A teenager was brought into the emergency room following a lorazepam overdose. What antidote would the nurse expect to administer?
A.
Naloxone
B.
Acetylcysteine
C.
Physostigmine
D.
Flumazenil
The Correct answer and Explanation is:
The correct answer is D. Flumazenil.
Flumazenil is the antidote used to reverse the effects of benzodiazepine overdose, such as lorazepam. Lorazepam, a benzodiazepine, acts on the central nervous system by enhancing the effects of gamma-aminobutyric acid (GABA), a neurotransmitter that inhibits neuronal activity. This results in sedation, muscle relaxation, and anxiolytic effects, which can be life-threatening in an overdose situation due to excessive CNS depression, leading to respiratory failure and altered consciousness.
Mechanism of Action of Flumazenil: Flumazenil works by competitively inhibiting the action of benzodiazepines at the GABA receptor site in the brain. By binding to the same receptor as benzodiazepines, flumazenil prevents lorazepam from exerting its effects, thereby reversing sedation, drowsiness, and other symptoms associated with overdose.
Administration and Considerations: Flumazenil is typically administered intravenously in a hospital setting. The nurse should monitor the patient closely after administration because flumazenil has a shorter half-life than many benzodiazepines. This could result in the re-emergence of symptoms as the effects of flumazenil wear off. Repeated doses may be necessary depending on the severity of the overdose and the specific benzodiazepine involved.
Important Precautions: One critical consideration is that flumazenil can precipitate withdrawal and seizures, especially in patients with long-term benzodiazepine use or those who have overdosed on multiple substances, including tricyclic antidepressants. Therefore, careful patient assessment and monitoring are essential when administering this antidote.
Incorrect Options:
- A. Naloxone is the antidote for opioid overdoses, not benzodiazepines.
- B. Acetylcysteine is used to treat acetaminophen overdose.
- C. Physostigmine is used as an antidote for anticholinergic toxicity.
In summary, flumazenil is the appropriate antidote for a lorazepam overdose, making it the expected treatment in this emergency scenario.