Benzodiazepine overdose

Overview 
Theory 
Diagnosis 
Management 
Follow up 
Resources 

Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups: see disclaimer

ACUTE

all patients

1st line – ABCDE assessment and supportive care

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1st line –

ABCDE assessment and supportive care

Resuscitation and supportive treatment will be needed.

Perform an Airway, Breathing, Circulation, Disability, Exposure (ABCDE) assessment and re-assess the patient regularly throughout treatment.[30]

Be alert to the possibility of respiratory arrest. It can occur in the case of a large overdose or when there is co-ingestion of other respiratory depressants (e.g., opioid, alcohol). Assisted ventilation may be necessary.[31]

Ensure adequate fluid resuscitation if the patient is hypotensive.[24]

Refer early to critical care if the patient has fluid-resistant hypotension as this can result in very rapid deterioration.
Invasive vascular monitoring and echocardiography may help determine the choice between inotropes or vasopressors because reduced cardiac output and vasodilation may both be present in severe or mixed poisoning.

See Shock and Acute respiratory failure for more information.

Clinical treatment of overdose is by symptom management. Maintain the patient’s airway and respiration, and provide haemodynamic support while excluding other diagnoses. Consult your approved clinical toxicology resource (e.g., TOXBASE in the UK) and/or seek advice from your national or regional poisons information service. National Poisons Information Service: TOXBASE Opens in new window

Seek urgent advice from the vascular surgery team if benzodiazepines have been injected intra-arterially.[24]

Most patients with pure benzodiazepine overdose present with mild central nervous system (CNS) depression, particularly sedation with no respiratory depression. Once the diagnosis has been confirmed, they usually require only observation until metabolism of the benzodiazepine leads to a natural recovery.[25]

Check and monitor:[24]

Cardiac rhythm
Vital signs
Capillary blood glucose
Pupil size.

Observe the patient for a minimum of 4 hours after exposure.[24]

After 4 hours, asymptomatic patients can be discharged. Advise the patient to return if symptoms develop.[24]

Consider any indications that lead you to suspect that poisoning was intentional as an act of self-harm:[18]

Take urgent steps to establish the patient’s emotional and mental state at the same time as assessing physical risk.
Request a psychosocial assessment by a trained member of staff. Do not delay this until after medical treatment unless life-saving treatment is needed.
Offer a safe, supportive environment for the patient to wait for treatment, with regular supervision and contact from a named staff member to ensure safety.
See Suicide risk mitigation.

Consider – flumazenil (with caution)

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Consider –

flumazenil (with caution)

Additional treatment recommended for SOME patients in selected patient group

Flumazenil is not licensed in the UK for the treatment of acute benzodiazepine poisoning, although it is licensed for this indication in some other countries.[28] The risks of flumazenil often outweigh the benefits and its use is inappropriate for most patients presenting to the emergency department with benzodiazepine toxicity. Always seek expert advice if you believe the patient could benefit from flumazenil.[32]

Flumazenil must only be administered by, or under the supervision of, a clinician who has been explicitly trained in its use.[34] Full resuscitation equipment must be immediately available.

Flumazenil use has been associated with convulsions, particularly in patients who have co-ingested drugs associated with seizures. For this reason, it should not be used as a diagnostic test.

Flumazenil is a benzodiazepine antagonist which reverses the effects of benzodiazepines by competitive inhibition at the GABA/benzodiazepine-receptor complex.

Flumazenil may be used, with caution, by a specialist clinician to reverse impairment of airway or ventilation in patients poisoned with a benzodiazepine who meet strict clinical criteria. Its use should only ever be considered in a patient known to have pure benzodiazepine poisoning, who would otherwise require mechanical ventilation due to insufficient ventilation or coma.[24]

The purpose is to avoid intubation, artificial ventilation, and admission to intensive care.[18]
The specialist clinician must always use the minimum effective dose and administer only for as long as is necessary.
- The dose is likely to be lower than that used for other indications.[18]
Adequate ventilation is the objective. It is not necessary to fully reverse CNS depression.[24]

Patients require close observation. Flumazenil has a shorter half-life than most benzodiazepines and so rapid re-sedation can occur after apparent recovery.

Flumazenil should not be used:

As a ‘trial’ or diagnostic tool.[24]
In benzodiazepine-dependent patients.[32]
In any patient who has ingested a pro-convulsant, including a tricyclic antidepressant.[24]
In any patient who has features of sodium-channel antagonist or stimulant poisoning (wide QRS interval, tachycardia with large pupils), even if no such agent has been disclosed.[24]

Practical tip

In practice, there is a high likelihood that a patient presenting to the emergency department with a benzodiazepine overdose will have known or possible contraindications that will rule out use of flumazenil. The circumstances in which use of flumazenil might be considered will often make it difficult or impossible to get a reliable history from the patient, meaning that a mixed overdose or other contraindication cannot be excluded with certainty.

Primary options

flumazenil: consult specialist for guidance on dose

Consider – activated charcoal

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Benzodiazepine overdose

all patients

ABCDE assessment and supportive care

flumazenil (with caution)

Practical tip

Primary options

These drug options and doses relate to a patient with no comorbidities.

Primary options

Drug choice, dose and interactions may be affected by the patient's comorbidities. Check your local drug formulary.

Primary options

activated charcoal

Primary options

These drug options and doses relate to a patient with no comorbidities.

Primary options

Drug choice, dose and interactions may be affected by the patient's comorbidities. Check your local drug formulary.

Primary options

Benzodiazepine overdose

Treatment algorithm

all patients

ABCDE assessment and supportive care

flumazenil (with caution)

Practical tip

Primary options

These drug options and doses relate to a patient with no comorbidities.

Primary options

Drug choice, dose and interactions may be affected by the patient's comorbidities. Check your local drug formulary.

Primary options

activated charcoal

Primary options

These drug options and doses relate to a patient with no comorbidities.

Primary options

Drug choice, dose and interactions may be affected by the patient's comorbidities. Check your local drug formulary.

Primary options