[Use of activated charcoal in acute poisonings: clinical safety and factors associated with adverse reactions in 575 cases].

BACKGROUND AND OBJECTIVE: To identify the pattern of use of activated charcoal in the treatment of poisonings, and to evaluate the prevalence and severity of adverse reactions and define the risk factors associated with them. PATIENTS AND METHOD: Observational, prospective 7-year study. Patients receiving activated charcoal for gut decontamination were included. Epidemiological, toxicological, therapeutic and evolutionary variables were studied. The dependent variable was the appearance of secondary effects related to the use of charcoal. RESULTS: A total of 575 patients were included. The mean age was 37.8 (14.8) years and 65.7% were women. Activated charcoal was administered orally in 88% of the patients and by gastric tube after lavage in 12%, and 2.4% of patients received charcoal before hospital arrival. Adverse reactions occurred in 41 cases (7.1%) and included nausea or vomiting (36 patients), bronchoaspiration (6 patients) and pneumonia (2 patients). Spontaneous vomiting before administration of charcoal (p < 0.001), pre-hospital administration of charcoal (p < 0.05), repeated doses (p < 0.01) and the need for symptomatic measures to treat intoxicated patients (p < 0.05) were independent risk factors for adverse reactions, whereas age ≥ 40 years (p < 0.05) and intoxication with benzodiazepines (p < 0.01) were independently associated with a smaller risk of adverse reactions. The mean emergency department stay was 10.2 (18.6) hours, and was significantly longer (p < 0.05) in patients suffering adverse reactions. A total of 75.4% of patients were discharged to home, 20.5% required psychiatric admission and 3.9% were admitted due to the clinical consequences of the poisoning. The prevalence of non-psychiatric admission to general hospital or intensive care was greater in patients suffering adverse reactions. No patient died. CONCLUSIONS: Adverse reactions to charcoal are infrequent and rarely severe, but are associated with a greater emergency department stay and a trend to greater hospital admission. Predisposing factors are vomiting before administration of charcoal and administration of repeated doses. Age ≥ 40 years and ingestion of benzodiazepines are protective factors.