What are the effects of a Clonazepam (Klonopin) overdose?

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Last updated: March 14, 2025View editorial policy

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From the Guidelines

If you suspect a Klonopin (clonazepam) overdose, seek emergency medical help immediately by calling 911 or your local emergency number. Symptoms of overdose include extreme drowsiness, confusion, impaired coordination, slowed or difficult breathing, unresponsiveness, and bluish lips or skin. Do not try to make the person vomit. While waiting for help, keep the person awake if possible, lay them on their side to prevent choking if unconscious, and have the medication bottle ready for paramedics. Treatment typically involves supportive care and may include the medication flumazenil, which can reverse benzodiazepine effects, though it's used cautiously due to seizure risks, as noted in the 2023 American Heart Association guidelines 1. Klonopin overdose is dangerous because it depresses the central nervous system, potentially causing respiratory depression and death, especially when combined with other substances like alcohol or opioids, as highlighted in the 2020 American Heart Association guidelines 1. The risk of overdose increases with higher doses, mixing with other substances, or in people with certain medical conditions. Key considerations in management include:

  • Establishing an open airway and providing bag-mask ventilation, followed by endotracheal intubation when appropriate 1
  • The potential use of flumazenil, but with caution due to the risk of precipitating seizures or dysrhythmias, particularly in patients with benzodiazepine tolerance or co-ingestion of other substances 1
  • The importance of considering concomitant opioid, ethanol, or other CNS depressant poisoning, and the potential need for naloxone administration 1

From the FDA Drug Label

Overdosage Human Experience: Symptoms of clonazepam overdosage, like those produced by other CNS depressants, include somnolence, confusion, coma, and diminished reflexes. The effects of a Clonazepam (Klonopin) overdose include:

  • Somnolence
  • Confusion
  • Coma
  • Diminished reflexes These effects are similar to those produced by other CNS depressants. It is also noted that serious sequelae are rare unless other drugs or alcohol have been taken concomitantly 2.

From the Research

Effects of Clonazepam Overdose

  • The effects of a Clonazepam overdose can be severe and potentially life-threatening 3, 4, 5
  • Symptoms of Clonazepam overdose may include central depression, ataxia, lethargy, coma, and respiratory depression 3, 5
  • In severe cases, Clonazepam overdose can lead to seizures, particularly in patients who have co-ingested other substances such as tricyclic antidepressants 4

Treatment of Clonazepam Overdose

  • Flumazenil is an effective antidote for Clonazepam overdose, but its use is associated with a risk of seizures 3, 4
  • Hemoperfusion may also be used in conjunction with flumazenil to alleviate symptoms of Clonazepam overdose 3
  • Supportive care, including activated charcoal administration and monitoring of vital signs, is also an important part of treating Clonazepam overdose 5
  • In some cases, endotracheal intubation may be necessary to manage respiratory depression 5

Clinical Findings and Outcomes

  • Children hospitalized for Clonazepam overdose may exhibit symptoms such as ataxia, lethargy, and coma 5
  • The duration of symptoms is typically less than 24 hours, but can vary depending on the severity of the overdose 5
  • With prompt treatment, most patients can recover from Clonazepam overdose without long-term consequences 3, 5

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Pediatric benzodiazepine ingestion resulting in hospitalization.

Journal of toxicology. Clinical toxicology, 1998

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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