Sedatives chlordiazepoxide

An example of the complex chemistry occurring upon irradiation of a seven-membered heterocycle is shown below for the case of the sedative chlordiazepoxide 22 (see Equation 99.17), where both ring contraction and expansion occur. 

In 1960, the sedative, muscle-relaxing and anticonvulsant properties of 7-chloro-tV-methyl-5-phenyl-3//-l, 4-benzodiazcpin-2-amine 4-oxide ( chlordiazepoxide ) led to its introduction into clinical use as the active ingredient of the tranquilizer Librium . 

Chlordiazepoxide (Librium, Mitran, libritabs) [C-IV] [Anxiolytic, Sedative/Hypnotic/Benzodiazepine] Uses Anx-... 

The withdrawal syndrome from ethanol includes anxiety, insomnia, possibly convulsions and visual hallucinations (delirium tremens - the Dts). It is treated or better still prevented by a calm environment, adequate (but not excessive) hydration, and careful monitoring, with the added use of anticon-vulsive/sedative agents, mainly benzodiazepines to prevent or treat convulsions. The preventive effects of benzodiazepines on withdrawal morbidity has been clearly demonstrated. There do not seem to be major differences between benzodiazepines, such as chlordiazepoxide or diazepam or others. Because of the abuse potential in these highly susceptible patients, these should be rapidly weaned, and proper prevention of relapse instituted. Other drugs such as meprobamate and clomethiazole (Hemineurin) are commonly used in some countries. The effectiveness... 

The benzodiazepines constitute the most commonly used group of anxiolytics and sedative-hypnotics. Since the first member of this group, chlordiazepoxide, was introduced, many congeners have been marketed. Most of these drugs possess anxiolytic, sedative-hypnotic, and anticonvulsant properties. Thus, the clinical indications for specific benzodiazepines are not absolute, and their uses overlaps considerably. 

Withdrawal from long-term high-dose use of alcohol or sedative-hypnotic drugs can be life threatening if physical dependence is present. Benzodiazepines, such as chlordiazepoxide Librium) and diazepam Valium), are sometimes used to lessen the intensity of the withdrawal symptoms when alcohol or sedative-hypnotic drug use is discontinued. Benzodiazepines are also employed to help relieve the anxiety and other behavioral symptoms that may occur during rehabilitation. 

B. Chlordiazepoxide, through its metabolites, has a relatively long biological half-life. It will prevent many of the severe symptoms of acute alcohol withdrawal. Buspirone is not a sedative and will not suppress alcohol withdrawal. The other agents have sedative properties and could potentially suppress alcohol withdrawal but each has a much shorter biological half-life than chlordiazepoxide. 

The CNS depressants include barbiturates, nonbarbiturate sedatives, and the benzodiazepines. As the medical use of barbiturates decreased, primarily because of their high addiction liability and the danger of acute lethality, the use of the benzodiazepine anxiolytics increased. The most commonly abused barbiturates are secobarbital, pentobarbital, and amobarbital. Pheno-barbital is not generally abused, because of its slow onset of action. The most commonly abused anxiolytics include diazepam, chlordiazepoxide, midazolam, lo-razepam, and flurazepam. These drugs are readily attainable from illicit sources. 

During the early twentieth century the barbiturates were used in children and adolescents for their sedative and hypnotic effects however, their safety profile and propensity to cause physical dependence led scientists in search of safer anxiolytics. The development of animal models of behavioral disorders facilitated the formulation of drugs with more specific central nervous system (CNS) effects. In 1959, chlordiazepoxide (Librium) was the first benzodiazepine (BZ) to receive a patent. It entered the market in 1960, followed by diazepam (Valium) in 1963. Today, over 35 BZs have been formulated and over 10 are available in the United States (Ballenger, 1995 Hobbs et ah, 1996). 

Long-acting drugs such as chlordiazepoxide and diazepam and, to a lesser extent, phenobarbital are administered in progressively decreasing doses to patients during withdrawal from physiologic dependence on ethanol or other sedative-hypnotics. Parenteral lorazepam is used to suppress the symptoms of delirium tremens. 

