BZD [Benzodiazepine] - Downer

MOA

GABAa enhancer - Ast as a central nervous system depressant

• Brain cells = Neurons. Sends and receive a signal through neurotransmitter like Glutamate and GABA.

• Neuron --> gets stimulated --> release nuerotransmitter such as Glutamate/GABA --> binds to other Neuron --> Depolarizes --> release another neurotransmitter from that Neuron

  • Excitatory neuron = Glutamate

  • Inhibitory neuron = GABA - GABA receptor (Ligan-gated ion channel) releases Cl- ion. when the cell becomes more Negative - Inactivates neuron

• Psychiatric disorders = Too much excitatory NT release at once [Anxtiey, Panic attack] 

• Neurological disorders = Too much inhibitory NT release at once [seizures, epilepsy] 

• BZD decreases excitatory signals --> enhancing the effect of inhibitory neuron

• BZD bind to GABAa receptor and increases intracellular Cl- level. 

  • Barbiturates also bind to GABAa receptor. It tends to open channels longer and unlike BZDs they can open this channel in absence of GABA

Indication

anxiolytic, anticonvulsant, hypnotic, anesthetic, and treat withdrawal syndromes

Drugs

Long-acting BZDs	Short-acting BZD
Diazepam (Valium)	Midazolam (Versed)
Chlordiazepoxide (Librium)	Alprazolam (Xanax)
	Lorazepam (Ativan)
	Oxazepam (Alepam)
	Temazepam (Restoril)

Use of BZD

• Anxiety disorder - panic attack

• Status Epilepticus - 5 mins of seizure, multiple seizures without returning to normal in-between 

• Anesthesia - depress the function of the nervous system

• Insomnia - depress the function of the nervous system [it decreases REM sleep]

• Withdrawal symptoms - decrease severity on alcohol withdrawal symptoms

• Muscle spasm - cerebral palsy (뇌성마비)

Side effects

• Drowsiness, decreased concentration, decreased problem-solving abilities and decreased reaction time

• Causes "Paradoxical stimulation in the brain" - fast speech, excitement, restlessness

  • in this case, we can use competitive antagonist for BZDs called Flumazenil

Contraindication

• Anything that makes the nervous system depressed such as alcohol, barbiturates, and anti-histamines

Clinical pearls

• Should not take BZDs before driving, avoid activities that require mental alertness

• With chronic use, will develop tolerance. It would decreases BZDs effect. Can lead to addiction due to habit-forming and dependence

Z-drugs are not benzodiazepine but similar. It acts on a subunit of the benzodiazepine receptor family BZ1. Zolpidem has no anticonvulsant or muscle-relaxant properties but has only a hypnotic effect. 

Z-Drugs

Zolpidem (Ambien)

Zopilcon (Imovane)

Zaleplon (Sonata)

 

References:

Pictures: https://www.theguardian.com/society/2018/feb/09/reduces-people-zombies-uk-readers-xanax-misuse

DI: http://www.osmosis.org/