Benzodiazepines Addiction, Dependency and Tolerance (General Touch)

Class

They belong to the class of drugs anxiolytics (Sedatives) and hypnotics. Cause sedation with the concomitant relief from anxiety.

Type of Effects

 Include sedation when taken in low to moderate dose. At high dose they cause hypnosis and further at very high dose impair the brain function by severely depressing its electrical activity.  

Benzodiazepines are the most widely used anxiolytics, by replacing barbiturates and meprobamate.

Effects on the body: -

1)    Sedation:- They cause calming effect with concomitant anxiolytic effect. This response is due the effect on the central nervous system, By decreasing the electrical activity. Sedative and anxiolytic effect is some time accompanied with depressive effect on psychomotor and cognitive functions.

2)    Hypnosis :- hypnosis is also centrally mediate function of benzodiazepines, which occur on high doses. They cause hypnosis by decreasing latency of sleep (time to fall a sleep), increase Non-Rapid eye moment sleep, and decrease Rapid Eye movement sleep.

3)    Anesthesia:- As shown previously at higher doses then required for hypnosis they depress central nervous system to a point of stage 3 general anesthesia.

4)    Anticonvulsant effect:- Many benzodiazepines have ability to prevent the generation of epileptiform electrical activity in the CNS.  Selective agent having this tendency include lorazepam, diazepam, clonazepam and Nitrazepam.

5)    Muscles Relaxation:- at high doses they my inhibit transmission at muscular level by locally affecting neurons there. And also mediated by presynaptic inhibition of spinal cord.

6)    Effect on Respiration and CVS:- This respiratory depression is due to the medullary  respiratory center suppression. Even at normal dose it may impair respiratory functions in susceptible and respiratory patient.  In contrast to Respiratory functions CVS function are no announced in normal people even at hypnotic dose. But may affect people with hypovolemic status, CVS diseases and Heart failure. This action is due to suppression of medullary vasomotor area of the hind brain.

7)    Anterograde amnesia:- Short term memory loss is due to the effect on CNS by alpha1 GABA sub type. In this duration of maintained dose individual become un-aware of environment.

Addiction

If used in a high doses for prolong time they can cause dependency ( fall in Schedule 4 of controlled substances having a low potency to cause dependency and Addiction). This dependency is due to the effect on reward pathway. Where it the drugs cause increase in the level of neurotransmitters particularly dopamine (causing euphoria, state of relaxation and calmness). This stimulation of reward pathway lead to Psychological dependency. Dependency is also due to prevent the with drawl effects associated with benzodiazepines like insomnia, anxiety and central nervous system excitability that may lead to convulsion.

Tolerance to Benzodiazepines

Tolerance to benzodiazepines is not likely to be contributed by metabolic induction. Here increase metabolism play little to no role in tolerance. Benzodiazepines tolerance is due to down regulation of receptors. Tolerance to benzodiazepines is not vary abrupt and take long time to be generated.

With drawl of benzodiazepines include symptoms like

Anxiety, depression, increased heart rate, insomnia, high blood pressure, excessive sweeting, tremors, hallucination, seizures and convulsions.