Introduction: Clonazolam is a designer benzodiazepine that can be purchased illicitly on the internet. The use of designer benzodiazepines is increasing in both the United States and abroad, and patients may present to the emergency department (ED) after intentional or non-intentional overdose.

Case report: This case report describes a patient who presented to a community ED after an intentional overdose on liquid clonazolam and was successfully treated with flumazenil.

Conclusion: Since the pharmacologic action of clonazolam is similar to benzodiazepines, the sedative-hypnotic effect can be reversed with flumazenil, a benzodiazepine antagonist.