Pyrazolam, also known as SH-I-04, is a benzodiazepine derivative initially developed by a research team led by Leo Sternbach at Hoffman-La Roche during the 1970s. This compound has experienced a resurgence and is now being marketed as a designer drug since 2012.

Pyrazolam exhibits structural resemblances to alprazolam and bromazepam. One notable characteristic that sets it apart from many other benzodiazepines is that it doesn’t seem to undergo metabolic processes, with the unchanged substance being excreted in the urine.

IUPAC name
CAS Number39243-02-2
PubChem CID12562545
Chemical and physical data
Molar mass354.211 g·mol−1

Legal status

In the United Kingdom, pyrazolam was categorized as a Class C drug under section 5 of the May 2017 modification to The Misuse of Drugs Act 1971, in line with several other designer benzodiazepine substances.


  • What is Pyrazolam?
  • Pyrazolam is a benzodiazepine derivative that was initially developed by a team led by Leo Sternbach at Hoffman-La Roche in the 1970s. It shares structural similarities with drugs like alprazolam and bromazepam.
  • How is Pyrazolam used?
  • Pyrazolam is often used recreationally, but it was initially developed for medical purposes. It has anxiolytic and sedative effects, which may make it attractive for people seeking relaxation or relief from anxiety.
  • Is Pyrazolam legal?
  • The legal status of Pyrazolam varies from one country to another. In some places, it is considered a controlled substance, while in others, it may not be explicitly regulated. It is essential to be aware of the specific laws in your region.
  • How does Pyrazolam differ from other benzodiazepines?
  • Pyrazolam is unique among benzodiazepines in that it does not appear to undergo significant metabolism in the body. Instead, it is primarily excreted unchanged in the urine.
  • What are the potential risks associated with Pyrazolam use?
  • Pyrazolam, like other benzodiazepines, can lead to dependence and withdrawal symptoms if used regularly and for extended periods. It can cause drowsiness, impaired coordination, and memory problems, especially at high doses.
  • Is Pyrazolam safe to use?
  • The safety of Pyrazolam, like many designer drugs, is not well-studied. It is essential to exercise caution and use it responsibly if you choose to do so. Misuse can lead to adverse effects, including addiction and health risks.
  • Is Pyrazolam available for medical use?
  • Pyrazolam is not widely used for medical purposes. It is primarily found in the context of research and recreational drug use.
  • Is it legal to buy Pyrazolam online?
  • The legality of purchasing Pyrazolam online depends on your location. It is essential to be aware of local laws and regulations, as buying and using designer drugs can have legal consequences.
  • Can Pyrazolam cause addiction or withdrawal symptoms?
  • Yes, like other benzodiazepines, Pyrazolam can lead to dependence if used regularly. Abrupt discontinuation after prolonged use may result in withdrawal symptoms such as anxiety, restlessness, and seizures.
  • Is Pyrazolam tested for in standard drug screenings?
  • Pyrazolam is not typically included in standard drug tests. However, specialized tests may detect its presence if specifically sought.


  1. Customs (Prohibited Imports) Regulations 1956 – Schedule 4, 1956: This regulation outlines restrictions on the importation of certain substances and goods, including designer drugs like Pyrazolam, in 1956. It’s essential to understand such regulations to avoid legal issues related to importing substances.
  2. Pharmacophore for the Alpha 5 GABA(A) Benzodiazepine Receptor Model: This research article reviews the updated pharmacophore for the Alpha 5 GABA(A) benzodiazepine receptor model. It’s crucial for understanding the pharmacological aspects of substances like Pyrazolam.
  3. US Patent 3954728: Issued to Hoffmann-La Roche Inc., this patent covers the preparation of triazolo benzodiazepines and novel compounds, providing historical context for Pyrazolam’s development.
  4. Characterization of Pyrazolam and Its Detectability: This study delves into the characterization of Pyrazolam and its detectability in human serum and urine. Understanding how Pyrazolam behaves in the body is vital for assessing its potential risks.
  5. Designer Benzodiazepines: A New Challenge: This publication discusses designer benzodiazepines like Pyrazolam, shedding light on the emerging challenges posed by these substances in the field of toxicology and public health.
  6. Detectability of Designer Benzodiazepines: The ability to detect designer benzodiazepines, including Pyrazolam, is explored in this research. This information is valuable for forensic and clinical purposes.
  7. Blood Concentrations of New Designer Benzodiazepines: Research into the blood concentrations of new designer benzodiazepines provides insights into their presence in forensic cases, which can inform legal and regulatory decisions.
  8. Experimental versus Theoretical Values for Benzodiazepines: Understanding the disparities between experimental and theoretical values for properties like log D7.4, pKa, and plasma protein binding of benzodiazepines, including Pyrazolam, is crucial for accurate assessments.
  9. Blood-to-Plasma Ratio and Predicted GABAA-Binding Affinity: This research explores the blood-to-plasma ratio and predicted GABAA-binding affinity of designer benzodiazepines, enhancing our knowledge of their pharmacological effects.
  10. Central Nervous System Depressant Activity of 6-phenyl-4H-s-triazolo[4,3-a][1,4]benzodiazepines: A study conducted in November 1971, investigating the central nervous system depressant activity of compounds with structural similarities to Pyrazolam.
  11. The Misuse of Drugs Act 1971 (Amendment) Order 2017: This legal order, part of the Misuse of Drugs Act, highlights changes in drug classifications, including designer benzodiazepines like Pyrazolam, in 2017. Understanding such legal amendments is essential to stay compliant with drug regulations in the UK.

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