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Unfortunately there isn’t a simple answer to this question.
Donating blood can potentially save someone’s life. It’s a super safe procedure, but around 58% of British people have never done it. There could be many reasons why this number is so high, one of them being the criteria that blood donors must meet.
The NHS Blood and Transplant (NHSBT) are in charge of blood donations in the UK. Making sure donated blood comes from eligible and safe donors is their responsibility. And to protect the health and safety of donors and recipients, they have strict guidelines and eligibility criteria to determine who can donate blood.
We’ll explore medical cannabis patients and blood donation in the UK, and the effects of cannabis on blood donation below.
Can You Donate Blood If You Use Cannabis?
Cannabis and blood donation rules aren’t straight-forward. But there are a few clear dos and don'ts to giving blood in general, listed on the NHSBT website.
If you’re looking to donate blood you must:
- Be healthy
- Be between the ages of 17 and 65
- Weight between 50 kg and 158 kg
- Have suitable veins - this is checked before you donate
- Meet the eligibility criteria
You can’t give blood if you:
- Have had certain types of cancer
- Have a heart condition
- Have received blood products after 1st January 1980
- Have HIV
- Have had an organ transplant
- Are a hepatitis B or C carrier
- Have injected non-prescribed drugs
Currently, medical cannabis patients are not allowed to donate according to NHSBT's eligibility criteria for blood donation.
Factors That Influence Eligibility
Whether you have a medical cannabis prescription or not, everyone goes through a health screening before donating blood. This is to make sure it’s safe for you to donate, and your blood is safe for a patient to receive. It involves:
- Confirming your identity
- Going through the information on your donor health check form
- Following up with a registered nurse (if necessary)
- Testing a drop of blood from your finger
If you’re not eligible to donate, someone will explain why. But, you should be able to rebook your appointment - it likely depends on the reasons behind why you can’t donate on the day.
Effects of Cannabis on Blood Donation
Medical cannabis has been fully legal in the UK since 2018. But despite this, there are still misconceptions surrounding its use. A lot of misinformation about the plant has been put out into the world, and this has led a lot of people to see it as an illicit drug rather than a medicine.
Unfortunately there just isn’t enough research around cannabis as a medicine. And it’s potentially that fear of the unknown that is a big contributing factor behind why using cannabis can sometimes prevent someone from donating blood. This lack of awareness on the therapeutic benefits is why clinics like Alternaleaf are working hard to highlight why it can be so beneficial.
Another potential concern some people may have is that cannabis is known to be behind that ‘high’ feeling. THC is a cannabinoid or compound in the cannabis plant that can cause this effect if the dose is high enough. However, it’s unlikely you’ll be prescribed cannabis medication in a way that will make you feel ‘high’, and it’s as safe as many other over-the-counter medications as long as you’re using it against your prescription guidance.
Research continues to happen right now, and hopefully more people will be made aware that medical cannabis products are rigorously tested and quality-controlled.
Can medical cannabis patients donate blood in the UK?
On the NHSBT website it states that anyone under the influence of cannabis cannot donate blood. The website goes on to explain their reasons are that providing reliable history and giving valid consent may be disrupted by the use of cannabis. They state it could also increase the risk of fainting, feeling dizzy or light-headed. So, ultimately, they’re putting your safety first.
However, it does also state under ‘taking medication’ that whether or not you’re eligible to donate blood can depend on what medication you’re on and what you’re being treated for. For example, if you’re on certain antibiotics, you can donate if you wait a certain amount of time after your last tablet.
The same has been known to be true for medical cannabis. Some patients have shared on community forum websites, like Reddit, that they have been able to donate blood, even with a medical cannabis prescription. As long as they’re not under the influence at the appointment, it seems like there’s no issue. However, this can be very subjective. To some people this could mean having no medication in their system, to others it could mean having lower levels. So, it may be a good idea to be aware of this.
The problem is, this isn’t stated as a rule or guideline on the NHSBT website, so could change at any time. These patients may have just got lucky with who they’ve spoken too, so it’s still a good idea to go in prepared for a no if you’re hoping to give blood whilst on a medical cannabis prescription.
Hopefully with more research to back the benefits of medical cannabis, these rules and guidelines will change.
Summary
Ultimately it comes down to which healthcare professional you end up speaking to when it comes to medical cannabis (also known as marijuana) and blood donation as it’s unclear whether or not you can donate blood under the guidelines laid out. And, as long as you’re not under the influence during or before your appointment, there’s no reason you shouldn’t be able to give blood. Maybe just prepare for a no.
That being said, this doesn’t apply to those using cannabis recreationally. We’re talking about people who use Alternaleaf, and are prescribed cannabis as a medication. When it comes to cannabis smoking and blood donation eligibility, it is illegal.
Hopefully in the future, with more research around medical cannabis and its therapeutic benefits, it’ll be recognised as the medication it is, and will be encompassed by the ‘taking medication’ guidelines on the NHSBT website.