THC Overdose Treatment: What Happens When You Go to the ER

In 30 years in the ER at Emory Healthcare, I've watched the conversation around cannabis shift dramatically. What hasn't shifted: what happens in the treatment room when a patient comes in with THC toxicity. Here is the clinical reality, in plain language.

What Is THC Toxicity?

THC toxicity, also called cannabis toxicity or acute cannabis intoxication, occurs when someone's system is overwhelmed by delta-9-tetrahydrocannabinol. This is not a theoretical concern. It is a presenting diagnosis in emergency departments across the country, including in pediatric cases.

The legalization of high-potency THC products, concentrates, edibles, and vapes has raised the ceiling on what a dose can look like. A dispensary gummy today is not the same THC exposure that existed 20 years ago. Concentrations have climbed significantly, and many products do not make dosing clear to consumers.

Triage: What We Check First

When a patient presents with suspected THC toxicity, triage begins with the basics: airway, breathing, circulation, and level of consciousness. The questions I'm asking in the first two minutes are:

• Is this person maintaining their airway?
• What is their breathing rate and depth?
• Are they responsive to verbal or painful stimuli?
• What is the heart rate and blood pressure?
• Is there any possibility of polydrug use, especially opioids?

That last question matters more every year. With fentanyl contamination present in the counterfeit pill and illicit vape market, a patient who appears to have THC toxicity may have been exposed to opioids without knowing it.

Monitoring in the ER

Most THC toxicity presentations are managed with supportive care. That means monitoring and waiting for the acute effects to resolve, while treating symptoms that are causing the patient distress or presenting a clinical risk.

We monitor: heart rate, blood pressure, oxygen saturation, and mental status at regular intervals. Tachycardia (elevated heart rate) is common with cannabis. Significant cardiovascular changes in older patients or those with cardiac history require closer attention.

Differential Diagnosis: What Else Could It Be?

The ER does not take a patient's reported substance use at face value. We build a differential diagnosis, which means we consider all the conditions that could produce the same presentation. For a patient who appears intoxicated, altered, or unconscious, the differential can include:

• Opioid overdose
• Benzodiazepine toxicity
• Synthetic cannabinoid toxicity (K2/Spice behaves very differently from THC)
• Hypoglycemia
• Head trauma
• Stroke
• Serotonin syndrome

We do not assume. We rule out. Labs, imaging, and clinical assessment determine the picture.

Treatment: What Actually Happens

There is no antidote for THC toxicity the way Narcan reverses opioid overdose. Treatment is supportive.

Depending on what the patient is experiencing, treatment may include:

• IV fluids if the patient is dehydrated from vomiting
• Anti-nausea medications (ondansetron is common) for severe nausea and vomiting
• Benzodiazepines in small doses for severe anxiety, agitation, or acute psychosis
• Cardiac monitoring if tachycardia is significant
• Quiet environment: reducing stimulation often helps with acute THC-induced anxiety

In most cases, a patient with pure THC toxicity will stabilize over several hours as the drug clears. Pediatric cases may require more intensive monitoring.

Cannabis Hyperemesis Syndrome

A subset of heavy cannabis users presents with a distinct pattern: cyclical, severe vomiting that does not respond to standard anti-nausea treatment, but is relieved by hot showers. This is cannabis hyperemesis syndrome (CHS). The paradox here, where a substance typically associated with nausea relief causes intractable nausea in chronic users, is not fully understood. The only definitive treatment is cessation of cannabis use.

Pediatric THC Toxicity

Pediatric cases deserve specific attention. A video I published about a 9-year-old treated for THC toxicity received 447,000 views. The clinical reality: edibles, vapes, and high-potency products accessible in homes have increased pediatric exposures significantly.

In young children, THC toxicity can present with altered consciousness, difficulty walking, and in severe cases, respiratory depression. Pediatric cases warrant immediate emergency evaluation. Do not wait to see if it resolves.

What Families Can Do

The ER is not the first responder. By the time a patient reaches us, several minutes have already passed. What a family does in those first minutes matters.

1. Call 911 immediately if someone is unconscious, not breathing normally, or cannot be woken.
2. Recovery position: lay them on their side to protect the airway.
3. Do not leave them alone.
4. Consider Narcan if there is any possibility opioids were involved. It does no harm if they weren't.
5. Stay on the line with 911. Follow the dispatcher's instructions.

Frequently Asked Questions