Benzodiazepine
In pharmacology, benzodiazepines (BZD) are a class of medications that are "a group of two-ring heterocyclic compounds consisting of a benzene ring fused to a diazepine ring."[1] All benzodiazepines affect specific benzodiazepine receptors and modulate gamma-aminobutyric acid. Specific benzodiazepines also affect other neurotransmitters (e.g., clonazepam and alprazolam affect serotonin). Receptor relationships are quite complex and are discussed further below.
Uses include the treatment of anxiety disorders and alcohol withdrawal syndrome. Some are used as anticonvulsants and to treat musculoskeletal spasticity.
| Half life | Examples |
|---|---|
| ultra-short | |
| short (< 6 hrs) | midazolam triazolam |
| intermediate (6 - 24 hrs) | alprazolam estazolam lorazepam oxazepam temazepam |
| long (> 24 hrs) | chlordiazepoxide flurazepam diazepam quazepam. |
Receptors
Part of the confusion in the receptors they affect come from the observation that what had previously been considered the GABAA-benzodiazepine-Cl- channel complex receptor has numerous sub-receptors, in five classes (α, β, γ, δ, ρ) with at least 16 subtypes. Benzodiazepine receptor type 1, for example, involves binding to α1, β2 and γ2.[3] The interactions among GABA, benzodiazepines, and some other classes of drugs are even more complex, in that binding to one receptor type affects other receptors. For example, certain bindings to benzodiazepine receptors will increase the rate of opening of the GABAA receptor,[4] potentiating the effect of both endogenous GABA and GABA released by direct GABA agonists such as baclofen.
There can be synergism in the use of various drugs that affect GABA. In musculoskeletal spasticity, as in multiple sclerosis or various disorders of spinal nerves, the first antispasticity drug prescribed is usually the GABA agonist baclofen, but it may be supplemented the BZD diazempam; diazepam can also be used as an alternative. In one study, the GABA agonists baclofen and muscimol were potentiated pain relief in rats when combined with the benzodiazepine diazepam. [5]
Clinical use
Anxiety
Convulsive disorders
Musculoskeletal spasticity
Toxicity and abuse
References
- ↑ Anonymous (2024), Benzodiazepine (English). Medical Subject Headings. U.S. National Library of Medicine.
- ↑ Charney Dennis S, Mihic S. J, Harris R. A, "Chapter 16. Hypnotics and Sedatives" (Chapter). Brunton LL, Lazo JS, Parker KL: Goodman & Gilman's The Pharmacological Basis of Therapeutics, 11e:.
- ↑ Ross J. Baldessarini (1996), Chapter 18, Drugs and the treatment of Psychiatric Disorders: Psychosis and Anxiety, in Joel G. Hardman et al., Goodman and Gilman's The Pharmacological Basis of Therapeutics (Ninth Edition ed.), McGraw-Hill, ISBN 0070262667 pp. 421-434
- ↑ Robin Mantooth (28 January 2010), Toxicity, Benzodiazepine, eMedicine
- ↑ Kaoru Hara et al. (May 2004), "The Interaction Between Gamma-Aminobutyric Acid Agonists and Diltiazem in Visceral Antinociception in Rats", Anesthesia and Analgesia 98 (5): 1380-1384, DOI:01.ANE.0000107935.84035.48 10.1213/ 01.ANE.0000107935.84035.48