Dimenoxadol is an opioid analgesic which produces typical opioid effects such as analgesia and sedation. It is structurally similar to methadone and is a benzilic acid derivative. In the United States it is classified as a Schedule I controlled drug.

Carsalam is a nonsteroidal anti-inflammatory compound and platelet aggregation inhibitor.

Salacetamide is a derivative of salicylic acid. It is analgesic, anti-inflammatory and antipyretic agent.

There is no much information related to the pharmacological and/or biological properties of parapropamol. However, the analgesic properties of this compound had been studied in dentistry.

Pravadoline is the anti-nociceptive agent, which has analgesic efficacy against postoperative pain in humans. Pravadoline inhibits the enzyme cyclooxygenase, but in contrast to cyclooxygenase-inhibiting NSAIDs does not produce gastrointestinal irritation. Pravadoline inhibited the synthesis of prostaglandins in mouse brain both in vitro and ex vivo. Pravadoline demonstrated only weak anti-inflammatory activity relative to its anti-nociceptive potency. Single doses of pravadoline were safe and effective in humans, without serious adverse events. Single oral administration of pravadoline maleate induced acute tubular necrosis in male and female beagle dogs.

Frakefamide is a tetrapeptide with an amide function at the C-terminus. The amino acid sequence of frakefamide is L-tyrosyl-D-alanyl-p-fluoro-L-phenylalanyl-Lphenylalaninamide. Hence, it contains both natural and unnatural R-amino acids. Frakefamide has shown interesting properties for use in acute and chronic pain treatment. It acts as a selective agonist on mu-opioid receptors and belongs to the dermorphin peptide family. It has been shown to be a potent peripherally acting analgesic in rats and humans. However, frakefamide had been found to have "unexpected results" in Phase II trials and AstraZeneca offered to hand the drug back.

Nicotredole (Tryptamide), similarly to ibuprofen and piroxicam, shows anti-inflammatory and analgesic properties. Tryptamide reversed pyrogen-induced hyperthermia in rats, elicited analgesic effects in rats, but not in mice, prolonged the time of hexobarbital sleep in rats and inhibited locomotor activity in rats and mice. Tryptamide has not elicited side effects on the circulatory system of rats and cats.

Desomorphine is the common name for 4,5--epoxy-17- methylmorphinan-3-ol or dihydrodesoxymorphine-D. It is an opioid analogue and morphine derivative in which the 6-hydroxyl group and the double bond at carbons 7 and 8 of morphine are reduced. Desomorphine can cross the blood–brain barrier, binding to opioid receptors, similar to the pharmacokinetic distribution of all phenanthrene-structured alkaloids. Taking Desomorphine causes euphoria as well as sedative and analgesic relief. In addition to its faster onset than other powerful painkillers drugs such as morphine, desomorphine also initiates less sedative effects and seems to have favorable postoperative results, such as reduced need for catheterization, less dizziness, and decreased vomiting incidence. In comparison with Morphine, Desomorphine is faster reduced. It follows that it has to be taken it more frequently to get the same effects. Furthermore, it causes side effects such as respiratory and gastrointestinal problems and increased blood pressure. In addition, Desomorphine’s withdrawal symptoms are up to three times longer than Morphine’s. This leads to the conclusion that Desomorphine is more addictive. At present, desomorphine is classified as a narcotic drug (DEA code number 9055) in Schedule I of the U.S. Controlled Substances Act and is listed as a controlled substance under the international Single Convention on Narcotic Drugs of 1961.

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.

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.