Benzodiazepines muscle relaxation

F. (1989). Electrophysiological studies with a 2,3 benzodiazepine muscle relaxant GYKI 52466. Eur. J. Pharmacol. 167 193-199. 

Anxiolytics are drugs used for the treatment of anxiety disorders. Apart from benzodiazpines, a frequently used anxiolytic is the 5HT1A (serotonin) receptor agonist buspiron, which has no sedative, amnestic or muscle-relaxant side effects, but whose action takes about a week to develop. Furthermore, it is less efficaceous than the benzodiazepines. Buspiron s mechanism of action is not fully understood. 

Benzodiazepines have found wide therapeutic applications as anxiolytics, sedatives, hypnotics, anticonvulsants, and central muscle relaxants. 

Benzodiazepines are amongst the most frequently prescribed drugs they have well-established uses in the treatment of anxiety disorders (anxiolytics) and insomnia, preanaesthetic sedation, suppression of seizures, and muscle relaxation. 

The estimated sensitivity of skin tests for muscle relaxants is approximately 94-97%. Sensitivity for other substances varies. It is good for synthetic gelatins, (3-lactams, but poor for barbiturates, opioids and benzodiazepines dyes, and chlorhexidine. 

Benzodiazepine The family name for a group of drugs with anticonvulsant, muscle relaxant and sedative-hypnotic properties. Examples include chlorodiazepoxide (Librium), diazepam (Valium), flunitrazepam and temazepam. These drugs have largely superseded the barbiturates. 

Zolpidem, chemically unrelated to benzodiazepines or barbiturates, acts selectively at the y-aminobutyric acidA (GABAA)-receptor and has minimal anxiolytic and no muscle relaxant or anticonvulsant effects. It is comparable in effectiveness to benzodiazepine hypnotics, and it has little effect on sleep stages. Its duration is approximately 6 to 8 hours, and it is metabolized to inactive metabolites. Common side effects are drowsiness, amnesia, dizziness, headache, and GI complaints. Rebound effects when discontinued and tolerance with prolonged use are minimal, but theoretical concerns about abuse exist. It appears to have minimal effects on next-day psychomotor performance. The usual dose is 10 mg (5 mg in the elderly or those with liver impairment), which can be increased up to 20 mg nightly. Cases of psychotic reactions and sleep-eating have been reported. 

The clinical consequences of the currently used benzodiazepines range from sedation, muscle relaxation, seizure reduction, anxiolysis, and hypnosis. Clearly, it would be highly desirable to be able to separate some of these effects. In addition, it would be useful to reduce other undesirable consequences such as development of tolerance and dependence, abuse, synergistic interaction with ethanol, and memory impairment (for a comprehensive review see [22]). Animal models for some of the aforementioned conditions, in combination with transgenic mouse technology, have recently led to a deeper understanding of the contribution some of the individual a subunits make to these behaviors. 

Drugs that increase sedation and give muscle relaxation can have a negative effect on muscle strength and the ability to maintain physical activity, for example, benzodiazepines and other tranquilizers. Corticosteroids have a well known side effect on muscle tissue that leads to muscle atrophy and increases with the dosage. 

Sedative and anxioiytic effects A number of flavonoids have been shown to bind to benzodiazepine receptors and have anxiolytic effects (Medina et al. 1997). The anxiolytic effects of chrysin were examined in mice (Wolfman et al. 1994). Chrysin (1 mg/kg IP) reduces behavioral measures of anxiety (elevated-plus maze) in a manner similar to diazepam (0.3-0.6 mg/kg), which was reversed by pretreatment with a benzodiazepine antagonist, Ro 15-1788. The anxiolytic effect is not likely due to sedation because there is no concurrent reduction in motor activity at the doses used. Unlike diazepam, chrysin does not produce muscle relaxation at higher doses. 

