Phenmetrazine is an anti-obesity drug, which was discovered by Boehringer-Ingelheim in 1952 and approved by FDA under the name Preludin. Later on the drug was withdrawn from the market due to the reported cases of abuse. According to some studies, misuse of phenmetrazine turned many young addicts to crime. It is suggested that the drug exerts its effect by inhibiting the monoamine transport.

Racemorphan is racemic mixture of an antitussive and dissociative hallucinogen Dextrorphan and an opioid analgesic Levorphanol. Racemorphan itself is under international control per the Single Convention on Narcotic Drugs 1961 and is therefore listed as a Schedule II Narcotic controlled substance.

ALPHAPRODINE is an opioid analgesic. It was used in obstetrics, as pre-operative medication, and for minor surgical procedures. In addition, this drug was used in the dentistry setting to help effectively manage pain associated with dental procedures.

Metopon was developed as an analgesic opium derivative. This drug has a high affinity to the mu-opioid receptor and produces antinociception through this receptor. Metopon was available in Canada only in tablet form for oral administration; however, because of the drug addiction, the Drug Addiction Committee recommended its limited use.

Secobarbital sodium, a barbiturate, is FDA approved for the treatment of insomnia and for pre-anesthetic use. This drug binds at a distinct site associated with a Cl- ionopore at the GABAA receptor, increasing the duration of time for which the Cl- ionopore is open. The post-synaptic inhibitory effect of GABA in the thalamus is, therefore, prolonged. Adverse reactions are drowsiness, lethargy, hangover, paradoxical excitement in elderly patients, somnolence. Rifampin may decrease secobarbital levels by increasing metabolism.

AMOBARBITAL is a barbiturate derivative with hypnotic and sedative properties. In an in vitro study in rat thalamic slices amobarbital worked by activating GABAA receptors, which decreased input resistance, depressed burst and tonic firing, especially in ventrobasal and intralaminar neurons, while at the same time increasing burst duration and mean conductance at individual chloride channels; this increased both the amplitude and decay time of inhibitory postsynaptic currents. Adverse effects are mainly a consequence of dose-related CNS depression and the risk of dependence with continued use is high.

Ethylmorphine is a derivative of morphine with analgesic and antitussive effect. It acts by activating the opioid receptors and thus has a direct influence on the CNS system. Ethylmorphine was approved in Europe for the treatment of dry cough (Codethyline, Dionine).

Levomethadyl acetate (LAAM) is a synthetic opioid agonist with actions qualitatively similar to morphine (a prototypic mu agonist) and affecting the central nervous system (CNS) and smooth muscle. Principal actions include analgesia and sedation. Tolerance to these effects develops with repeated use. An abstinence syndrome generally occurs upon cessation of chronic administration similar to that observed with other opiates, but with slower onset, more prolonged course, and less severe symptoms. LAAM exerts its clinical effects in the treatment of opiate abuse through two mechanisms. First, LAAM cross-substitutes for opiates of the morphinetype, suppressing symptoms of withdrawal in opiate-dependent individuals. Second, chronic oral administration of LAAM can produce sufficient tolerance to block the subjective “high” of usual doses of parenterally administered opiates. Since the introduction of levomethadyl in 1995, the manufacturer has received increasing reports of severe cardiac-related adverse events, including QT interval prolongation, Torsades de Pointes and cardiac arrest. Other cardiac-related adverse events have also been reported, including arrhythmias, syncope, and angina. These events led to the removal of levomethadyl from the European market in March 2001. A very small number of patients may benefit from levomethadyl, but the risk of continued distribution and use no longer outweighs the overall benefits.

Metazocine is a synthetic opioid analgesic with reinforcing properties and PCP-like activity. Metazocine is a Schedule II controlled substance. Metazocine acts as a ligand at opioid, sigma and NMDA receptors. Metazocine enantiomers exert different pharmacological activity.