Regular Cannabis Use and a Requirement for More Anaesthesia

A Rise in Global Cannabis Consumption

The consumption of cannabis – for medical and recreational purposes – is no new feat. Records of marijuana consumption date as far back as at least 5,000 years ago. Physical evidence to support this claim was provided by Andrew Sherrat, an Oxford archaeologist. His findings include a gravesite of an ancient group of humans known as the Proto-Indo-Europeans – also known as the Kurgans – who occupied what we now know as Romani.

As the centuries progressed, cannabis consumption was labelled evil and many governments worldwide placed the plant on prohibition on a mass scale. The prohibition period of cannabis is noted to have begun with the Marijuana Tax Act of 1937 and reached its peak when cannabis was classified as a schedule one substance in the United States via the Controlled Substances Act of 1970.

In 2013, Uruguay became the first country to legalise the consumption of Marijuana. Following its footsteps, cannabis has become legal on state and federal level in countries including Canada and the United States. Following its legalisation, the consumption of cannabis has risen massively. According to the World Health Organisation, a whopping 147 Million people (About 2.5 of the world’s population) are known to consume cannabis. 

There are many studies that show the advantages of consuming cannabis. The chemical compounds in the cannabis plant – known as cannabinoids – are beneficial to the treatment of a myriad of diseases including cancer and multiple sclerosis. Although the consumption of cannabis is seemingly positive in the medical field, studies are beginning to show that regular cannabis consumers may require more anaesthesia when undergoing medical procedures.

A Study on Cannabis and Anaesthesia

A U.S study conducted in the state of Colorado suggests that individuals who consume cannabis regularly require more anaesthesia when undergoing medical procedures. This study was carried out by Mark Twardowski, a doctor of osteopathic medicine at Community Hospital – Grand Junction, Colorado. 

In this study, access was gained to the medical records of 250 patients. Twardowski and his team closely examined these patients who underwent minimally invasive procedures which required the administration of anaesthesia. Amongst the patients, 25 of them (10% of the group) were known to use marijuana regularly – via smoking and consuming edibles.

For this study, three separate anaesthetic medications were administered to the group. These anaesthetics were:

  • Midazolam
  • Fentanyl
  • Propofol

As conclusions on the study were drawn, it was noticed that cannabis consumers required more anaesthesia during procedures in comparison to non-cannabis users.  Cannabis consumers required 19.6% more midazolam, 14% more fentanyl and a whopping 220.5% more propofol than non-cannabis consumers.

Graphs Representing the Percentages of Anaesthetic Medication Administered. src

Understanding the Results

These results can be attributed to the interactions of tetrahydrocannabinol – the main psychoactive and dominant cannabinoid in the cannabis plant.

Tetrahydrocannabinol – also known as THC – is known to interact with the endocannabinoid systems in human. This interaction is known to alter certain bodily functions such as appetite. According to Twardowski, it is possible that the presence of cannabinoids in the system can suppress the activity of other receptors in the body, thereby influencing the way anaesthetic drugs interact internally. This, however, is all a guess at the time.

Twardowski notes that the study was indeed limited. This is due to a number of factors including the following:

  • Small Sample Size 
    The sample size represented in the study is relatively small. Conclusions drawn based on 250 people may not be sufficient enough to represent a wider demographic.
  • Retrospective Medical Records 
    Research was not carried out in real time. Twardowski and his team reviewed the past medical records of the group carefully before conclusions were drawn.
  • Honesty of Participants 
    Participants of the study were asked if they used marijuana regularly and their answers were factored in its conclusion. Due to the stigma associated with marijuana, it is possible that some participants were not honest about their marijuana usage. This can alter the conclusions drawn.

Asides these factors Twardowski also notes that there is very little research on the topic as Marijuana is still a schedule one substance in the United States.


The results of the study conducted by Twardowski and his team have drawn informative conclusions on the topic. However, to solidify this hypothesis, more research would need to be carried out by scientists and medical professionals alike. There is very limited base study on the topic as marijuana is still a schedule one drug in the United States. With the growing move to legalise marijuana on a federal level, more data may be available to draw definite conclusions on the topic. Until then, this study would just be an observation.

Published by Neil

Neil believes Cannabis has medical benefits and should be prescribed by a Doctor. This site aims to provide accurate information on the science and legality of Cannabis so you can make informed decisions.

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