Benzodiazepines have a wide array of clinical uses. In addition to relieving anxiety, they can be used to treat epilepsy, alcohol withdrawal, insomnia, agitation, and perhaps impulsivity. They can also be used as muscle relaxants or to produce conscious sedation during certain medical procedures such as cardiac catheterization and colonoscopy. 

Buspirone (Buspar). The first nonsedating, nonbenzodiazepine specifically introduced as an anxiolytic, buspirone is FDA approved for the treatment of GAD. This medication acts as a partial agonist at the postsynaptic serotonin (5HT)-1A receptor. Like the antidepressants, buspirone has a delayed onset of action and effectively relieves the intrapsychic symptoms of GAD. Devoid of the muscle-relaxing properties of benzodiazepines, buspirone does not as effectively relieve the physical symptoms of GAD. Buspirone is not effective in the treatment of depression. Furthermore, its utility for the treatment of anxiety disorders other than GAD appears to be limited. 

Benzodiazepines. Safer than the barbiturates but acting in a similar manner, the benzodiazepines have largely replaced barbiturates since their introduction in the 1960s. Other uses of benzodiazepines include treatment for epilepsy, alcohol withdrawal, several anxiety disorders, agitation, and impulsivity, as muscle relaxants, and as conscious sedation during certain medical procedures. 

While the individual drugs in the benzodiazepine group differ in potency, all benzodiazepines in common use have anxiolytic, sedative-hypnotic, anticonvulsant and muscle-relaxant activity in ascending order of dose. The main clinical difference between the individual drugs lies in the time of onset of their therapeutic effect, and the intensity and duration of their clinical activity. 

The anxiolytic properties of 5-HT3 receptor antagonists have been demonstrated in several animal models of anxiety. In these models, the 5-HT3 antagonists mimic the anxiolytic effects of the benzodiazepines but differ from the latter in their lack of sedative, muscle relaxant and anticonvulsant action. These compounds appear to be extremely potent... 

Benzodiazepines modify affective responses to sensory perceptions specifically, they render a subject indifferent towards anxiogenic stimuli, i.e., anxiolytic action. Furthermore, benzodiazepines exert sedating, anticonvulsant, and muscle-relaxant (myotonolytic, p. 

The development of the benzodiazepine class of drugs for the treatment of a variety of neurological indications has proven to be an outstanting success story in the field of chemotherapy. However, these compounds often produce undesirable side effects when used as anti-anxiety or hypnotic agents. These side effects include sedation, physical dependence, amnesia, muscle relaxation, and ethanol potentiation. The development of a benzodiazepine receptor-based anxiolytic agent devoid of these side effects would constitute a major advance in the field and has been the focus of significant research efforts [284]. 

The synthesis of these compounds will be described in Section 3.1, Opioid analgesics. Besides opioids, benzodiazepines (diazepam, lorazepam, and midazolam), which have anxiolytic, sedative, and anticonvulsant effects, that cause amnesia and muscle relaxation, are frequently used to relieve patients anxiety during anesthesia. 

Buspirone is an extremely specific drug that could possibly represent a new chemical class of anxiolytics—azaspirones. As an anxiolytic, its activity is equal to that of benzodiazepines however, it is devoid of anticonvulsant and muscle relaxant properties, which are characteristic of benzodiazepines. It does not cause dependence or addiction. The mechanism of its action is not conclusively known. It does not act on the GABA receptors, which occurs in benzodiazepine use however, it has a high affinity for seratonin (5-HT) receptors and a moderate affinity for dopamine (D2) receptors. Buspirone is effective as an anxiolytic. A few side effects of buspirone include dizziness, drowsiness, headaches, nervousness, fatigue, and weakness. This drug is intended for treatment of conditions of anxiety in which stress, muscle pain, rapid heart rate, dizziness, fear, etc. are observed in other words, conditions of anxiety not associated with somewhat common, usual, and everyday stress. Synonyms for buspirone are anizal, axoren, buspar, buspimen, buspinol, narol, travin, and others. 

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