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Risks / Side-effects

Potential side-effects of Cannabis-Based Medicinal Products (CBMPs) are minimal with CBD, and greater with THC.

Most common: Dry mouth, dizziness, drowsiness and disorientation

Others: Euphoria, unsteadiness, hallucinations, nausea, paranoia, anxiety, depression, psychosis

Cannabis Hyperemesis Syndrome: Nausea/Vomiting associated with excessive long-term THC exposure. Fortunately very rare, but may result in serious/fatal complications from dehydration.

To minimise potential side-effects, always

'Start Low and Go Slow'

Contra-indications (THC): Mania; cannabis use disorder; history/first-degree relative of psychosis

Contra-indications (all CBMPs): Pregnancy/breastfeeding

Relative contra-indications: Post-MI/stroke; cardiac arrhythmia; liver cirrhosis

Interactions (THC): With drugs affecting liver enzymes - notably CTP2C9/2D6

Interactions (CBD): With drugs affecting liver enzymes - notably CTP2C19/3A4 

Interactions (Other): As botanical medicines and unlicensed medicines with hundreds of chemical elements, CBMPs lack the research evidence to conclusively assess all potential interactions, side effects and long-terms risks.


Cannabis Dependency: Rare in Medical Users 

Lung Cancer: Not when using vaporiser 

Cognition: No long-term impairment in fully-developed adults  

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