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By Kevin Shanks, D-ABFT-FT

What are Designer Benzodiazepines? 

Designer benzodiazepines are substances synthesized to mimic the effects of traditional benzodiazepines, which are commonly prescribed for anxiety, insomnia, and other conditions. Unlike their pharmaceutical counterparts, designer benzodiazepines are often created in clandestine laboratories with the intention of circumventing the controlled substances act and other legal restrictions. These benzodiazepine compounds have similar sedative and anxiolytic effects but may also come with unpredictable purity, potency, and adverse effects mainly due to their unregulated production. Their emergence and proliferation on the illicit market present significant challenges for public health officials, coroners and medical examiners, and law enforcement, as they can lead to substance abuse, pose serious health risks to users, and potentially cause death in overdose. 

Benzodiazepines work by affecting the central nervous system, primarily through action via gamma-aminobutyric acid (GABA). GABA is an inhibitory neurotransmitter that helps reduce excitability of neurons and essentially calms the brain’s activity. When the substance binds to the GABA receptor, chloride channels in the receptor open – this allows chloride ions to enter the nerve cell. This influx of chloride ions makes the neuron more negatively charged, which makes it less likely to relay a signal and slows down brain activity, which results in sedative, muscle relaxant, and anxiety reducing effects. While effective for their intended pharmaceutical uses as medications, benzodiazepines can also lead to tolerance, dependence, and withdrawal symptoms if used for prolonged periods or at high doses. Common adverse effects of the use of these compounds include drowsiness, tiredness, sedation, loss of motor coordination, slurred speech, amnesia, and respiratory depression. 

Some examples of designer benzodiazepines are: 

• Bromazolam – Bromazolam is a drug that has a history in pharmaceutical drug development as it was first synthesized in the 1970s as XLI-268, but it was never approved for medicinal use. The first emergence of bromazolam on the illicit drug market in the United States was in 2019, but it did not become prevalent until more recently. The substance is the brominated analog of alprazolam, meaning it has a bromine atom in the place of the typical chlorine atom. It is not currently considered a controlled substance by the United States Federal government. 
• Clonazolam – Clonazolam is a drug that was first reported in 1971 in scientific research, but it did not become a pharmaceutical medication. Reports include strong sedative effects. It has recently been sold online as a novel psychoactive substance and in 2023, it was made a Schedule I controlled substance in the United States by the Federal government. 
• Etizolam – Etizolam is a substance that was first patented in 1972, but is currently used as a pharmaceutical medication for the treatment of anxiety and insomnia in Italy and India. It is not authorized for use as a medicine in the United States and was first detected in the States in 2015-2016. It became a Schedule I controlled substance at the Federal level in 2023. 
• Flubromazepam – Flubromazepam is a drug that also has a history in pharmaceutical drug development. It was first synthesized in 1960, but it did not receive any further study as a medicine. It appeared on the illicit drug market in 2012, but didn’t gain any traction for several years. Flubromazepam is a fluorinated analog of phenazepam, a benzodiazepine used as a medicine in Russia, meaning it has a fluorine atom in the place of the typical chlorine atom. It is not currently considered a controlled substance by the United States Federal government. 
• Gidazepam (Desalkylgidazepam) – Gidazepam is a benzodiazepine used in Russia as a pharmaceutical medication for anxiety and certain cardiovascular disorders such as cardiac arrhythmias. Gidazepam acts as a prodrug and is rapidly metabolized to an active metabolite, desalkylgidazepam, which has a very long half-life (87 hours).  Gidazepam is not currently considered a controlled substance by the United States Federal government.

Chemical Structure of the Designer Benzodiazepine Bromazolam Drawn by Kevin G. Shanks (2024)

The most recent data from the Drug Enforcement Administration’s (DEA) National Forensic Laboratory Information System in 2022 showed that the designer benzodiazepines clonazolam (5th), bromazolam (6th), etizolam (8th), flualprazolam (10th), and flubromazepam (14th) were now in the top 15 reported tranquilizers and depressants in the United States. Each of these compounds have been previously implicated in human intoxication cases involving driving motor vehicles as well as being involved in or associated with toxicity leading to fatality. 

Because of these trends, Axis recently introduced an all-encompassing Designer Benzodiazepines panel of testing. This panel scope includes adinazolam, bromazolam, clonazolam and metabolite 8-aminoclonazolam, etizolam, flualprazolam, flubromazepam, flubromazolam, gidazepam (as desalkylgidazepam). This streamlined panel allows for easier potential identification of designer benzodiazepines in your medical-legal investigation. 

As always, if you have questions about these substances and how they may apply to your toxicology casework or investigation, please reach out to our forensic toxicology experts by email ([email protected]) or phone (317-759-4869, Option 3).

By Kevin Shanks, M.S., D-ABFT-FT

To quantify or not? That is the question. If you regularly read forensic toxicology reports, then you know laboratory tests can be qualitative or quantitative. Qualitative tests only provide a positive/present or negative result.  Quantitative tests are tests that have a numerical result. So, why do we report some tests as qualitative and some as quantitative? There are a couple of different answers that resolve the question. 

