Diphenpipenol, a synthetic opioid analgesic, emerged in the 1970s through the innovative work of Dainippon Pharmaceutical Co.Structurally, it belongs to the class of 1-substituted-4-(1,2-diphenylethyl)piperazine derivatives, sharing similarities with compounds like MT-45 and AD-1211. Notably, within this group, diphenpipenol stands out as the most potent compound. In animal studies, the (S) enantiomer, in particular, exhibits remarkable potency, surpassing morphine by a factor of approximately 105 times.
This extraordinary potency places diphenpipenol on par with fentanyl and its analogs in terms of strength. Consequently, the use of diphenpipenol carries a substantial risk of inducing life-threatening respiratory depression, along with the customary side effects associated with opioids, such as sedation, itching, nausea, and vomiting.
It is worth noting that diphenpipenol has surfaced on the online market as a designer drug. However, upon analyzing a sample presumed to be diphenpipenol, it was found to contain a structural isomer with significantly weaker opioid activity. This discovery casts doubt on whether genuine diphenpipenol has indeed been available for sale.

IUPAC name
CAS Number83374-54-3 
PubChem CID13236269
Chemical and physical data
Molar mass388.511 g·mol−1


  • What is Diphenpipenol?
  • Diphenpipenol is a synthetic opioid analgesic that was developed in the 1970s by Dainippon Pharmaceutical Co. It is chemically classified as a 1-substituted-4-(1,2-phenylmethyl)piperazine derivative and is known for its exceptionally high potency compared to other opioids.
  • How does Diphenpipenol work?
  • Diphenpipenol functions by binding to opioid receptors in the brain and spinal cord, effectively reducing the perception of pain. Its potent analgesic properties make it a sought-after substance in the field of pain management.
  • Is Diphenpipenol available for medical use?
  • As of my knowledge, the cutoff date in September 2021; Diphenpipenol has not been approved for medical use in most countries. It was primarily a research compound.
  • What makes Diphenpipenol unique among opioids?
  • Diphenpipenol stands out due to its extraordinary potency, with the (S) enantiomer being about 105 times more potent than morphine in animal studies. This makes it comparable in strength to fentanyl, a powerful opioid.
  • What are the risks associated with Diphenpipenol use?
  • Using Diphenpipenol carries a significant risk of causing life-threatening respiratory depression, which is a common concern with potent opioids. Users may also experience side effects typical of opioids, such as sedation, itching, nausea, and vomiting.
  • Is Diphenpipenol sold as a designer drug?
  • Yes, there have been reports of Diphenpipenol being offered for sale as a designer drug, mainly through online channels. However, it’s important to note that analysis of some supposed Diphenpipenol samples has revealed the presence of structural isomers with much weaker opioid activity, raising questions about the authenticity of the product.
  • Is Diphenpipenol legal to possess or use?
  • The legal status of Diphenpipenol may vary by country and is subject to change over time. It is crucial to be aware of the local regulations and laws pertaining to this substance in your area. Misuse or possession of Diphenpipenol may have legal consequences.
  • Is there any known medical application for Diphenpipenol?
  • As of my last knowledge update in September 2021, Diphenpipenol has not been approved for any medical applications. Its use, if any, would have been limited to research settings.
  • What precautions should one take if they encounter Diphenpipenol?
  • If you come across Diphenpipenol or products claiming to contain it, exercise caution. Given the potential risks and uncertainties surrounding its authenticity, it’s advisable to avoid using it. Consult with a healthcare professional if you have any concerns or questions about this substance.


  1. US Patent 4080453: On March 21, 1978, the United States Patent 4080453 was issued for the invention titled “1-Substituted-4-(1,2-diphenylethyl)piperazine Derivatives and Compositions Containing the Same.” This patent was assigned to Dainippon Pharmaceutical Co Ltd, highlighting their pioneering work in this area.
  2. Research on Piperazine Derivatives: In October 1987, an influential study by Natsuka K, Nakamura H, Nishikawa Y, Negoro T, Uno H, and Nishimura H was published. This research delved into the “Synthesis and Structure-Activity Relationships of 1-Substituted 4-(1,2-diphenylethyl)piperazine Derivatives Having Narcotic Agonist and Antagonist Activity.” The findings were published in the Journal of Medicinal Chemistry, Volume 30, Issue 10, spanning pages 1779 to 1787. The study provided valuable insights into the pharmacological properties of these derivatives.
  3. Exploring a Novel Opioid NPS: In June 2020, an intriguing report was published by Cannaert A, Hulpia F, Risseeuw M, Van Uytfanghe K, Deconinck E, and Van Calenbergh S. This report discussed a “New Opioid NPS” and offered a comprehensive analysis of its chemical composition and in vitro functional characteristics. Notably, this compound was a structural isomer of the MT-45 derivative known as diphenpipenol. The study was published in the Journal of Analytical Toxicology, Volume 45, Issue 2, spanning pages 134 to 140. The publication can be accessed via DOI: 10.1093/jat/bkaa066, and it was indexed with PMID 32514558. This research shed light on a substance with potential implications for the field of toxicology.

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