From the Guidelines
Cannabinoid hyperemesis syndrome, also known as "greening out," is primarily caused by the stimulation of central CB1 receptors by THC, leading to increased vagal nerve discharges and subsequent vomiting, as supported by the most recent evidence from 2024 1. The pathophysiology of this condition involves the activation of CB1 receptors in the brain and gut, which are densely distributed in areas controlling emesis, such as the dorsal vagal complex. This activation can lead to loss of negative feedback on the hypothalamic–pituitary–adrenal axis, resulting in increased vagal nerve discharges and contributing to vomiting. Key factors that contribute to the development of cannabinoid hyperemesis syndrome include:
- Heavy and prolonged cannabis use
- Daily cannabis use
- Concurrent use of other substances, such as tobacco
- Younger age
- Psychiatric comorbidity
- Symptoms compatible with other disorders of gut–brain interaction The clinical diagnostic criteria for cannabinoid hyperemesis syndrome include:
- Cyclic vomiting, nausea, and abdominal pain
- Prolonged bathing behavior, such as taking long hot baths or showers
- Chronic nausea and vomiting in patients with a history of cannabis use It is essential to suspect cannabinoid hyperemesis syndrome in patients with chronic nausea and vomiting and cannabis use, as supported by the evidence from the 2024 study 1.
From the Research
Causes of Cannabis-Induced Poisoning
- Cannabis-induced poisoning, also known as greening out or cannabinoid hyperemesis syndrome, is a condition that can occur with chronic use of cannabis 2.
- The exact cause of this condition is not fully understood, but it is thought to be related to the psychoactive effects of tetrahydrocannabinol (THC), the main active ingredient in cannabis.
- Adverse effects of cannabis can include fear, distrust, hallucinations, ataxia, stupor, and seizures, and long-term use can result in respiratory and cardiovascular toxicity 2.
Symptoms and Treatment
- Symptoms of cannabis-induced poisoning can include nausea, vomiting, and abdominal pain, which can be severe and debilitating.
- Treatment of acute intoxication mainly consists of supportive care, and children may require additional supportive care due to their increased susceptibility to cannabis toxicity 2.
- Antiemetic medications such as ondansetron and metoclopramide may be effective in treating nausea and vomiting associated with cannabis use, but their effectiveness has not been specifically studied in the context of cannabis-induced poisoning 3, 4, 5, 6.
Related Research
- Studies have investigated the antiemetic effects of ondansetron and metoclopramide in various clinical settings, including postoperative nausea and vomiting, minor head trauma, and undifferentiated emergency department nausea and vomiting 3, 4, 5, 6.
- These studies have shown that ondansetron and metoclopramide can be effective in reducing nausea and vomiting, but their effectiveness may vary depending on the specific clinical context and patient population.