Mecloqualone is a quinazoline-class GABAergic and an analog of methaqualone. It acts as an agonist of the beta subtype of GABAa receptor and induces sedative, hypnotic and anxiolytic effects. Mecloqualone was marketed (mostly in france) under the names Nubrene and Casfen for the treatment of insomnia. Mecloqualone is no longer prescribed because of concerns about its potential for abuse and overdose. In the United States, it is registered as a Schedule-I non-narcotic controlled substance.

Eticyclidine (N-ethyl-1-phenylcyclohexylamine) is a phencyclidine derivative exerting nearly the same pharmacological profile as the parent compound. In rodents, it induces stereotypy, ataxia, interoceptive effect and hypothermia.

Etonitazene is a potent and selective mu-opioid agonist. It was developed in CIBA. Administration of etonitazene may induce respiratory depression, and therefor etonitazene is not used in humans. Etonitazene is explicitly listed as an illegal drug under UN convention and is illegal throughout the world.

Carfentanil is a synthetic fentanyl analog. It is a mu-opioid receptor agonist with an estimated analgesic potency approximately 10,000 times that of morphine and 20-30 times that of fentanyl, based on animal studies. Receptor binding studies have shown that carfentanil binds selectively and competitively to the μ subtype of opioid receptors relative to δ and κ opioid receptors. Preclinical studies have demonstrated that the pharmacodynamic effects, such as analgesia and constipation, produced by carfentanil are similar to other μ opioid agonists. Its extreme potency and propensity to produce rapid and profound respiratory depression has prompted recommendations that an opioid antagonist, such as naloxone or naltrexone, be available whenever carfentanil is used or suspected to be present. Carfentanil (Wildnil) has been used in veterinary as a prescription-only general anesthetic for intramuscular injection in large animals. Carfentanil is no longer FDA-approved for use in animals after Wildlife Laboratories withdrew the application for Wildnil. Carfentanyl is increasingly involved in opioid overdose deaths among illicit opioid users.

ORG-28611 (SCH-900,111) is a potent cannabinoid receptor full agonist, developed by Organon International for treatment pain. In preclinical studies, Org 28611 exhibited high affinity for both CB1 and CB2 cannabinoid receptors, as determined by radioligand competition binding assays and rapidly metabolized by mouse and human hepatic microsomes and showed higher total levels in the brain compared to plasma. In clinical trials, Org 28611 does not provide enough sedation for outpatient surgical procedures, does not induce anterograde amnesia and causes undesirable subjective effects at higher doses. However, bolus doses up to 3 μ/kg (with maximum initial plasma concentrations of 24 ng/mL) or mean plasma levels up to 4 ng/mL are well tolerated and make it worthwhile to further explore the analgesic or antiemetic properties.

Desmethylmoramide is a morpholinopyrrolidine. Being opioid receptor agonist it might be used as narcotic analgesic.

Lofentanil is a pure mu-opioid receptor agonist derived from fentanyl. It is the most potent opioid to be administered to humans, about 500-1000 times more potent than morphine. Lofentanil provides a higher affinity quotient with longer dissociation times for the mu-receptors than fentanyl. The clinical study of the compound is difficult because there is a very individual sensibility. The appropriate doses are not easy to evaluate. Reversal of the loventanil depression needs very high and repeated naloxone dose. Practical use of lofentanil is limited. Lofentanil side effects are: nausea, vomiting and sedation.

Midafotel (CPPene; SDZ EAA 494) is a selective competitive antagonist at the N-methyl-D-aspartate (NMDA) subtype of glutamate receptor. It was originally designed as a potential therapy for excitotoxicity, epilepsy or neuropathic pain. Midafotel had been in phase III clinical trials by Novartis for the treatment of brain injury. However, this research has been discontinued.

Brolamfetamine (also known as DOB, bromo-DMA, and 4-bromo-2,5-dimethoxyphenylisopropylamine) is one of a vast number of compounds used recreationally to achieve hallucinogenic effects. Brolamfetamine is one of the most potent hallucinogens, with its hallucinogenic potency directly linked to its abuse potential. Brolamfetamine acts as a partial agonist of 5HT2A, 5HT2B, 5HT2C, and TAAR1 receptors, but it’s psychedelic effects are mainly mediated by its agonistic properties at the 5-HT2A receptor. Animal studies have shown physiologic effects including hypertension, tachycardia, hyperpyrexia, pupillary dilatation, and peripheral vasoconstriction. In general, Brolamfetamine having a similar effect to LSD, with slower onset (up to 3–4 h to peak intoxication) and longer duration of effect (up to 36 h). Brolamfetamine is not commonly available, through periods of higher circulation were reported in Australia in 1983, Ireland in 2003, and in Italy in 2015. Brolamphetamine, as well as many other synthetic hallucinogens, are increasingly being sold as LSD. Internationally Brolamfetamine is a Schedule I drug under the Convention on Psychotropic Substances. Due to its selectivity, Brolamfetamine is often used in scientific research when studying the 5-HT2 receptor subfamily.

Dizocilpine (MK-801) is an antagonist of the N-methyl-D-aspartate (NMDA) receptor in the glutamate category involved with the central nervous system (CNS). The drug displays a variety of physiological actions, many of which involve the CNS, such as anesthetic and anticonvulsant properties. It penetrates readily into CNS and was described as the agent with central sympathomimetic properties. Co-administration of dizocilpine with psychostimulants, such as cocaine, amphetamine and nicotine, has been reported to prevent the development of behavioural sensitization to these drugs as well as associated neuroadaptations in rodents. However, studies with bromocriptine have suggested that co-administration of dizocilpine might merely cause sensitization to become state-dependent. A single injection of MK-801 to rats models both positive and negative symptoms of schizophrenia. Treatment of mice with dizocilpine induced learning impairment.