Methamphetamine

Methamphetamine
The skeletal formula of methamphetamine
Chemical Nomenclature
Common names	Meth, Methamphetamine, Speed
Systematic name	N-methyl-1-phenylpropan-2-amine
Class Membership
Psychoactive class	Stimulant
Chemical class	Amphetamine
Routes of Administration
Smoked Dosage WARNING: Always start with lower doses due to differences between individual body weight, tolerance, metabolism, and personal sensitivity. See responsible use section. DISCLAIMER: PW's dosage information is a summary of data gathered from users and resources. It is not a recommendation and should be verified with other sources for accuracy.. Doses for street meth or frequent use may be higher. Bioavailability >90% Threshold < 5 mg Light 5 - 10 mg Common 10 - 20 mg Strong 20 - 60 mg Heavy 60 mg + Duration Total 1 - 3 hours Onset 0 - 2 minutes Peak 20 minutes Offset 1 hour Afterglow 2 - 3 hours Oral Dosage WARNING: Always start with lower doses due to differences between individual body weight, tolerance, metabolism, and personal sensitivity. See responsible use section. DISCLAIMER: PW's dosage information is a summary of data gathered from users and resources. It is not a recommendation and should be verified with other sources for accuracy.. Doses for street meth or frequent use may be higher. Threshold 5 mg Light 5 - 15 mg Common 10 - 30 mg Strong 20 - 60 mg Heavy 40 - 150 mg + Duration Total 6 - 9 hours Onset 30 - 60 minutes Peak 3 - 5 hours Offset 3 - 4 hours Afterglow 2 - 5 hours

Summary sheet: Methamphetamine

Pure shards of methamphetamine hydrochloride, commonly known as "crystal meth".

Methamphetamine (N-methyl-alpha-methylphenethylamine) is a potent neurotoxic stimulant of the phenethylamine and amphetamine classes that is used as a recreational drug and, rarely, to treat attention deficit hyperactivity disorder (ADHD) and obesity.

Methamphetamine hydrochloride is approved by the United States Food and Drug Administration (USFDA) under the trade name Desoxyn. However, it is rarely prescribed due to the potential risks. Recreationally, methamphetamine is used to lift the mood, increase energy, and increase sexual desire, allowing some users to engage in sexual activity continuously for several days straight.

In low doses, methamphetamine can cause an elevated mood and increase alertness, concentration, and energy in fatigued individuals. At higher doses, it can induce psychosis, rhabdomyolysis and cerebral hemorrhage. Unlike amphetamine, methamphetamine is neurotoxic to humans, damaging both dopamine and serotonin neurons within the central nervous system. Unlike the long-term use of amphetamine, there is evidence that methamphetamine causes brain damage from long-term use in humans; this damage includes adverse changes in brain structure and function, such as reductions in gray matter volume in several brain regions and adverse changes in markers of metabolic integrity.

Chemistry

Methamphetamine, or N-methyl-1-phenylpropan-2-amine, is a synthetic molecule of the amphetamine family. Molecules of the amphetamine class contain a phenethylamine core featuring a phenyl ring bound to an amino (NH2) group through an ethyl chain with an additional methyl substitution at R_α. Amphetamines are alpha-methylated phenethylamines. Methamphetamine contains an additional methyl substitution at R_N, a substitution which is shared with MDMA and mephedrone. Methamphetamine exists as two enantiomers, dextrorotary and levorotary. Dextromethamphetamine is a stronger central nervous system (CNS) stimulant than levomethamphetamine; however, both are addictive and produce the same toxicity symptoms at high doses.

Pharmacology

Methamphetamine affects the central nervous system (CNS) by acting as a releasing agent for neurotransmitters such as dopamine, norepinephrine, and serotonin. It also acts as a reuptake inhibitor, increasing levels of monoamines by forcing the neurotransmitters out of their storage vesicles and expelling them into the synaptic gap by making the dopamine transporters work in reverse. Other mechanisms by which methamphetamine are known to increase monoamine levels are by:

• Blocking the reuptake of monoamines by inhibiting the activity of monoamine transporters
• Decreasing the expression of dopamine transporters at the cell surface
• Increasing cytosolic levels of monoamines by inhibiting the activity of monoamine oxidase (MAO)
• Increasing the activity and expression of the dopamine-synthesizing enzyme tyrosine hydroxylase (TH)

In addition to releasing potent amounts of monoamines, MA has a high lipid solubility which leads to a relatively fast transfer of the drug across the blood brain barrier and a quick onset in comparison to other stimulants. All of this results in feelings of reward, euphoria and stimulation and an unpleasant offset.