Similarly, the category of N-oxides comprises compounds of considerable pharmacological interest. Chlordiazepoxide (18) possesses potent antidepressant, sedative, anticonvulsant and muscle relaxant properties80. Minoxidil (19) is an antihypertensive of the vasodilatator type. Ciclopirox (20) shows antifungal activity81. 

OFFICIAL NAMES Minor tranquilizers (sedative-hyp-notics/anxiolytics)/Benzodiazepines Alprazolam (Xanax) chlordiazepoxide (Librium, Novopoxide) clonazepam (Klonopin) clorazepate (Azene, Tranxene) diazepam (Valium) estazolam (ProSom) flunitrazepam (Rohypnol/illegal in the United States) flurazepam (Dalmane) halazepam (Paxipam) lorazepam (Ativan) midazolam (Versed) oxazepam (Serax) prazepam (Centrax) quazepam (Doral) temazepam (Restoril) triazolam (Halcion)... 

The rates of oral absorption of benzodiazepines differ depending on a number of factors, including lipophilicity. Oral absorption of triazolam is extremely rapid, and that of diazepam and the active metabolite of clorazepate is more rapid than other commonly used benzodiazepines. Clorazepate is converted to its active form, desmethyldiazepam (nordiazepam), by acid hydrolysis in the stomach. Oxazepam, lorazepam, and temazepam are absorbed from the gut at slower rates than other benzodiazepines. The bioavailability of several benzodiazepines, including chlordiazepoxide and diazepam, may be unreliable after intramuscular injection. Most of the barbiturates and other older sedative-hypnotics are absorbed rapidly into the blood following their oral administration. 

Lipid solubility plays a major role in determining the rate at which a particular sedative-hypnotic enters the central nervous system. For example, diazepam and triazolam are more lipid-soluble than chlordiazepoxide and lorazepam thus, the central nervous system actions of the former drugs are... 

The short-term effects are mainly those of sedation but following longer-term use accumulation may occur, particularly in the case of drugs like diazepam and chlordiazepoxide that have long half-lives due to their active metabolites. After long-term administration (weeks to months) tolerance develops. While most patients rapidly become tolerant to the sedative side effects of these drugs, some patients, particularly the elderly, experience excessive sedation, poor memory and concentration, motor incoordination and muscle weakness. In extreme cases in the elderly, an acute confusional... 

Historically the first sedative hypnotics to be introduced were the bromides in the mid 19th century, shortly followed by chloral hydrate, paraldehyde and urethane. It was not until the early years of this century that the first barbiturate, sodium barbitone, was developed and this was shortly followed by over 50 analogues, all with essentially similar pharmacological properties. The major breakthrough in the development of selective, relatively non-toxic sedative hypnotics followed the introduction of chlordiazepoxide in 1961. Most of the benzodiazepines in current use have been selected for their high anxiolytic potency relative to their central depressant effects. Because of their considerable safety, the benzodiazepines have now largely replaced the barbiturates and the alcohols, such as chloral hydrate and trichloroethanol, as the drugs of choice in the treatment of insomnia. 

The introduction of chlordiazepoxide (Librium) into clinical medicine in 1961 ushered in the era of benzodiazepines. Most of the benzodiazepines that have reached the marketplace were selected for their effectiveness as antianxiety agents, not for their ability to depress CNS function. However, all benzodiazepines possess sedative-hypnotic properties to varying degrees these properties are extensively exploited clinically, especially to facilitate sleep and ease anxiety. Mainly because of their remarkably low capacity to lead to fatal suppression of key CNS functions, the benzodiazepines have displaced barbiturates as sedative-hypnotic agents. 

The antianxiety effects of chlordiazepoxide (165) were described in 1960 and this compound was followed by diazepam (135). These two drugs have captured 75% of the market for sedatives in the USA. Other benzodiazepines used as antianxiety agents include oxazepam (166 R = H), a metabolite of diazepam that is better tolerated, lorazepam (166 R = Cl) and potassium clorazepate (167). Prazepam is the iV-cyclopropylmethyl analogue of diazepam. The benzodiazepines have other therapeutic applications, many being used for inducing sleep, diazepam and nitrazepam are anticonvulsants and flurazepam (168) is both an antianxiety agent and a potent hypnotic. Thieno- and pyrazolo-1,4-diazepinones isosteric with diazepam have similar pharmacological properties (B-81 Ml 10604). 

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