Didiavalo (premethadone) is a methadone analog and precursor. Didiavalo possesses analgetic properties with the effective dose in rats 30 times higher than the analgesic dose of morphine.

Nabilone is a synthetic cannabinoid approved under the brand name cesamet for treatment of severe nausea and vomiting associated with cancer chemotherapy. Nabilone is an orally active which, like other cannabinoids, has complex effects on the central nervous system (CNS). It has been suggested that the antiemetic effect of nabilone is caused by interaction with the cannabinoid receptor system, i.e. the CB (1) receptor, which has been discovered in neural tissues.

Piminodine is an analog of pethidine. It was used in medicine for obstetric analgesia and in dental procedures briefly during the 1960s and 1970s, but has largely fallen out of clinical use. Piminodine produces analgesia, sedation and euphoria and has typical side effects associated with opioids, including potentially serious respiratory depression, which can be life-threatening. Piminodine was more potent than desipramine and protriptyline under similar conditions. Compared to meperidine, piminodine is more potent and gives smoother duration. Piminodine can be addictive. Piminodine is currently a Schedule II controlled substance in the United States.

(-)-Phenazocine is an opioid analgesic drug, which is related to pentazocine and has a similar profile of effects. (-)-Phenazocine is a potent mu opioid receptor agonist. In addition, (−)-phenazocine is also known to bind to δ opioid receptors (DOR) and κ opioid receptors (KOR). Regarding their analgesic potency, (−)-phenazocine was twenty times more potent than morphine in the hot plate test and sixty times more potent than its dextro enantiomer when it was subcutaneously (s.c.) administered

Aniledrine is a narcotic pain reliver. The drug was prescribed as an analgesic in anaesthesia (Leritine brand name), however, it is no longer available on the market. Although the exact mechanism is not fully understood, aniledrine appears to elicit its action by binding to endorphine receptors in CNS.

Glutethimide is a GABA agonist that was introduced by Ciba in 1954 as a safe alternative to barbiturates to treat insomnia. Before long, however, it had become clear that glutethimide was just as likely to cause addiction and caused similarly severe withdrawal symptoms. Glutethimide was discontinued in the US by manufacturers in 1993. Current production levels in the United States point to it only being used in small-scale research.

Dihydrocodeine is an opioid analgesic used as an alternative or adjunct to codeine to treat moderate to severe pain, severe dyspnea, and cough. It is semi-synthetic, and was developed in Germany in 1908 during an international search to find a more effective antitussive agent to help reduce the spread of airborne infectious diseases such as tuburculosis. It was marketed in 1911. Dihydrocodeine is metabolized to dihydromorphine -- a highly active metabolite with a high affinity for mu opioid receptors. Dihydrocodeine is used for the treatment of moderate to severe pain, including post-operative and dental pain. It can also be used to treat chronic pain, breathlessness and coughing. In heroin addicts, dihydrocodeine has been used as a substitute drug, in doses up to 2500mg/day to treat addiction.