Z-Drugs in the Environment: A Review

According to the World Health Organization (WHO), substance dependence and mental health disorders, such as anxiety, depression, post-traumatic stress disorder (PTSD), insomnia, bipolar disorder, and schizophrenia, affect >360 million people worldwide. As a result the increasing use of psychoactive pharmaceuticals, including non-benzodiazepines (also referred to as Z-drugs), has been observed. The COVID-19 pandemic has also had an additional significant negative effect on people’s mental health. Among the aforementioned mental health disorders, chronic insomnia is reported to affect approximately 10% of the adult population. Z-drugs are frequently used in the treatment of insomnia due to their rapid onset of action. They are metabolized in the human organism, but noticeable amounts of the original compound are released to the environment via household wastewater. The extensive use of these pharmaceuticals has led to growing concern about the occurrence of their residues in the environment. Unfortunately, the information on the analytical methods for determining Z-drugs, their main metabolites and transformation products in the environment, efficiency of their removal in wastewater treatment plants, their fate, their presence in environmental matrices, and their ecotoxicological effects is limited. This review paper focuses on summarizing data on these topics. To the best of our knowledge, such a comprehensive review has not yet been published.