Amphetamines are sympathomimetic drugs with central nervous system stimulant and euphoriant properties whose toxic adverse effects include delirium, hypertension, seizures, and hyperthermia (which can cause rhabdomyolysis and renal failure). Toxicity is managed with supportive care, including IV benzodiazepines (for agitation, hypertension, and seizures) and cooling techniques (for hyperthermia). There is no stereotypical withdrawal syndrome.
methylenedioxymethamphetamine (Ecstasy, MDMA), methylenedioxyethylamphetamine (MDEA), and numerous others.
Pathophysiology
Effects of amphetamines are similar, varying in intensity and duration of psychoactive effects; MDMA and its relatives have more mood-enhancing properties, perhaps related to a greater effect on serotonin. Amphetamines can be taken orally as pills or capsules, nasally by inhaling or smoking, or by injection.
Chronic effects
Repeated use of amphetamines induces dependence. Tolerance develops slowly, but amounts several 100-fold greater than the amount originally used may eventually be ingested or injected. Tolerance to various effects develops unequally. Tachycardia and increased alertness diminish, but hallucinations and delusions may occur.
Amphetamines typically cause erectile dysfunction in men but enhance sexual desire. Use is associated with unsafe sex practices, and users are at increased risk of sexually transmitted infections, including HIV infection
Necrotizing vasculitis that involves multiple organ systems can occur.
Phentermine
Acute effects
Many psychologic effects of amphetamines are similar to those of ; they include increased alertness and concentration, euphoria, and feelings of well-being and grandiosity. Palpitations, tremor, diaphoresis, and mydriasis may also occur during intoxication.
Binges (perhaps over several days) lead to an exhaustion syndrome, involving intense fatigue and need for sleep after the stimulation phase.
Toxicity or overdose
Tachycardia, arrhythmias, chest pain, hypertension, dizziness, nausea, vomiting, and diarrhea can occur. Central nervous system effects include acute delirium and toxic psychosis. Overdose can also cause stroke (usually hemorrhagic), seizures, muscle rigidity, and hyperthermia (> 40° C); all of these effects may precipitate rhabdomyolysis, which can lead to renal failure.
Chronic effects
A paranoid psychosis may result from long-term use of amphetamines; rarely, the psychosis is precipitated by a single high dose or by repeated moderate doses. Typical features include delusions of persecution, ideas of reference (notions that everyday occurrences have special meaning or significance personally meant for or directed to the patient), and feelings of omnipotence. Some users experience a prolonged depression, during which suicide is possible.
Users have a high rate of severe tooth decay affecting multiple teeth; causes include decreased salivation, acidic combustion products, bruxism, and poor oral hygiene.
Withdrawal
Usually a clinical diagnosis
Testing as needed to exclude serious nondrug-related disorders (eg, causing altered mental status)
Amphetamines are usually part of routine urine drug screens
IV benzodiazepines
IV nitrates for hypertension unresponsive to benzodiazepines as needed
Cooling for hyperthermia as needed
Toxicity or overdose
When a significant amount of amphetamines has recently been taken orally (eg, <
Hyperthermia can be life threatening and should be managed aggressively with sedation plus evaporative cooling, ice packs, and maintenance of intravascular volume and urine flow with IV normal saline solution.
Phenothiazines lower seizure threshold, and their anticholinergic effects can interfere with cooling; thus, they are not preferred for sedation.
Withdrawal and rehabilitation
No specific treatment is needed when patients stop taking of amphetamines. Blood pressure and mood should be monitored initially. Patients whose depression persists for more than a brief period after amphetamines are stopped may respond to antidepressants.
Cognitive-behavioral therapy (a form of psychotherapy) is effective in some patients. There are no proven pharmacologic treatments for rehabilitation and maintenance after detoxification.
More Information
The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.
Findtreatment.gov: Listing of licensed US providers of treatment for substance use disorders.
