|Systematic (IUPAC) name|
|Trade names||Vicks VapoInhaler|
Medical: Inhalation (nasal)
Recreational: Oral, intravenous, insufflation, inhalation, suppository
|CAS Registry Number|
Levomethamphetamine[note 1] is the levorotary (L-enantiomer) form of methamphetamine. Levomethamphetamine is a sympathomimetic vasoconstrictor which is the active ingredient used in some over-the-counter nasal decongestants including the US formulation of Vicks VapoInhaler, but not the Canadian or Indian formulations, which contain only menthol and camphor.
Levomethamphetamine is a TAAR1 agonist, so it affects the central nervous system, although its effects are weaker and somewhat shorter than those of dextromethamphetamine; it is not thought to possess the same addiction potential as that of racemic methamphetamine or dextromethamphetamine. Among its few physiological effects are the vasoconstriction that makes it useful for nasal decongestion. The elimination half-life of levomethamphetamine is between 13.3 and 15 hours, whereas dextromethamphetamine has a half-life of about 10.5 hours.
SelegilineLevomethamphetamine is the chemical precursor of the antiparkinson's drug selegiline. Selegiline, a selective monoamine oxidase B (MAOB) inhibitor,[note 2] is also metabolized into levomethamphetamine and levoamphetamine. This has caused users to test positive for amphetamines.
Selegiline itself has neuroprotective and neuro-rescuing effects, but concern over the resulting levomethamphetamine's neurotoxicity[note 3] led to development of alternative MAOB inhibitors such as rasagiline, that do not produce toxic metabolites.
When the nasal decongestant is taken in excess, levomethamphetamine has potential side effects resembling those of other sympathomimetic drugs; these effects include hypertension (elevated blood pressure), tachycardia (rapid heart rate), nausea, stomach cramps, dizziness, headache, and tremors.
In a study of psychoactive effects of levomethamphetamine, the intravenous administration of 0.5 mg/kg (but not 0.25 mg/kg) in recreational methamphetamine users produced scores of "drug liking" similar to racemic methamphetamine, but the effects were shorter lived. The study did not test the oral administration of levomethamphetamine. Currently there are no studies demonstrating "drug liking" scores of oral levomethamphetamine that are similar to racemic methamphetamine or dextromethamphetamine in either recreational users or medicinal users.
- Other names include l-methamphetamine, levodesoxyephedrine, l-desoxyephedrine, levmetamfetamine (INN and USAN)
- It is a selective MAOB inhibitor at normal clinical doses. MAOB is an enzyme that metabolizes dopamine, the neurotransmitter deficient in Parkinson's Syndrome.
- And neurotoxicity of other metabolites.