Methamphetamine

Methamphetamine is a psychostimulant (having antidepressant or mood-elevating properties) drug used primarily for recreational purposes (under the street-name crystal meth), but is sometimes prescribed for Attention-deficit hyperactivity disorder and narcolepsy under the brand name Desoxyn. It causes euphoria and excitement by acting directly on the brain's reward mechanisms, thus making it highly addictive. Methamphetamine rapidly enters the brain and causes a cascading release of norepinephrine (stress hormone that activates fight or flight response in emergencies) and dopamine (providing feelings of enjoyment and reinforcement to motivate a person proactively to perform certain activities). Users may become obsessed or perform repetitive tasks such as cleaning, hand-washing or assembling and disassembling objects. Withdrawal is characterized by increased sleeping and eating, and depression-like symptoms, often accompanied by anxiety and drug-craving.

In the U.S., illicit methamphetamine comes in a variety of forms, with an average price of $150 per gram of pure substance. Most commonly it is found as a colorless crystalline solid, sold on the street under the name crystal meth and a variety of other names. It is also sold as a less pure crystalline powder called crank, or in crystalline rock form. Methamphetamine found on the street is rarely pure, but adulterated with chemicals that were used to synthesize it. It may be diluted or "cut" with non-psychoactive substances like inositol. It may also be cut with other psychoactive substances, but the reverse is presumably more common due to its low price relative to other common drugs.

Methamphetamine is a potent central nervous system stimulant which affects neurochemical mechanisms responsible for regulating heart rate, body temperature, blood pressure, appetite, attention, mood and responses associated with alertness or alarm conditions. Methamphetamine causes the norepinephrine and dopamine transporters to reverse their direction of flow. This inversion leads to a release of these transmitters from the vesicles to the cytoplasm and from the cytoplasm to the synapse, causing increased stimulation of post-synaptic receptors. Methamphetamine also indirectly prevents the reuptake of these neurotransmitters, causing them to remain in the synaptic cleft for a prolonged period.

The acute effects of the drug closely resemble the physiological and psychological effects of an epinephrine-provoked fight-or-flight response, including increased heart rate and blood pressure, vasoconstriction (constriction of the arterial walls), bronchodilation, and hyperglycemia (increased blood sugar). Users experience an increase in focus, increased mental alertness, and the elimination of fatigue, as well as a decrease in appetite.

Tolerance
As with other amphetamines, tolerance to methamphetamine is not completely understood, but known to be sufficiently complex that it cannot be explained by any single mechanism. The extent of tolerance and the rate at which it develops varies widely between individuals, and even within one individual it is highly dependent on dosage, duration of use and frequency of administration. Prolonged overstimulation of dopamine receptors caused by methamphetamine may eventually cause the receptors to downregulate in order to compensate for increased levels of dopamine within the synaptic cleft. To compensate, larger quantities of the drug are needed in order to achieve the same level of effects.

Side effects

Meth Mouth
Methamphetamine addicts may lose their teeth abnormally quickly, a condition known as "meth mouth". This effect is not caused by the commonly-repeated myth that meth itself has "corrosive" effects on teeth. 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 tooth grinding and clenching." Similar, though far less severe symptoms have been reported in clinical use of other amphetamines, where effects are not exacerbated by a lack of oral hygiene for extended periods. Like other substances which stimulate the sympathetic nervous system, methamphetamine causes decreased production of acid-fighting saliva and increased thirst, resulting in increased risk for tooth decay, especially when thirst is quenched by high-sugar drinks.

Immediate and Chronic Effects

• Diarrhea, nausea

• Loss of appetite, insomnia, tremor, jaw-clenching (Bruxism)

• Agitation, compulsive fascination with repetitive tasks (Punding)

• Talkativeness, irritability, panic attacks

• Increased libido

• Dilated pupils

Side effects associated with chronic use:

• Drug craving

• Weight loss

• Withdrawal-related depression and anhedonia

• Rapid tooth decay ("meth mouth")

• Amphetamine psychosis

• Acne and skin sores

Side effects associated with overdose:

• Formication (sensation of flesh crawling with bugs, with possible associated compulsive picking and infecting sores)

• Brain damage (Neurotoxicity)

• Paranoia, delusions, hallucinations

• Kidney damage (from Hyperkalemia)

Overdose fatalities are usually due to stroke or heart failure, but can also be caused by hyperthermia or kidney failure.

