Phenazepam | The JHI

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Phenazepam

Found in:  

Fentanyl, BZD

Type/Reason added:  

DBZD

Relative Potency:  

N/A

Overview

The Effects

Treatment Options

Supportive Care:

Acute benzodiazepine intoxication primarily relies on supportive care for management. This may include definitive airway management via endotracheal intubation.

Antidote:

While the antidote flumazenil can effectively reverse benzodiazepine-mediated sedation, its use in acute benzodiazepine intoxication is not recommended due to the potential risks that may outweigh benefits as it can precipitate acute withdrawal syndromes, lower seizure threshold, and cause cardiac dysrhythmias.

Pharmacokinetics and Dynamics

Metabolism:

Phenazepam exhibits a marked difference in elimination half-life depending on the route of administration. Following intravenous injection, the half-life is approximately 15 hours. However, oral administration results in a significantly extended half-life, reaching around 103 hours. (7)

Drug-Drug Interactions:

Phenazepam has dangerous interactions with alcohol, opioids (e.g., heroin, fentanyl, oxycodone), other benzodiazepines, and barbiturates. Combining it with these substances greatly increases the risk of fatal respiratory depression, blackouts, and overdose. It also interacts with CYP3A4 inhibitors (such as grapefruit juice and some antibiotics), which can prolong its effects and increase toxicity.