Both methamphetamine and dextromethamphetamine are illicitly
trafficked and sold owing to their potential for recreational use. The highest
prevalence of illegal methamphetamine use occurs in parts of Asia, Oceania, and
in the United States, where racemic methamphetamine, levomethamphetamine, and
dextromethamphetamine are classified as schedule II controlled substances.
Levomethamphetamine is available as an over-the-counter (OTC) drug for use as an inhaled nasal decongestant in the United States.[note 3] Internationally,
the production, distribution, sale, and possession of methamphetamine is
restricted or banned in many countries, due to its placement in schedule II of
the United Nations Convention on
Psychotropic Substances treaty.
While dextromethamphetamine is a more potent drug, racemic methamphetamine is
sometimes illicitly produced due to the relative ease of synthesis and limited availability of chemical precursors.
In low doses, methamphetamine can elevate mood,
increase alertness, concentration and energy in fatigued individuals, reduce
appetite and promote (initial) weight loss. At higher doses, it can induce psychosis, breakdown of
skeletal muscle, seizures and bleeding in the brain. Chronic high-dose use
can precipitate unpredictable and rapid mood swings,
prominent delusions and violent behavior.
Recreationally, methamphetamine's ability to increase energy has been reported to lift mood andincrease sexual
desire to such an
extent that users are able to engage in sexual activity continuously for
several days.[17] Methamphetamine
is known to have a highaddiction liability
(i.e. compulsive methamphetamine use) and dependence liability
(i.e. withdrawal symptoms occur when methamphetamine
use ceases). Heavy recreational use of methamphetamine may lead to a post-acute-withdrawal syndrome, which can
persist for months beyond the typical withdrawal period. Unlikeamphetamine,
methamphetamine is neurotoxic to human midbrain dopaminergic neurons.[18] It has
also been shown to damage serotonin neurons in the CNS.[19][20]This
damage includes adverse changes in brain structure and function, such as
reductions in grey matter volume in several brain regions and
adverse changes in markers of metabolic integrity.[20]
Methamphetamine belongs to the substituted phenethylamine and substituted amphetamine chemical classes. It is related to the
other dimethylphenethylamines as apositional
isomer of these
compounds, which share the common chemical formula: C10H15N1.
Medical
In the United States, methamphetamine hydrochloride, under the
trade name Desoxyn, has
been approved by the FDA for treating ADHD and obesity in
both adults and children;[21][22] however, the FDA also indicates that the
limited therapeutic usefulness of methamphetamine should be weighed against the
inherent risks associated with its use.[21] Methamphetamine is sometimes prescribed off label for narcolepsy and idiopathic hypersomnia.[23][24] In the United States, methamphetamine's levorotary form is
available in some over-the-counter (OTC) nasal decongestant products.[note 3]
As methamphetamine is associated with a high potential for
misuse, the drug is regulated under the Controlled Substances Act and is listed under schedule II in the
United States.[21] Methamphetamine hydrochloride dispensed
in the United States is required to include a boxed warning regarding
its potential for recreational misuse and addiction liability.[21]
Recreational
See also: Party and play and
the Recreational routes of
methamphetamine administration
Methamphetamine is often used recreationally for its effects as
a potent euphoriant and stimulant as well as aphrodisiac qualities.[17] According to a National GeographicTV documentary on
methamphetamine, "an entire subculture known as party and play is
based around methamphetamine use".[17] Members of this San Francisco
sub-culture, which consists almost entirely of gay male methamphetamine users,
will typically meet up through internet dating sites and have sex.[17] Due to its strong stimulant and
aphrodisiac effects and inhibitory effect on ejaculation,
with repeated use, these sexual encounters will sometimes occur continuously
for several days on end.[17] The crash following the use of
methamphetamine in this manner is very often severe, with marked hypersomnia (excessive
daytime sleepiness).[17]Methamphetamine use has also been noted among
men having sex with men in New York City.[25]
Contraindications