Addiction
Methamphetamine is highly addictive, particularly when injected or smoked. While not life-threatening, withdrawal is often intense and, as with all addictions, relapse is common. In an article about his son's addiction to methamphetamine, a California writer who has also experimented with the drug put it this way:This drug has a unique, horrific quality. In an interview, Stephan Jenkins, a singer in the band Third Eye Blind, said that methamphetamine makes you feel 'bright and shiny.' It also makes you paranoid, incoherent and both destructive and pathetically and relentlessly self-destructive. Then you will do unconscionable things in order to feel bright and shiny again.

Former users have noted that they feel stupid or dull when they quit using methamphetamine. This is because the brain is adapting a need for methamphetamine to think faster, or at what seems to be a higher level. Individuals with ADHD may be at higher risk for addiction to methamphetamine, because the drug increases the user's ability to focus and reduces impulsivity. Because of its abuse potential, meth is not generally prescribed for ADHD unless other stimulants, such as methylphenidate (Ritalin®), dextroamphetamine (Dexedrine®) or mixed amphetamines (Adderall®) have failed. With long-term use, abstinence often leads to slow thinking and depression, which in turn requires that the addict use more meth to 'fix' it. A chronic pattern of such behavior is known colloquially as "The Vampire Life."

Serious drug addiction correlates with poor hygiene and general self-care, and even minor health problems can lead to serious complications when left untreated. Striking health problems popularly associated with methamphetamine addiction, such as severe tooth decay or massive skin infections, are caused by unsterilized needles and a lack of hygiene. Even long-term use does not generally result in outward symptoms, but may lead to hypertension, damage to heart valves, and increased risk of strokes.

Routes of administration
The usual route for medical use is oral administration. In recreational use it can be swallowed, snorted, smoked, dissolved in water and injected (or even without water, in what is called a dry shot). As with all addictive drugs, the potential for addiction is greater when it is delivered by methods that cause the concentration in the blood to rise quickly, principally because the effects desired by the user are felt more quickly and with a higher intensity than through a moderated delivery mechanism. In fact, studies have shown that the subjective pleasure of drug use (the reinforcing component of addiction) is proportional to the rate that the blood level of the drug increases. In general, smoking is the fastest mechanism (i.e., it causes the blood concentration to rise the most quickly in the shortest period of time as it allows the substance to travel to the brain through a more direct route than intravenous injection), followed by injecting, snorting, anal insertion, and swallowing.

"Smoking" methamphetamine actually refers to vaporizing it to produce fumes, rather than burning and inhaling the resulting smoke, as with tobacco. It is commonly smoked in glass pipes, or in aluminum foil heated by a flame underneath. This method is also known as "chasing the white dragon" (as derived from the method of smoking heroin known as "chasing the dragon"). There is little evidence that methamphetamine inhalation results in greater toxicity than any other route of administration. Lung damage has been reported with long-term use, but manifests in forms independent of route (pulmonary hypertension and associated complications), or limited to injection users (pulmonary emboli).

Injection is a popular method for use, but potentially carries quite serious risks. The hydrochloride salt of methamphetamine is soluble in water; injection users may use any dose from 125 mg to over a gram in one I.V. dose using a small needle. This dosage range may be fatal to non-addicts; addicts rapidly develop tolerance to the drug. Injection users often experience skin rashes (sometimes called "speed bumps") and infections at the site of injection. As with any injected drug, if a group of users shares a common needle or any type of injecting equipment without sterilization procedures, blood-borne diseases such as HIV or hepatitis can be transmitted as well.