Management of Benzodiazepine Overdose

Abstract

Today, benzodiazepines are the drugs most commonly involved in cases of self-poisoning. Fortunately, compared with several other drugs they are relatively safe in overdose, and symptoms of severe poisoning are rarely observed in young adults with pure benzodiazepine overdosage. However, respiratory depression, hypotension and prolonged coma are often seen in other patient groups with benzodiazepine overdosage, such as the elderly, children and patients with chronic pulmonary disease. Flumazenil, a specific benzodiazepine antagonist, is a valuable and safe diagnostic and therapeutic tool in the short term management of drug poisoning with involvement of benzodiazepines. Its use should therefore be considered in all unconscious patients admitted because of benzodiazepine overdosage. In self-poisoning, the drugs ingested are frequently a mixture of several compounds and their identity is often unknown. Flumazenil can also be used diagnostically in cases of unclear multiple drug poisoning or coma of unknown aetiology. During use of flumazenil, consideration should be paid to a few contraindications, including patients with epilepsy who are receiving long term benzodiazepine medication. Moreover, some precautions should be taken during administration, such as individual titration of the dosage to minimise the risk of inducing benzodiazepine withdrawal syndrome or unmasking toxic effects of other concurrently ingested drugs. A normal electrocardiogram recording before the antidote is given will imply a minimal risk of any adverse reactions in cases of combined intake of benzodiazepine and antidepressants. Further, the short half-life of flumazenil necessitates a period of careful supervision after its administration. Supportive care in a patient with benzodiazepine overdose includes close monitoring, preferably in the drainage position. If hypotension or prolonged eNS depression occurs, intravenous fluids should be administered. Occasionally, gastric lavage and administration of activated charcoal is indicated, but only if the patient is awake and potentially sensitive to benzodiazepines and if a large dose has been ingested within the last 1 to 2 hours.