Overview
Methamphetamine (also known as speed, meth,
crystal, crank, tina, and sometimes confusingly called ice) is a
chemical widely known for its stimulant properties on the human
body. It is frequently confused with other drugs that share
similar effects, including amphetamine, 4-methyl-aminorex,
ephedrine, caffeine, and other chemicals, both legal and
illegal.
Terminology
In this document, we shall refer to the
drugs by their common chemical names, rather than by "street
names", since the street names do not have a one-to-one
correspondence to actual chemicals. For example, the term
"speed" can mean methamphetamine or amphetamine. The term "ice"
is generally considered to apply to 4-methyl-aminorex, but is
often used to refer to relatively pure (and in some cases, not
so pure) forms of methamphetamine.
We shall use the term "methamphetamine" to refer to the substance
in either its free base (i.e. simple, unadorned) or salt
(usually hydrochloride) form. When precision is needed, we shall
explicitly state one form or the other.
Pharmacology
This is one of the most difficult sections
to write, partially because there is very little "science"
involved. The literature gives conflicting reports, due to the
fact that many criteria are subjective, and probably also due to
confusion over terminology.
The pharmacological effects of methamphetamine are very similar to
those of similarly structured molecules.
Administration
Methamphetamine can be taken orally,
snorted, smoked or injected, in approximately increasing order
of immediacy of onset.
Effects
These include euphoria, hyperexcitability,
extreme nervousness, accelerated heartbeat, sweating, dizziness,
restlessness, insomnia, tooth grinding, incessant talking, and
other effects.
Methamphetamine and other CNS stimulants have strong
bronchodilation effects. Vasoconstriction (tightening of blood
vessels) and pupil dilation are also common. Elevated blood
pressure, heart rate, and other general symptoms of increased
sympathetic nervous activity.
The physical effects are almost assuredly due to interactions
between the amphetamine structure and human physiology, probably
due to the similarity to adrenaline (epinephrine).
Mental capacity is not diminished directly by the drug. In fact,
some studies have shown slight increases in mental capacity on
simple tasks. It has been prescribed for attention deficit
disorder, among other things.
Confusing reports here tend to center around the effects of
fatigue on mental capacity.
Emotional responses may range from euphoria to anger and paranoia.
Preliminary doses tend to produce the former, while continued
use (e.g. for three or more days) tends to produce the latter.
It appears that these feelings may be linked to the
neurotransmitters dopamine and/or serotonin, although we have
not seen a good reference on this yet.
