Cannabis: Recommended CBD dosage has been reduced in the UK because of safety concerns

Since 2018, when the British parliament passed a law legalizing CBD, the non-psychoactive ingredient of cannabis, sales of CBD-related products have skyrocketed. Nowadays, you can buy CBD oil, CBD vape pens, CBD coffee, CBD muffins to go with your CBD coffee everything. And these products are often sold with vague promises of improved health.

As CBD, in this context, is not a medicine, it is not regulated by the UK’s medicines regulator but by the Food Standards Agency (FSA). In 2020, the FSA recommends that daily CBD consumption should not exceed 70mg. The FSA and Food Standards Scotland have now reduced this limit to 10mg, equivalent to four drops of 5% CBD oil.

To be clear, 10mg is the recommended safe limit. You won’t be caught if you consume more than 10mg a day, but the agency warns that there could be long-term health effects if you ignore advice that it is harmful to the liver and thyroid.

The effects of CBD have been tested on a variety of conditions, from schizophrenia to anxiety, with mixed results. When benefit has been demonstrated, it has often been at much higher doses, about five times the previously recommended maximum intake.

The new 10 mg recommended limit has nothing to do with the drug’s effectiveness at this dose as no effect has been demonstrated. The move to a lower recommended dose comes after several studies indicated that CBD may not be as harmless as previously thought.

To determine the toxicity level of a substance, or rather, the highest safe amount that humans can consume in a certain period of time, scientists test it on animals and then apply ‘adjustment level’.

For example, if, in a study using rats, a dose of 100mg/kg body weight was found to be the highest dose that showed no harm, that would mean that a 70kg person would consume 7g per day. .

However, there are differences in metabolism between species, with humans potentially more susceptible.

Accidentally increased dose

It’s worth noting that seemingly harmless foods, such as grapefruit, broccoli and well-done steak, can interfere with the metabolism of certain drugs. It is known that rifampicin, a widely prescribed antibiotic, can interfere with the metabolism of CBD. Other medications should be closely monitored for potential interactions.

There is also a risk of increasing the dose too high when taking CBD with other medications, such as ketoconazole (a medication to control fungal infections), and even increased absorption when taking CBD with fatty foods . That’s why it’s not uncommon for drug safety experts to apply a 400-fold correction factor to previously calculated values. That would reduce the allowable intake from 7g a day to just 17.5mg a day.

Using several animal studies of CBD that showed similar values ​​and correction factors, new recommended levels were recently published. That is the job of public bodies: to show, based on the best possible evidence, whether a department can do what it is supposed to do and not cause harm in doing so.

It is important to emphasize that the FSA’s recent announcement is not a ban. You can still buy drinks that contain CBD in excess of the new daily limit in one serving. However, any new products will need – as before – to be approved by the FSA, which may be more difficult with this new limit. Ensuring safety, especially for a substance that appears to offer little benefit, is rightly the agency’s top priority.

Julio de Carvalho Ponce, Lecturer in Forensic Science, University of Winchester

This article is republished from The Conversation under a Creative Commons license. Read the original article.