Medical Cannabis Side Effects & Safety

Medical Cannabis is extremely safe overall, and most people tolerate it well.

With all medicines there are certain safety aspects that need to be considered - who can't have medical cannabis? What are the potential side effects? Or how does it interact with other medicines. I've put some answers to these questions below.

Medical Cannabis contains more than one cannabinoid. The two main cannabinoids are THC and CBD. THC has more potential side effects. Many of the potential side effects of THC can be counteracted by CBD. They are a good team!

Short term side effects may include disorientation, nausea, dizziness, euphoria, drowsiness, dry mouth, balance issues, hallucinations, fatigue, anxiety, gastric symptoms and very rarely psychosis (we'll look at that below).

Longer term side effects are more associated with long term use of illicit cannabis which is often much higher in THC. The main concern with long term use of high THC is schizophrenia and psychosis. For patients who already have a history of schizophrenia or psychosis, this risk is higher and in many cases a patient may not be suitable for THC if they have this history (CBD will be suitable). Those with a family history are also more at risk. Before any patient is prescribed medical cannabis they will be assessed by a consultant. In the case of patients with a history or risk of psychosis this assessment will be with a consultant psychiatrist and the patient will be regularly assessed.

Cannabis Dependency

Studies on cannabis dependency have mainly looked at the use of illicit/recreational cannabis. It is very rare for this to occur from prescribed doses of medical cannabis.

We are extremely careful to regulate and assess the ongoing doses of medical cannabis for patients, and we have a limit to the amount that will be prescribed.

We would prefer patients to take safely dosed medical cannabis rather than use illicit cannabis which has a higher unregulated amount of THC and no dosing limitations.

Addiction rates for cannabis are less than for alcohol, tobacco or prescribed opioids. Medical cannabis can be helpful in enabling patients to reduce their use of opioid medications.

As medical cannabis clinicians we treat this medicine the same as any other potentially addictive medicines we prescribe - continuous assessment, limitations and safe dosing.

When a patient cannot have medical cannabis...

Medical cannabis is not suitable for patients who are pregnant or breastfeeding.

There may be cases where a patient is not suitable for medical cannabis. A medical cannabis clinician will assess a patient before starting medical cannabis and identify any risks.

There may be some medications that patients are taking, which will interact with medical cannabis - a medical cannabis clinician will assess this and advise.