Subjective effects

The effects listed below are based upon the subjective effects index and personal experiences of PsychonautWiki contributors. The listed effects will rarely (if ever) occur all at once, but heavier dosages will increase the chances and are more likely to induce a full range of effects.

Physical effects

• Stimulation - In terms of its effects on the physical energy levels of the user, methamphetamine is usually considered to be extremely energetic and stimulating in a fashion that is identical to that of amphetamine, but stronger than that of modafinil, caffeine, and MDMA. It is similar yet distinct from the stimulation experienced on MDMA, encouraging physical activities such as dancing, socializing, running, or cleaning. The particular style of stimulation which amphetamine presents can be described as forced. This means that at higher dosages, it becomes difficult or impossible to keep still as jaw clenching, involuntarily bodily shakes and vibrations become present, resulting in extreme shaking of the entire body, unsteadiness of the hands, and a general lack of motor control.
• Increased heart rate
• Dehydration
• Appetite suppression
• Nausea
• Frequent urination
• Abnormal heartbeat
• Vasoconstriction
• Temporary erectile dysfunction
• Bronchodilation
• Increased perspiration
• Increased blood pressure
• Body odor alteration - Methamphetamine can potentially leave a very distinct and unpleasant odor within one's urine, sweat and general bodily secretions.

Cognitive effects

The cognitive effects of methamphetamine can be broken down into several components which progressively intensify proportional to dosage. The general head space of methamphetamine is described by many as one of extreme mental stimulation, increased focus, and powerful euphoria. It contains a large number of typical stimulant cognitive effects. Although negative side effects are usually mild at low to moderate dosages, they become increasingly likely to manifest themselves with higher amounts or extended usage. This particularly holds true during the offset of the experience.

The most prominent of these cognitive effects generally include:

• Focus enhancement - This component is most effective at low to moderate dosages as anything higher will usually impair concentration.
• Ego inflation
• Wakefulness
• Sexual arousal
• Thought acceleration
• Analysis enhancement
• Memory enhancement
• Motivation enhancement
• Euphoria
• Compulsive redosing

After effects

The effects which occur during the offset of a stimulant experience generally feel negative and uncomfortable in comparison to the effects which occurred during its peak. This is often referred to as a "comedown" and occurs because of neurotransmitter depletion. Its effects commonly include:

• Cognitive fatigue
• Thought deceleration
• Anxiety
• Depression
• Wakefulness
• Irritability

Toxicity and harm potential

Unlike amphetamine, methamphetamine is directly neurotoxic to dopamine neurons. Moreover, methamphetamine abuse is associated with an increased risk of Parkinson's disease due to excessive pre-synaptic dopamine autoxidation, a mechanism of neurotoxicity. Similar to the neurotoxic effects on the dopamine system, methamphetamine can also result in neurotoxicity to serotonin neurons. It has been demonstrated that a high core temperature is correlated with an increase in the neurotoxic effects of methamphetamine. As a result of methamphetamine-induced neurotoxicity to dopamine neurons, chronic use may also lead to post acute withdrawals which persist beyond the withdrawal period for months, and even up to a year.

Lethal dosage

A methamphetamine overdose may result in a wide range of symptoms. A moderate overdose of methamphetamine may induce symptoms such as: abnormal heart rhythm, confusion, dysuria, high or low blood pressure, hyperthermia, hyperreflexia, myalgia, severe agitation, tachypnea, tremor, urinary hesitancy, and urinary retention. An extremely large overdose may produce symptoms such as adrenergic storm, methamphetamine psychosis, anuria, cardiogenic shock, cerebral hemorrhage, circulatory collapse, hyperpyrexia, pulmonary hypertension, renal failure, rhabdomyolysis, serotonin syndrome, and a form of stereotypy ("tweaking"). A methamphetamine overdose will likely also result in mild brain damage due to dopaminergic and serotonergic neurotoxicity. Death from fatal methamphetamine poisoning is typically preceded by convulsions and coma.

