The possible effects of medical cannabis on public health — a pharmacist's perspective, Part 1


Tuesday, July 11, 2017

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Cannabis is a generic medical term that refers to drugs derived from plants belonging to the genus cannabis.

Cannabis-based medicine refers to cannabis or cannabinoids used as medical therapy to treat disease or alleviate symptoms.

Hemp and marijuana are both cannabis.

Cannabis has an interesting legal status currently and a diverse historical legal status. Presently it is listed as a controlled substance (Schedule 1). Although many states allow for medical use, the US Schedule 1 Federal status does not allow for medical use.

So what does this mean for medical-legal states in the US?

Under the Supremacy Clause of the US Constitution, any state law that conflicts with a federal law is pre-empted by the federal law — meaning federal law trumps state law. However, change at the federal level is brewing as the current Administration has said state and federal laws need to be reconciled, and in language in the federal spending Bill has prohibited the US Department of Justice from using federal funds to undermine state laws regarding medical cannabis.

Let's look at the developing situations in the US since the legalisation of cannabis in some states:

Wilkinson et al writes: “As states continue to proceed with legalisation for both medical and recreational use, certain public health issues have become increasingly relevant, including the effects of acute marijuana intoxication on driving abilities, unintentional ingestion of marijuana products by children, the relationship between marijuana and opioid use, and whether there will be an increase in health problems related to marijuana use, such as dependence/addiction, psychosis, and pulmonary disorders. In light of this rapidly shifting legal landscape, more research is urgently needed to better understand the impact of legalisation on public health.”

Ghosh et al state about Colorado's public safety concerns with legalisation: “The first year of legalisation in Colorado has demonstrated the need for the continued engagement of public health in marijuana-related issues to promote timely policy changes as new health issues arise.”

A study about children's health and safety in regard to the legalisation of marijuana in Colorado showed an increase of emergency room visits in relation to marijuana ingestion and stated, “When these children arrived at the emergency department, symptoms ranged from sleepiness to difficulty breathing, or they were comatose. Nearly half of the children required care in the intensive care unit and some needed intubation.” (Children's Hospital Association)

However, in the same study, significant efforts and strides have been made to help decrease harm to children's health in regards to marijuana. The study continued to state, “In an effort to prevent accidental ingestion, George Sam Wang, MD, a paediatric emergency medicine physician and medical toxicologist at Children's Colorado, helped the state craft legislation in 2014 that required child-safe packaging for marijuana products. For decades, child-resistant packaging has been a proven method for keeping kids out of unsafe products. Almost all pharmaceuticals and household products meet the standards.” (Children's Hospital Association)

According to Li et al, “Results of this meta-analysis indicate that marijuana use by drivers is associated with a significantly increased risk of crash involvement. Specifically, drivers who test positive for marijuana or self-report using marijuana are more than twice as likely as other drivers to be involved in motor vehicle crashes.”

However, the National Institute on Drug Abuse pointed out, “A large case-control study conducted by the National Highway Traffic Safety Administration found no significant increased crash risk attributable to cannabis after controlling for drivers' age, gender, race, and presence of alcohol.”

Let's look at Jamaica's situation with regard to legalisation, as so far we have only done decriminalisation. Anthony Hylton, former industry and trade minister, in an op-ed in the Jamaica Observer, published Sunday, April 24, 2016, “Regarding the legalisation of ganja, the current Administration, like the previous one, recognises that this cannot be achieved without changes to Jamaica's international obligations under United Nations conventions. To that end, the Minister of Foreign Affairs and Foreign Trade led a delegation recently to the United Nations to participate in a conference to examine proposed changes to existing treaty laws. However, the conference concluded without the necessary reforms, which means that Jamaica (and all other nations) will have to continue to operate within the existing legal framework.”

This means we still have a way to go with legalisation, but until we get there, there are a few evidence-based findings that I want the public of Jamaica, being a community pharmacist, to be aware of in this article but not limited to the following.

A drug can be broadly defined as any man-made, natural, or endogenous (from within body) molecule which exerts a biochemical and/or physiological effect on the cell, tissue, organ, or organism. These interactions may alter normal or abnormal biochemical functions.

These effects may be beneficial or toxic.

If substances have beneficial medicinal properties, they are considered pharmaceuticals. If substances are considered therapeutic they fall in the definition medical pharmacology, if they have undesired effects they fall into toxicology. Let's now look at a few concerns that may impact public health in Jamaica.

Cannabis and attention

An important and somewhat controversial topic is the effects of cannabis on the ability to drive. We do know that peripheral attention is reduced in patients that are under the influence of cannabis. They may become absorbed in an object or event and not be thinking about anything else. This, by definition, would affect someone's ability to drive a car.

There are also some effects on memory and image perception, both short-term and long-term memory are slightly impaired. There are some hallucinogenic properties of marijuana that could cause somebody not to be able to see their environment unlike someone who is not under the influence. There's a slight effect on motor coordination. It's impaired, but much less than on alcohol or opioids.

We do know that in the United States of America the states that have legalised recreational use of marijuana have seen an increase in car accidents in the population, especially among those that combine alcohol and cannabis. Together the effects on the motor coordination and judgement given by the alcohol combined with the cannabis effects on peripheral attention leads to an increase in impaired ability to drive.

But, being able to tell what concentration in a bodily fluid effects impairment of driving is really not that well studied, and we don't understand it. And because of tolerance some patients who might be taking it medically may be perfectly legal to drive, except that they have the certain concentration of Tetrahydrocannabinol (the principal psychoactive constituent of cannabisin) in their bloodstream.

Those things really need to be worked out for the public safety. This may also have implications for motor vehicle insurances in Jamaica. Just imagine you answer 'yes' to a question on a motor vehicle insurance application that asks if you use cannabis. I am sure they may just ask you to pay a higher premium, just saying.

Cannabis and schizophrenia

Probably the most prominent public safety risk that is talked about is cannabis and schizophrenia, because the idea that smoking cannabis could lead to the development of schizophrenia is a very scary aspect and is oftentimes used by politicians to promote maintaining the illegality of cannabis. There are some pieces of data that do connect cannabis with schizophrenia, there is a lot of conflicting data, and in early onset chronic use there is pretty strong association data with the development of schizophrenia. There is almost no data that shows a cause and effect where the cannabis causes schizophrenia, and there has been a genetic analysis found that associates a person's schizophrenia risk with the potential use of cannabis. This means that it's the potential to be schizophrenic in the first place that leads to cannabis use and those patients are using cannabis to treat their early systems. So, patients will self-medicate with cannabis in order to treat their early schizophrenia symptoms.

Again, there is a lot more research that needs to be done in this area, and it does still exist as a potential problem and public safety risk. However, it only seems to be really relevant in young populations who are chronically using cannabis.

Next week I will concentrate on the impacts on adolescents.

Rohan McNellie is a registered pharmacist and a holds a professional certificate in cannabis science and medicine from the University of Vermont, USA. Send comments to the Observer or




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