It was later found that scopolamine impairment in learning was caused by an increase in benzodiazepine/GABA activity (and that benzodiazepines were not associated with the cholinergic system). In tests of various benzodiazepine compounds, chlordiazepoxide was found to cause the most profound reduction in the turnover of 5HT (serotonin) in rats. Serotonin is closely involved in regulating mood and may be one of the causes of feelings of depression in rats using chlordiazepoxide or other benzodiazepines. In September 2020, the U.S. Food and Drug Administration (FDA) required the boxed warning be updated for all benzodiazepine medicines to describe the risks of abuse, misuse, addiction, physical dependence, and withdrawal reactions consistently across all the medicines in the class. Tolerance and dependence
Tolerance
Chronic use of benzodiazepines, such as chlordiazepoxide, leads to the development of tolerance, with a decrease in number of benzodiazepine binding sites in mouse forebrain. The Committee of Review of Medicines, who carried out an extensive review of benzodiazepines including chlordiazepoxide, found—and were in agreement with the Institute of Medicine (USA) and the conclusions of a study carried out by the White House Office of Drug Policy and the National Institute on Drug Abuse (USA)—that there was little evidence that long-term use of benzodiazepines were beneficial in the treatment of insomnia due to the development of tolerance.
Participants daily dosage ranged from 5 to 100 milligrams.Chlordiazepoxide is a drug of potential misuse and is frequently detected in urine samples of drug users who have not been prescribed the drug. Legal status
Internationally, chlordiazepoxide is a Schedule IV controlled drug under the Convention on Psychotropic Substances. Toxicity
Animal
Laboratory tests assessing the toxicity of chlordiazepoxide, nitrazepam and diazepam on mice spermatozoa found that chlordiazepoxide produced toxicities in sperm including abnormalities involving both the shape and size of the sperm head. Nitrazepam, however, caused more profound abnormalities than chlordiazepoxide. Availability
Chlordiazepoxide is available in various dosage forms, alone or in combination with other drugs, worldwide. In combination with Clidinium as NORMAXIN-CC and in combination with dicyclomine as NORMAXIN for IBS, and with the anti-depressant Amitriptyline as Limbitrol. See also
Alcohol withdrawal syndrome
Effects of long-term benzodiazepine use
Benzodiazepine withdrawal syndrome
Benzodiazepine dependence
Benzodiazepine

References
External links
Rx-List.com - Chlordiazepoxide
Inchem.org - Chlordiazepoxide
U.S. National Library of Medicine: Drug Information Portal - Chlordiazepoxide