It is strongly recommended that one use harm reduction practices when using this drug.

Tolerance and addiction potential

Tolerance is expected to develop with regular methamphetamine use and, when abused, this tolerance develops rapidly.

The evidence on effective treatments for amphetamine and methamphetamine dependence and abuse is limited. In light of this, fluoxetine and imipramine appear to have some limited benefits in treating abuse and addiction, "no treatment has been demonstrated to be effective for the treatment of methamphetamine dependence and abuse".

In highly dependent amphetamine and methamphetamine abusers, "when chronic heavy users abruptly discontinue [methamphetamine] use, many report a time-limited withdrawal syndrome that occurs within 24 hours of their last dose". Withdrawal symptoms in chronic, high-dose users are frequent, occurring in up to 87.6% of cases, and persist for three to four weeks with a marked "crash" phase occurring during the first week. Methamphetamine withdrawal symptoms can include anxiety, drug craving, dysphoric mood, fatigue, increased appetite, increased movement or decreased movement, lack of motivation, sleeplessness or sleepiness, and vivid or lucid dreams. Withdrawal symptoms are associated with the degree of dependence (i.e., the extent of abuse). The mental depression associated with methamphetamine withdrawal lasts longer and is more severe than that of cocaine withdrawal.

Psychosis

Main article: Stimulant psychosis

Abuse of methamphetamine can result in a stimulant psychosis that may present with a variety of symptoms (e.g., paranoia, hallucinations, delusions). A review on treatment for amphetamine, dextroamphetamine, and methamphetamine abuse-induced psychosis states that about 5–15% of users fail to recover completely. The same review asserts that, based upon at least one trial, antipsychotic medications effectively resolve the symptoms of acute amphetamine psychosis. Psychosis very rarely arises from therapeutic use.

Dangerous interactions

Although many drugs are safe on their own, they can become dangerous and even life-threatening when combined with other substances. The list below contains some common potentially dangerous combinations, but may not include all of them. Certain combinations may be safe in low doses of each but still increase the potential risk of death. Independent research should always be done to ensure that a combination of two or more substances is safe before consumption.

• Tricyclic antidepressants - Amphetamine may increase the effects of tricyclic antidepressants to dangerous levels.
• 25x-NBOMe - Both the NBOMe series and amphetamines induce powerful stimulation. Side effects such as thought loops, seizures, increased blood pressure, vasoconstriction, increased heart rate, and heart failure (in extreme cases) may occur.
• Alcohol - It is dangerous to combine alcohol, a depressant, with stimulants due to the risk of excessive intoxication. Stimulants decrease the sedative effect of alcohol which is the main factor most people consider when determining their level of intoxication. Once the stimulant wears off, the effects of alcohol will be significantly increased, leading to intensified disinhibition as well as other effects. If combined, one should strictly limit themselves to only drinking a certain amount of alcohol per hour.
• DXM - This combination may cause increased heart rate and panic attacks (in extreme cases).
• MXE - Increased heart rate and blood pressure may occur.
• Tramadol - This combination can increase the risk of seizures.
• MDMA - The neurotoxic effects of MDMA may be increased when combined with amphetamines.
• MAOIs - This combination may increase the amount of neurotransmitters such as dopamine to dangerous or even fatal levels. Examples include syrian rue, banisteriopsis caapi, 2C-T-2, 2C-T-7, αMT, and some antidepressants.
• Cocaine - This combination may increase strain on the heart.

Legal issues

The production, distribution, sale, and possession of methamphetamine is restricted or illegal in many jurisdictions. Methamphetamine has been placed in Schedule II of the United Nations Convention on Psychotropic Substances treaty.

See also

• Responsible use
• Stimulant
• Substituted amphetamine

External links

• Methamphetamine (Wikipedia)
• Methamphetamine (Erowid)