Approach to benzodiazepine and barbiturate use, intoxication, and overdose: Clinical sciences

Benzodiazepines and barbiturates are two common types of sedatives and anxiolytics typically used to treat panic disorder, anxiety disorders, and insomnia. Both classes bind to gamma-aminobutyric acid, or GABA, receptors and increase the affinity of the receptor to bind to GABA, a primary inhibitory neurotransmitter. This results in an inhibitory effect within the central nervous system by reducing neuronal excitability. This process produces symptoms of sedation by preventing overstimulation of the brain.

Both benzodiazepines and barbiturates have addictive properties, which can lead to chronic dependance, misuse and overuse. Of the two, benzodiazepines are more commonly used in clinical settings. Barbiturates, on the other hand, are no longer used as often due to their narrow therapeutic window and ease of overdose. Keep in mind that illicit use of these medications without a legitimate prescription is common.

Alright, when a patient presents with a chief concern suggestive of benzodiazepine or barbiturate use, first perform an ABCDE assessment to determine if they are stable or unstable.

Your goal here is to determine if the patient is actively experiencing an overdose which is a medical emergency. If the patient is unstable, stabilize their airway, breathing, and circulation right away. Provide supplemental oxygen and have a low threshold for endotracheal intubation. Make sure to assess for the Glasgow Coma Scale, or GCS. If the GCS score is less than 8, intubation is indicated.

Additionally, obtain IV access and consider starting IV fluids. Then, continuously monitor vital signs including temperature, heart rate, blood pressure, respiratory rate, oxygen saturation, and cardiac telemetry. Lastly, consider using cooling blankets if the patient is hyperthermic.

Next, perform a focused history and physical and order a urine and/or a serum toxicology screen. If the patient is unable to communicate, obtain history from a family member or a friend accompanying the patient. History will often reveal a recent or chronic use of benzodiazepine or barbiturate. For patients with recent use, try to determine how much of which drug was ingested and when. The amount and timing of ingestion is important when anticipating the acute clinical course of the patient. For example, if the patient ingested a large amount shortly before the presentation, you can expect the symptoms to get worse as the substances continues to be absorbed.

On exam, you might see altered mental status ranging from confusion to stupor to a coma.

If the patient is awake and alert, they might show signs of hallucinations, psychosis, or anterograde amnesia.

One important exam finding to look for is severe respiratory depression, defined as respiratory rate of 8 or below. This is an ominous sign for respiratory collapse which can quickly lead to death if not addressed. Additional findings you might see are ataxia, nystagmus, hypotonia, or hyporeflexia. With these findings, diagnose benzodiazepine or barbiturate overdose.

Although clinical findings are enough to make the diagnosis of overdose and start intervention, toxicology screening will help identify the causative agent. However, you should never wait for the tox screen results to start your treatment!

Now, the management of confirmed benzodiazepine or barbiturate overdose is mostly supportive. This includes providing supplemental oxygen or mechanical ventilation, IV fluids, and other symptom management. Flumazenil may be administered, but should be used with caution, as it can precipitate withdrawal symptoms and seizures. The goal is to support respiratory and circulatory function until the body clears out the substance.

Time for a high-yield fact! Flumazenil can be specifically used in benzodiazepine overdose as an antidote to reverse the effects, but it does not reverse the effects of a barbiturate overdose!

Now that we’ve taken care of the unstable patients, let’s talk about the stable ones. Your next step here is to obtain a focused history and physical exam and order a toxicology screen. If the patient has a history of recent benzodiazepine or barbiturate use, and presents with gait ataxia, slurred speech, mildly reduced heart rate and blood pressure, consider benzodiazepine or barbiturate intoxication.