GHB Dose and Effects – Therapeutic and Recreational Use By Dr Jonathan Karro

Posted on: June 18, 2019
Last Updated: November 24, 2023

Dr. Jonathan Karro is an Emergency Physician and Clinical Toxicologist. He is the Clinical Director of Emergency Medicine at St Vincent’s Hospital Melbourne and Honorary Senior Lecturer at the University of Melbourne. Jonathan completed a Sabbatical and Masters in Clinical Toxicology in 2012 working with the Victorian Poisons Information Centre and Austin Toxicology Service. His most significant area of toxicology research has been in the optimal sedation of the agitated/behaviorally disturbed ED patient.

Author Quotes:  

One thing quite novel about GHB is that it’s got such a narrow therapeutic index. The amount taken to have a good time for the desired effect is about one gram, and to induce coma might just be four or five grams. So there is a very narrow therapeutic index and when people are taking things in liquid, a few extra drops goes a long way and people overshoot the mark commonly.

The most common syndrome we see in the emergency department is a coma. The patient usually arrives profoundly comatose…but to the user they just call the ‘g-ing out’ and if you look at these drug forums saying that you just to sleep it off, as we will see, that might not be the best thing that you can do.

Summary and slides:  

Dr. Karro begins his presentation with a background to the biochemistry of GHB and its therapeutic uses. 

He describes its use, the effects of the drug, and the dose required for a specific desired effect in the user. 

He covers the pharmacokinetics and the narrow therapeutic index of the drug.

Moving on to talk about the culture of GHB and where it is most commonly used, Dr. Karro also lists all the different names the drug is known by. 

He describes his experiences in the emergency department of GHB-induced coma and the dangers associated with vomiting in these patients. 

Ending this first video excerpt, the clinical course is discussed further highlighting how good supportive care ensures these patients are often quickly treated with good results. However, anyone who is still very sleepy after 5-6 hours requires an alternative diagnosis. 

Take-home Points:  

  • A dose of 1-3 g of GHB can only be detected in serum for eight hours and in urine for about 12 hours, making allegations of drug-assisted sexual assault problematic. 
  • Therapeutic uses of GHB include obstetrics, anesthesia, narcolepsy, and opiate/alcohol withdrawal. 
  • Deaths from GHB use are rare but not unheard of. 


Learn more

  1. GHB – Informing Clinical Practice By Dr. Jonathan Karro