A white powder easily dissolved in water, methamphetamine may be abused by ingestion, insufflation ("snorting"), parenteral injection, and smoking. "Ice" refers to a pure preparation of methamphetamine hydrochloride in large crystalline form.
Clinical effects of methamphetamine use are similar to those noted with cocaine use, manifesting as a sympathomimetic toxidrome. Although clinically indistinguishable from cocaine toxicity, the duration of effects is appreciably longer. Habituated users may use methamphetamine every few hours around the clock, for periods of 3 to 6 days, a use pattern typically referred to as a "run." The initial euphoric stimulant "rush" degenerates during the course of the run into a series of repetitive activities, often referred to as "tweaking." During the period of tweaking, paranoia and hallucinations may appear. After the run, a depressive phase referred to as a "crash" occurs.
The most common cardiovascular manifestations of toxicity are tachycardia and hypertension, although myocardial ischemia has been reported. Despite the cardiovascular effects, central nervous system (CNS) toxicity is the primary reason most methamphetamine users present for medical care. Patients are typically anxious and aggressive, and life-threatening agitation may occur. Visual and tactile hallucinations and psychoses are common. Poor dentition is common among chronic users ("meth mouth"), and appears multifactorial in nature.
3,4-Methylenedioxymethamphetamine (MDMA, "ecstasy") is a synthetic blend of methamphetamine and mescaline, resulting in promotion of serotonin release and inhibition of reuptake. In addition to signs and symptoms of methamphetamine toxicity, MDMA may result in syndrome of inappropriate antidiuretic hormone (SIADH) with subsequent hyponatremia and cerebral edema.
Emergency Department Treatment and Disposition
Treatment is primarily supportive, and is focused upon the signs and symptoms of toxicity. Cardiac monitoring is indicated for symptomatic patients. As with other causes of sympathomimetic toxicity, initial management focuses upon control of agitation and hyperthermia and prevention of complications (eg, rhabdomyolysis). Benzodiazepines are the first line of therapy for agitation. Hypertonic sodium may be indicated for MDMA-associated cerebral edema and seizures.
"Ice" Methamphetamine. An example of the "ice" form of amphetamines with a pipe. (Photo contributor: US Drug Enforcement Administration.)
Ecstasy. Examples of the candy-like appearance of ecstasy tablets. (Photo contributor: US Drug Enforcement Administration.)
Early "Meth Mouth." "Meth mouth," the extensive and accelerated dental caries associated with chronic methamphetamine abuse. (Photo contributor: R. Jason Thurman, MD.)
Advanced "Meth Mouth." Note the severe dental decay in this chronic methamphetamine abuser. (Photo contributor: Carson Harris, MD.)
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