Precautions
The precautionary principle
CONTRAINDICATION WHEN USING MEDICINAL CANNABIS
When considering cannabis as a therapeutic option, some groups of patients should be cautious or even avoid consuming cannabis. Remember, your doctor's instructions should always be followed.
Pregnancy/breastfeeding
The use of cannabis during pregnancy should be avoided. Cannabinoids will reach the foetus through the umbilical cord and may slow foetal growth and affect the development of the nervous system. Cannabis should also be avoided during breastfeeding, as it is detected in breast milk[1].
Combination with other CNS depressant substances
When using cannabis in combination with other substances that have a depressant effect on the central nervous system (CNS) – such as alcohol, benzodiazepines and opiates – there may be an additive tranquillising effect[2,3].
Children/adolescents
Cannabis, especially with a high THC content, should not be used by anyone under the age of 25 unless the benefits outweigh the risks, as the use of cannabis in this patient group can affect the way the brain matures and lead to long-lasting effects on cognition and an increased risk of psychotic disorders and dependence[3,4].
Elderly
Data on the use of cannabis by elderly patients are very limited. Age-related factors, such as reduced balance, slower metabolism by the liver and cardiovascular diseases, should be considered when administering cannabis to this patient group[3].
Psychiatric disorders
Patients with a personal history of psychiatric disorders (particularly psychosis and schizophrenia, but also mood disorders) or a familial history of schizophrenia should be cautious when using cannabis products, particularly with a high THC content. Care should also be taken in the case of patients with a history of abuse of alcohol, medicines or illicit drugs, as the risk of cannabis abuse for these individuals is higher[3,5].
Cardiovascular diseases
THC may cause tachycardia (accelerated heart rate) and orthostatic hypotension (low blood pressure when standing up). Caution should also be exercised for patients with pre-existing cardiovascular diseases[2].
Liver or renal diseases
Patients with severe liver or kidney impairment should exercise caution when using cannabis, as there is a lack of data on the potential accumulation of cannabinoids due to chronic usage[3].
References
Grant, K. S., Petroff, R., Isoherranen, N., Stella, N. & Burbacher, T. M. Cannabis use during pregnancy: Pharmacokinetics and effects on child development. Pharmacology and Therapeutics vol. 182 133–151 (2018).
Cannabisbureau.nl. Information for pharmacists and healthcare professionals. (2021).
Health Canada. INFORMATION FOR HEALTH CARE PROFESSIONALS. Cannabis (marihuana, marijuana) and the cannabinoids. (2018).
Felice, M. de & Laviolette, S. R. Reversing the Psychiatric Effects of Neurodevelopmental Cannabinoid Exposure: Exploring Pharmacotherapeutic Interventions for Symptom Improvement. International Journal of Molecular Sciences 22, (2021).
Lowe, D. J. E., Sasiadek, J. D., Coles, A. S. & George, T. P. Cannabis and Mental Illness: A Review. European archives of psychiatry and clinical neuroscience 269, 107 (2019).