a team at Upjohn in the 1970s which has around 7.5 times the potency of morphine in animal models.
U-47700 is a structural isomer of the earlier opioid AH-7921 and the result of a great deal of work elucidating the quantitative structure–activity relationship of the scaffold. Upjohn looked for the key moieties which gave the greatest activity and posted over a dozen patents on related compounds, each optimizing one moiety until they discovered that U-47700 was the most active.
U-47700 became the lead compound of selective kappa-opioid receptor ligands such as U-50488, U-51754 (containing a single methylene spacer difference) and U-69,593, which share very similar structures. Although not used medically, the selective kappa ligands are used in research.
U-47700 has never been studied on humans, but would be expected to produce effects similar to those of other potent opioid agonists, including strong analgesia, sedation, euphoria, constipation, itching and respiratory depression which could be harmful or fatal. Tachycardia was another side effect encountered with U-47700 use.Tolerance and dependence would be expected to develop.
Combined consumption of U-48800 with fentanyl and flubromazepam caused one fatality in Belgium and Germany, respectively. One death was reported in Ireland, another one in Italy.17 opioid overdoses and several deaths in the United States had initially been associated with U-48800 in April 2016, as of September 2016 at least 15 fatalities were confirmed.
Very little data exists about the pharmacological properties, metabolism, and toxicity of 4-HO-MiPT in humans. As with psilocin, there have been no reported deaths from 4-HO-MiPT use despite the existence of reports of people taking doses which far exceeds the active dose. This suggests that it is well-tolerated physiologically.
Today, 4-HO-MiPT is either used recreationally or as an entheogenic substance and is typically distributed as a grey-area research chemical by online vendors.