- The classical triad of central nervous system depression, respiratory depression, and pinpoint pupils characterizes opioid toxicity.
- Some opioids, such as methadone and diphenoxylate-atropine (Lomotil), can have delayed or prolonged effects.
- Certain opioids can cause acute lung injury or noncardiogenic pulmonary edema in severe overdoses.
- Toxicity from proxyphene, meperidine, and tramadol, as well as neonatal opioid withdrawal, can result in seizure activity.
- Airway management and the use of the pure opioid antagonist naloxone are the mainstays of opioid toxicity treatment.
- Longer-acting opioid antagonists, such as nalmefene, may be effective in nonopioid-dependent children.
Opioids are naturally occurring or synthetic drugs that have activity similar to that of opium or morphine. The term opiate refers only to those drugs derived from natural opium, which includes morphine, codeine, and thebaine. The term narcotic is derived from the Greek word for stupor, and was originally used to describe any drug that could induce sleep, but became erroneously associated with opioids alone. Some have defined narcotics as those substances that bind opiate receptors, while others refer to any illicit substances as narcotics. The poppy plant Papaver somniferum is the source of all opium alkaloids.1
Opioids are used clinically for analgesia, anesthesia, as cough suppressants, and to alleviate diarrhea. These drugs are widely available for medical and illicit use in oral, inhalational, parenteral, transdermal, and suppository forms.
Neonates can experience lethargy at birth if there was recent maternal opioid use, or if large doses of an opioid agent were iatrogenically administered to the mother during labor. Additionally, the neonate is prone withdrawal symptoms during the newborn period if the mother exhibited chronic dependency during her later prenatal stages. Toddlers are prone to opioid poisoning if their environment permits exposure, most often from unintentional ingestions. For example, powdered heroin, methadone2 and codeine tablets, long-acting morphine derivatives, and fentanyl patches3 may be readily available to the younger child. Methadone is one of the more potentially toxic opioids to toddlers; the incidence of accidental ingestion is on the rise, resulting in serious poisonings with small doses.4,5 Chronically exposed newborn, withdrawal symptoms are rarely encountered in younger children unless the child is using opioids for chronic pain management.
A survey by the National Institute on Drug Abuse (NIDA) documented an 80% increase in opioid use among high school students over the past decade, heralding a resurgent heroin epidemic in the adolescent population.6 Adolescents tend to experiment with different routes of exposure, such as inhalational (smoking),7 intranasal (snorting), ingestion, or intravenous administration.8 In a suicide attempt, they are potentially exposed to life-threatening doses. In addition, opioids may have synergistic effects with other drug combinations such as ethanol, benzodiazepines, and GHB (γ-hydroxybutyrate), or opposing effects when mixed with sympathomimetic agents like cocaine and amphetamines. Chronically addicted teenagers are also prone to acute withdrawal states, particularly when treated with naloxone.1
Opium is broken down into alkaloid ...