Oxycodone injection requires more preparation. After the wax coating is removed, the pill is crushed into a fine powder, mixed with water, and liquefied over heat; any remaining wax is extracted, and the liquid is filtered through cotton and injected. Residual impurities can cause significant intravascular complications.
Stimulants
These agents include amphetamines and amphetamine-like drugs, such as phendimetrazine and benzphetamine, which are marketed as weight-loss medications. Methamphetamine is the most commonly abused drug in this class, with a lifetime use rate, throughout the US population, of 4.9%.7 However, only a small proportion is derived from the prescription forms used to treat attention-deficit/hyperactivity disorder or narcolepsy.
The two most commonly abused individual stimulants are methylphenidate (Ritalin®) and dextroamphetamine (Dexedrine®), with US lifetime use rates of 1.7% and 1.1%, respectively.7 As a class, prescription diet pills have a higher rate of nonmedical US lifetime use, 3.4%.
Despite amphetamines' low therapeutic index, persons who use them are known to develop high tolerance with ongoing use.18 Clinical response to amphetamines can be described as sympathomimetic effects, with CNS signs and symptoms ranging from anxiety and euphoria to severe agitation, hyperthermia, and seizures. Tachycardia, hypertension, diaphoresis, and tremors are classic symptoms. Potentially lethal complications include tachyarrhythmias, myocardial infarction, rhabdomyolysis, status epilepticus, and intracranial hemorrhage. Chronic use can lead to cardiomyopathy, dental decay, paranoia, and pulmonary hypertension.
The mainstays of treatment include blunting the sympathomimetic response with benzodiazepines and addressing the secondary complications of stimulant use. Managing agitation, hyperthermia, rhabdomyolysis, seizures, and tachydysrhythmias are critical following severe toxicity.18
Sedative-Hypnotic Medications
Under the umbrella of sedative-hypnotic agents fall benzodiazepines, barbiturates, skeletal muscle relaxants, antidepressants, and antihistamines. Certainly, benzodiazepines dominate this assortment, but several other medications pose serious risk when used nonmedically. Despite their preponderance, benzodiazepines cause relatively few deaths (compared with barbiturates), especially when they are used alone.
Although the clinical presentation of a patient with benzodiazepine overdose varies according to the specific agent ingested, common features include drowsiness, CNS depression, stupor, nystagmus, hypothermia, respiratory depression, and coma.18 Occasionally, ataxia is the only presenting sign of accidental benzodiazepine ingestion in the pediatric patient, but CNS depression is usually present. Cardiovascular instability can result directly, from depression of myocardial contractility, medullary depression, and vasodilation; or indirectly, from respiratory compromise. Ancillary signs, such as barbiturate blisters, may facilitate the diagnosis.
Primary treatment remains airway support with symptomatic and supportive care. Though rarely indicated following benzodiazepine poisoning, flumazenil is a competitive inhibitor of benzodiazepine receptors. It should be considered only in patients previously naive to benzodiazepines (as in the case of accidental pediatric ingestion) or following iatrogenic sedation. Use of flumazenil after long-term benzodiazepine therapy or in patients with a lowered seizure threshold may precipitate an acute withdrawal state, arrhythmias, and seizures. With proper airway support and monitoring, most patients improve clinically as the drugs are metabolized.18
Preventive Strategies for Emergency Medicine Clinicians
Although data involving emergency PAs and NPs are not readily available, fewer than 40% of physicians receive formal medical school training in recognizing prescription drug abuse or diversion.4 According to the Center on Addiction and Substance Abuse (CASA) survey, 43% of physicians neglect to ask about prescription drug abuse during the patient history.20
Because continuity of care is inherently lacking in emergency medicine, certain active interventions are recommended during the patient encounter to limit nonmedical use of prescription drugs. Three particularly important techniques are recognizing cardinal features of patients who seek to obtain psychotherapeutic medications for nonmedical purposes; adapting prescription writing habits to provide safe, appropriate interventions; and educating patients.
In a limited time, EMPs must obtain as much information as possible about a patient's illness and personal situation without appearing to be suspicious or judgmental; confrontations may prompt some patients to resort to verbal aggression. Many EMPs pride themselves on their aptitude for "reading" patients and gaining their trust during the initial encounter.
Patterns in the medical records may indicate a history of prescription drug abuse. A more detailed history might elicit other relevant risk factors: a history of chronic pain, psychiatric disorders—even smoking within one hour of waking in the morning.4,20 In the presence of two or more risk factors, strong consideration should be given to nonnarcotic treatment of pain and referral to a primary care clinician for multidisciplinary intervention.
Several available screening tools can increase sensitivity while standardizing the process; examples are the Screener and Opioid Assessment for Patients in Pain (see www.painedu.org) and the Screening Instrument for Substance Abuse Potential.21 These may be more useful in the primary care or outpatient setting than in the ED with its time constraints.