Methamphetamine is contraindicated in individuals with a
history of substance use
disorder, heart disease, or
severe agitation or
anxiety, or in individuals currently experiencing arteriosclerosis, glaucoma,hyperthyroidism, or severe hypertension.[21] The USFDA states that individuals who have experienced hypersensitivity reactions to other
stimulants in the past or are currently taking monoamine
oxidase inhibitorsshould not take methamphetamine.[21] The USFDA also advises individuals with bipolar disorder, depression,
elevated blood pressure,
liver or kidney problems, mania, psychosis, Raynaud's phenomenon, seizures,thyroid problems, tics,
or Tourette syndrome to
monitor their symptoms while taking methamphetamine.[21] Due to the potential for stunted growth, the USFDA advises
monitoring the height and weight of growing children and adolescents during
treatment.[21]
Side effects
- Physical
The physical effects of methamphetamine can include loss of appetite,
hyperactivity, dilated pupils, flushed skin, excessive sweating, increased movement,
dry mouth and teeth grinding (leading
to "meth mouth"), headache, irregular heartbeat (usually as accelerated heartbeat or slowed heartbeat), rapid breathing, high blood pressure, low blood pressure, high body temperature, diarrhea, constipation, blurred vision,dizziness, twitching, numbness, tremors, dry skin, acne,
and pale appearance.[21][26] Methamphetamine that is present in a mother's bloodstream can pass through the placenta to a fetus and
can also be secreted into breast milk.[27] Infants born to methamphetamine-abusing mothers were found
to have a significantly smaller gestational age-adjusted head
circumference and birth weight measurements.[27] Methamphetamine exposure was also associated with neonatal withdrawal symptoms
of agitation, vomiting and fast breathing.[27] This withdrawal syndrome is relatively mild and only
requires medical intervention in approximately 4% of cases.[28]
- Meth mouth
Main article: Meth mouth
Methamphetamine users and addicts may lose their teeth
abnormally quickly, regardless of the route of administration, from a condition
informally known as meth mouth.[29] The condition is generally most severe in users who inject
the drug, rather than swallow, smoke, or inhale it.[29] According to the American Dental
Association, meth mouth "is probably caused by a combination of
drug-induced psychological and physiological changes resulting in xerostomia (dry mouth), extended periods
of poor oral hygiene,
frequent consumption of high-calorie, carbonated beverages and bruxism (teeth grinding and
clenching)".[29][30] As dry mouth is also a common side effect of other
stimulants, which are not known to contribute severe tooth decay, many
researchers suggest that methamphetamine associated tooth decay is more due to
users' other choices. They suggest the side effect has been exaggerated and
stylized to create a stereotype of current users to deter new ones.[31]
- Sexually transmitted infection
Methamphetamine use was found to be related to higher frequencies of unprotected sexual intercourse in both HIV-positive and unknown casual partners, an association more pronounced in HIV-positive participants.[32] These findings suggest that methamphetamine use and engagement in unprotected anal intercourse are co-occurring risk behaviors, behaviors that potentially heighten the risk of HIV transmission among gay and bisexual men.[32] Methamphetamine use allows users of both sexes to engage in prolonged sexual activity, which may cause genital sores and abrasions as well as priapism in men.[21][33]Methamphetamine may also cause sores and abrasions in the mouth via bruxism, increasing the risk of sexually transmitted infection.[21][33]
Besides the sexual transmission of HIV, it may also be
transmitted between users who share a common needle.[34] The level of needle sharing among methamphetamine users is
similar to that among other drug injection users.[34]
- Psychological
The psychological effects of methamphetamine can include euphoria, dysphoria, changes in libido, alertness, apprehension and concentration, decreased sense of fatigue, insomnia or wakefulness, self-confidence, sociability, irritability,
restlessness, grandiosity and repetitive and
obsessive behaviors.[21][26][35] Methamphetamine use also has a high association with anxiety, depression, amphetamine psychosis, suicide, and violent behaviors.[36]
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