodic memory (the remembering of recent events and the circumstances in which they occurred and their time sequences) is particularly impaired and more markedly so in heavy alcohol drinkers who also use benzodiazepines.
Specific deficits in visuospatial ability and sustained attention have also been described in patients who have taken therapeutic doses of benzodiazepines regularly for longer than one year.13Increased excitement, irritability, aggression, hostility and impulsivity may occur in some patients who take benzodiazepines.
In addition, pharmacokinetic drug interactions may occur.
For instance, selective serotonin reuptake inhibitors (SSRIs) may increase diazepam blood levels,9 and nefazadone (Serzone) may increase alprazolam levels10 through hepatic enzyme inhibition, leading to increased sedative-hypnotic effects or side effects.
This effect may be sought by drug addicts who become progressively more incapable of tolerating their emotions and life stressors.
When used alone, benzodiazepines carry an extremely low risk of acute toxicity.
An association has been noted between benzodiazepine use and depressive symptoms and, in some cases, the emergence of suicidal ideation.
Some evidence indicates that higher benzodiazepine dosages are associated with an increased risk of depression and that reducing the dosage or discontinuing therapy may resolve the depressive symptoms.15 Although the mechanism of this action is unclear, benzodiazepine-related depression might occur as a physiologic result of a reduction in central monoamine activity.“Emotional anesthesia” may also be seen in clinical practice.
Psychomotor slowing may be especially profound following initial administration of a benzodiazepine or with a sudden dosage increase.
It also may be noted in patients, such as the elderly, who have decreased rates of metabolism or greater susceptibility to central nervous system depression.8 Psychomotor symptoms include drowsiness, poor concentration, ataxia, dysarthria, motor incoordination, diplopia, muscle weakness, vertigo and mental confusion.11 Studies of the psychomotor effects suggest that benzodiazepines slow reaction time and impair driving skills, increasing the risk of motor vehicle crashes in patients who are taking these agents.12Benzodiazepines induce anterograde amnesia, which accounts for the beneficial effects of benzodiazepines such as midazolam (Versed) for presurgical medication.