Absorption of THC is rapid after inhalation and peak concentrations of cannabinoids and psychoactive symptoms occurs within minutes. After ingestion, however absorption can be unpredictable because cannabinoids are unstable at gastric pH and also undergo first-pass metabolism (CYP 2C9, 3A4). Onset of symptoms can vary between 1-3 hours, and concentrations can peak between 2-4 hours.
The clinical effects of pediatric exposure to marijuana vary depending on the amount ingested and size of the child. Most reported pediatric exposures are from ingestion.[7,11] Edible products pose a significant risk as they contain high amounts of THC and are attractive and palatable to children. . Passive smoke inhalation can produce symptoms in adults, but has not been studied or reported in children. There is evidence of passive smoke exposure leading to detectable cannabinoids in the urine in children.
Mild exposures can results in mild sleepiness, excessive happiness and laughter, and ataxia. Significant exposures can lead to increased muscle tone (or hyperkinetic activity), obtundation/coma, and apnea/bradypnea. Higher potency products can lead to anxiety, psychosis, and agitation in adolescence.
The clinical effects in pediatric population tend to last longer than adults, with some cases lasting 24-36 hours.