The questions individuals often ask themselves regarding cannabis, and more specifically, regarding cannabidiol (CBD), are about the possible side effects of CBD. In order to give a valid answer to these doubts, it is important to start from the bases, namely from the substance in itself and from its mechanisms of action.

Cannabidiol (CBD) is one of the main active principles of the cannabis plant. It hasn’t got any psychotropic effect, unlike Delta-9-tetrahydrocannabinol (THC), another active principle.

Cannabidiol acts indirectly on the receptors of the endocannabinoid system and modulates mechanisms activated in the organism. When a situation of imbalance or decompensation of the endocannabinoid system is occurring (like during an inflammatory process) CBD tends to recover the original balance.

This is the reason for which cannabidiol is getting more popular each day: the indirect modulation of an alteration in the human endocannabinoid system caused by pathologies or traumas.  

The report of the World Health Organization (WHO) published in 2018 demonstrated that there are no significant adverse effects on human health, but, rather, showed the various medical applications of CBD.

According to the WHO report, cannabidiol has a good safety profile and is well-tolerated by human beings as well as by animals. Moreover, again according the report,  CBD hasn’t got any psychoactive effect, does not elicit physical dependence and is not associated to any negative effects on public health. In spite of the reassurances published both by the World Health Organization and by a revision drawn up by researchers of the Harvard Medical School, some studies presented in the past few years also reported some possible side effects.

CBD and excessive dryness of the mouth

In a research done in 1986 by personnel of the department of pharmacology and toxicology at the University of Arizona, the effects of CBD were investigated on five patients affected by dystonia: a mobility difficulty caused by entirely involuntary postural behaviour of the individual.  

The patients were administered oral dosages of CBD: from 100 to 600 milligrams daily over a period of six weeks. An important improvement in dystonia was observed but some side effects were noted, like a marked dryness of the mouth. According to the research, the dryness was due to the cannabinoid receptors present in the submandibular glands, which are responsible for the production of saliva.

In 2017 researchers from the University of Nottingham wanted to investigate the potential cardiovascular benefits of CBD on human beings and, in particular, the possibility of cannabidiol to diminish blood pressure.

The investigation, conducted on 9 male adults, demonstrated excellent results: CBD reduces blood pressure during rest and is also able to reduce it in case of severe stress. However, the authors also reported how some individuals had the sensation of dizziness, probably due to the lowering of their blood pressure.

CBD and sleepiness

Some studies, aimed at the investigation of the various effects of CBD on human beings, demonstrated the possibility that it can elicit sleepiness, as reported in an article of the Harvard Medical School.

However other investigations reported that cannabidiol can, equally, be a very useful ally for those suffering from insomnia. Due to these findings, many – physicians and  healthcare professionals – advise against taking CBD before engaging in activities requiring particular attention, like driving a car or a hazardous job.

CBD, metabolism and interaction with hepatic drugs

Cannabidiol has an effect on metabolism and could in particular have an effect on medical drugs taken for some pathologies of the liver. These drugs, in general, are metabolised by an enzyme called CY3A4, the same intervening in metabolism of CBD.

This implies that some drugs aimed at inhibiting this enzyme, can slow down the absorption and the breakdown of CBD. Other medicines, on the other hand, increase the levels of this enzyme and CBD, as a consequence, is broken down much quicker. In case of individuals with liver pathologies treated with specific drugs, it is necessary to consult their physician in order to assess the possible interaction with CBD.

CBD: safety and responsibility of the individual

Cannabidiol has got an excellent safety profile, confirmed also by the latest revisions of studies conducted up to now. Each individual, however, has to make a responsible choice in order to prevent, in any case, any possible side effect whatsoever.

In the studies that were taken into consideration, very often the researchers administered the participants extremely high dosages of cannabidiol, which would under no circumstances be taken normally. In case an individual desiring to try products containing CBD, is also treated with specific medicines, he or she should consult their physician in order to assess the situation as a whole.