What Is A Lethal Dose Of Klonopin (Clonazepam)?

Klonopin (clonazepam) is a prescription sedative and central nervous system (CNS) depressant. People who abuse Klonopin often combine it with alcohol, opioids, or other substances to intensify their effects. Taking an extremely high dose of Klonopin, or mixing it with other CNS depressants can be fatal.

A typical dose of Klonopin is 0.5 mg. When taken in excess alongside other drugs or alcohol can result in symptoms such as confusion, dizziness, slow reflexes, slurred speech, and other signs of overdose. If someone has taken a lethal dose of Klonopin, call 911 or seek emergency medical attention right away. Klonopin is rarely fatal on its own, but can be deadly mixed with drugs.

Learn more about the lethal dose of commonly abused drugs.

How A Lethal Dose Of Klonopin Is Determined

Clonazepam is rarely associated with fatality when taken on its own. Even instances of taking very high doses of Klonopin, more than 20 milligrams (mg), or 45 tablets, have resulted in recovery with prompt medical treatment. The recommended daily dose of Klonopin is no more than 1.5 mg. In rats, lethal doses of Klonopin have been recorded at 4,000 mg/kg of weight.

Mixing Clonazepam And Opioids Can Be Fatal

While rarely fatal on its own, Klonopin can be deadly in combination with other depressants, including alcohol and opioids. According to the National Institute on Drug Abuse (NIDA), almost 11,000 opioid overdose deaths in 2023 involved benzodiazepines such as Klonopin.

Mixing sedatives (like benzodiazepines) with opioids can drastically heighten the risk of respiratory depression, which is often the cause of death in these overdoses. Both drug classes suppress the central nervous system, and when combined, they can overwhelm the body’s ability to maintain vital functions like breathing.

Factors That Can Affect The Lethal Dose Of Klonopin

The lethal dose of Klonopin can vary dramatically from person to person due to numerous personal and biological factors that influence how the body processes and responds to the medication.

Factors that can affect the lethal dosage include:

• Age: elderly people are at much higher risk because their bodies process medications more slowly, and they often have other health problems that make them more vulnerable to the toxic effects of benzodiazepines
• Drug Tolerance: people who have been taking Klonopin regularly may survive higher doses than those who rarely use it, but tolerance also leads people to take dangerously large amounts to achieve the desired effects
• Use of Multiple Drugs: combining Klonopin with alcohol, opioids, or other sedatives dramatically increases the risk of fatal overdose
• Method of Use: taking Klonopin orally as prescribed is safer than crushing and snorting it or dissolving it for injection, which can cause faster absorption and more intense effects
• Body Composition: people with less body mass typically experience stronger effects from the same dose, while factors like body fat percentage can affect how long the drug stays in the system
• Drug Metabolism: some people break down medications faster or slower due to genetic differences, meaning the same dose can have different effects on different individuals
• Liver Function: since the liver is responsible for processing Klonopin, people with liver disease or damage may experience toxic buildup of the drug even at normal doses
• Kidney Function: impaired kidney function can prevent the body from properly eliminating Klonopin, leading to dangerous accumulation in the bloodstream

Get matched with an affordable mental health counselor

Find a Therapist

Answer a few questions to get started

As a BetterHelp affiliate, we receive commissions if you purchase through the BetterHelp links above.

Ad

Taking Klonopin with other depressants is the number one predictor of Klonopin overdose. When this happens it is a medical emergency requiring immediate medical care, regardless of the amount taken or the person’s previous experience with the medication.

Recognizing The Signs Of A Klonopin Overdose

Overdose involving Klonopin or Klonopin with other drugs can be treatable with prompt medical attention. Knowing the signs of a drug overdose can be life-saving.

Signs and symptoms of Klonopin overdose include:

• extreme drowsiness
• very slow or shallow breathing
• difficulty breathing
• confusion
• slurred speech
• dilated pupils
• very fast or slow pulse
• impaired balance
• loss of consciousness

If someone has collapsed, stopped breathing, or is unresponsive after taking a high dose of Klonopin, call 911 right away.

What To Do During A Klonopin Overdose

A Klonopin overdose is a medical emergency that requires immediate action. If someone appears to be overdosing, call 911 and do not leave them alone. If the person is unconscious but breathing, turn them onto their side to prevent choking in case they vomit, and monitor their breathing closely until help arrives.

Be honest with emergency responders about everything the person has taken, including any other medications, alcohol, or substances consumed alongside Klonopin. This information is critical for determining the most appropriate course of treatment. If naloxone is available and opioids may also have been involved, administer it while waiting for help.

Written by the Addiction Resource Editorial Staff