special subjects
Sedatives
Treatment of Sedative Toxicity
Supportive care Rarelyflumazenilfor benzodiazepines Sometimes urine alkalinization and/or activatedcharcoalfor barbiturates Acute intoxication generally requires nothing more than supportive care, including monitoring the airway, respirations, and cardiovascular status. If ingestion was within 1 hour, the gag reflex is preserved, and the patient can protect the airway, 50 g of activatedcharcoalmay be given to reduce further absorption; however, this intervention has not been shown to reduce morbidity or mortality and is no longer routinely recommended. However, multidose activatedcharcoalis suggested to enhance elimination because of enterohepatic circulation ofphenobarbital, although studies supporting positive clinical outcome is lacking. Occasionally, intubation and mechanical ventilation are required. The benzodiazepine receptor antagonistflumazenilcan reverse sedation and respiratory depression secondary to benzodiazepine overdose. Dose is 0.2 mg IV given over 30 seconds; 0.3 mg may be given after 30 seconds, followed by 0.5 mg every 1 minute to total 3 mg. However, its clinical usefulness is not well-defined because most people who overdose on benzodiazepines recover with only supportive care, and occasionallyflumazenilprecipitates seizures. Contraindications toflumazenilinclude long-term benzodiazepine use (becauseflumazenilmay precipitate withdrawal), an underlying seizure disorder, presence of twitching or other motor abnormalities, a concomitant epileptogenic drug overdose (especially of tricyclic antidepressants), and cardiac arrhythmias. Because many of these contraindications are usually unknown in overdoses,flumazenilis best reserved for patients with respiratory depression during a medical procedure (ie, when medical history is clearly known). overdose by Hemodialysis ( Urinary alkalinizationis accomplished by adding 150 mEq (150 mmol)sodium bicarbonatediluted in 1 liter D5W and infused at a rate of 1 to 1.5 liters per hour. Urinary pH should be maintained as close to 8 as possible for effective alkalinization. Severe acute withdrawal of sedatives requires hospitalization for close monitoring of withdrawal symptoms, preferably in an intensive care unit, and use of appropriate doses of IV benzodiazepines. Oral benzodiazepines may be used if withdrawal symptoms are mild. One approach for managing sedative dependence is to withdraw the drug on a strict schedule while monitoring signs of withdrawal. Often, switching to a long-acting drug, which is easier to taper, is better. The timing of dose reduction depends on the presence and severity of withdrawal symptoms. 1.Hoyland K, Hoy M, Austin R, et al: Successful use of haemodialysis to treatphenobarbitaloverdose.BMJ Case Rep2013: bcr2013010011, 2013. doi: 10.1136/bcr-2013-010011 