Levamisole, Aminorex, and Pulmonary Arterial Hypertension: A Review

DARK Classics in Chemical Neuroscience: Aminorex Analogues

Aminorex (5-phenyl-4,5-dihydro-1,3-oxazol-2-amine) and 4-methylaminorex (4-methyl-5-phenyl-4,5-dihydro-1,3-oxazol-2-amine) are psychostimulants that have long been listed in Schedules IV and I of the UN Convention on Psychotropic Substances of 1971. However, a range of psychoactive analogues exist that are not internationally controlled and therefore often classified as new psychoactive substances (NPS). Aminorex analogues encompass failed pharmaceuticals that reemerged as drugs of abuse, and newly synthesized substances that were solely designed for recreational use by clandestine chemists. NPS, sometimes also referred to as "designer drugs" in alignment with a phenomenon arising in the early 1980s, serve as alternatives to controlled drugs. Aminorex and its derivatives interact with monoaminergic neurotransmission by interfering with the function of monoamine transporters. Hence, these compounds share pharmacological and neurochemical similarities with amphetamines and cocaine. The consumption of aminorex, 4-methylaminorex and 4,4'-dimethylaminorex (4-methyl-5-(4-methylphenyl)-4,5-dihydro-1,3-oxazol-2-amine) has been associated with adverse events including death, bestowing an inglorious fame on aminorex-derived drugs. In this Review, a historical background is presented, as well as an account of the pharmacodynamic and pharmacokinetic properties of aminorex and various analogues. Light is shed on their misuse as drug adulterants of well-established drugs on the market. This Review not only provides a detailed overview of an abused substance-class, but also emphasizes the darkest aspect of the NPS market, i.e., deleterious side effects that arise from the ingestion of certain NPS, as knowledge of the pharmacology, the potency, or the identity of the active ingredients remains obscure to NPS users.

Levamisole in Illicit Trafficking Cocaine Seized: A One-Year Study

Cocaine use is increasing around the world and its purity is frequently altered through dilution, substitution, contamination, and adulteration. Sugars, talc, starch, and carbonates represent the principal diluents of cocaine, while phenacetin, levamisole, caffeine, and lidocaine are its major adulterants in Europe. Levamisole is used because it is an odorless powder, with physical properties similar to cocaine, and it has reasonable cost and availability, being widely used in veterinary medicine. For this study, we analyzed 88 cocaine samples. The seized cocaine analyzed showed an average purity of 55% and the most frequent adulterants identified were: levamisole (31.8%), caffeine (6.8%), lidocaine (2.3%), acetaminophen (2.3%), and phenacetin (1.1%). Our aim is the study of the presence of levamisole, over other adulterants in seized cocaine samples, due to its recognized human toxicity. The chronic use of levamisole-adulterated cocaine represents a serious public health issue because it may be responsible for side-effects such as dermal vasculopathy, leukoencephalopathy, leukopenia, agranulocytosis, pulmonary hemorrhage, multiple emboli, and several other effects. Moreover, aminorex can cause idiopathic pulmonary hypertension, presenting another harmful and mostly lethal side-effect from cocaine cut with levamisole. In conclusion, levamisole determination should be performed in routine toxicological analysis in deaths due to cocaine use.