Firstly, in forensic toxicology, blood is the gold standard when it comes to analytical testing as blood gives a snapshot of drug exposure and potential toxicity of circulating drugs in the window of a few minutes to several hours. Studies compile reference ranges or sets of blood drug or metabolite concentrations used as a guideline for interpreting results. These can normally be classified as therapeutic, toxic, and fatal ranges. Therapeutic blood concentration is the concentration of a drug or its active metabolite which is present in the blood following a therapeutic dosage of the drug. Most therapeutic ranges originate from data acquired during pharmaceutical medication human clinical trials or controlled dosing drug studies. Toxic blood concentration is the concentration of a drug, or its active metabolite, present in the blood that is associated with serious adverse symptoms. Fatal blood concentration is the concentration of a drug, or its active metabolite, present in the blood that has been reported to cause fatality or is so far above reported therapeutic or toxic concentrations, that one may judge it might cause fatality. Alternative matrices such as liver and brain tissue have very limited reference data available, and the availability is typically relegated to the classical drugs of abuse. Urine, on the other hand, gives a much wider window of drug detection – usually on the order of 1-5 days – but any drug or metabolite that is detected in urine is not imparting a pharmacological effect on the body. As urine is an excretory product, quantitative results do not and cannot correlate to or be associated with impairment, toxicity, or fatality. 

For those drugs that have clinical human trial data, for those drugs that have controlled dosing studies, and for those drugs that have established toxic and lethal reference ranges, quantitative testing is applicable. A forensic toxicologist can use the data and the established blood concentration ranges as a guide to aid in interpreting the analytical result and potentially come to an opinion on the role of a substance in an incident such as driving while impaired or the cause of death of an individual. On the other hand, alternative matrices such as tissue or urine may be reported as qualitative only due to the limited amount of reference data available or the nature of the specimen being a waste product. 

What about those substances that are new to the drug scene? What about those new street drugs or novel psychoactive substances (NPS)? We do not have human clinical trial data for these substances. We do not have controlled dosing studies for these substances. For some newly established compounds on the street, we may not even know their true pharmacological action in the body. What receptors do they bind to? How tightly do they bind to the receptor? What metabolites does the body produce? Are those metabolites active or inactive? What effects does the drug elicit? In a controlled setting, what blood concentrations are typically observed? Are those blood concentrations correlated to or with a specific effect or behavior or toxicity?  

There is a paucity of information when it comes to new drugs as well as alternative matrices. And for this reason, many laboratories will choose to report qualitative results only. When there is a lack of this quantitative reference data, the mere presence of the drug is the important part in the interpretation of the toxicology results. 

A second reason why a laboratory may choose to report qualitative results over quantitative results is two-fold – the extensive work and costs that goes in to developing and validating the analytical method to determine the result in the lab in combination with the rapidly changing illicit drug market. 

NPS such as fentanyl analogs, nitazene opioids, synthetic cannabinoids, and designer benzodiazepines ebb and flow as time goes on. They can appear and disappear rapidly over weeks to months. By the time the analytical method is validated and on-boarded to the laboratory, there is a good chance that the drugs that were prevalent on the market are no longer out there and have been replaced by other new drugs not in the newly updated method. 

As an example, for a while around 2015-2020, synthetic cannabinoids were prevalent in the USA and the street drug market was very rapidly changing. Compounds were emerging on the street, becoming prevalent, and then disappearing from the market within approximately a 3–6-month time span. In the span of a year or two, there were 10-20 new synthetic cannabinoids on the street. To either create a new quantitative test for these newly emerged substances or update a current test to include these new compounds, the development and validation process would take approximately 3-6 months. By the time the quantitative method was validated and approved for use in the laboratory, the entire drug scene on the street had changed and the new method was outdated. By validation protocols, qualitative tests are much quicker to validate than quantitative tests. So, as a forensic toxicology laboratory aiming to produce relevant (in time and scope) toxicology results in the aid of medical-legal investigations, it makes sense to develop qualitative tests for those newly emerged compounds. 

Ultimately, whether it is a qualitative test or a quantitative analysis – the interpretation of results hinges on the context and circumstances of the case. Axis Forensic Toxicology understands that one should never practice toxicology in a vacuum, and we are here to help with interpretation of the relevant toxicology in your casework. If you have any questions or concerns regarding a substance’s reference range or its role in your medical-legal investigation, please reach out to our subject matter experts at [email protected]. 

References 

Guidelines for the Interpretation of Analytical Toxicology Results. Disposition of Toxic Drugs and Chemicals in Man. Twelfth Edition. Randall C. Baselt. Biomedical Publications. Pages xxx-xlii. (2020).  

Pharmacokinetics and Pharmacodynamics. Principles of Forensic Toxicology. Fourth Edition. Barry Levine. American Association for Clinical Chemistry (AACC). 2017. 77-93. 

Introduction to Forensic Toxicology. Clarke’s Analytical Forensic Toxicology. Sue Jickells and Adam Negrusz. Pharmaceutical Press. Pages 1-12. (2008).  

Postmortem Toxicology. Clarke’s Analytical Forensic Toxicology. Sue Jickells and Adam Negrusz. Pharmaceutical Press. Pages 191-218. (2008).  

Postmortem Forensic Toxicology. Principles of Forensic Toxicology. Fourth Edition. Barry Levine. AACC, Inc. Pages 3-14. (2017). 

Reference Ranges. Axis Forensic Toxicology Blog. https://axisfortox.com/reference-ranges/ (2022).