- Design
- Single-centre retrospective cohort
- Population
- 341,199 adults having propofol sedation or volatile general anaesthesia, 2008–2024
- Primary outcome
- Propofol dose and age-adjusted MAC
- Effect
- Non-medical users +6.85 µg/kg/min propofol (6.07–7.63); +0.01 MAC
This single-centre US retrospective cohort included 341,199 adults having propofol sedation or volatile-based general anaesthesia between 2008 and 2024; 7% were recorded as non-medical cannabis users and 0.9% held medical cannabis certification.
After adjustment, non-medical users received 6.85 µg/kg/min more propofol during sedation (95% CI 6.07–7.63), rising to 8.41 for daily users; medical users received 2.87 more. Volatile requirements were higher by only 0.01–0.02 MAC. Non-medical users had a slightly greater heart rate rise after intubation (+1.45 beats/min).
The effects are statistically clear but clinically small, and smaller than earlier reports suggested. Recording of cannabis use in the notes is likely to be incomplete, which would tend to blur the difference. In practice, asking about cannabis remains useful for anticipating harder sedation, but dosing should still be titrated to effect.
- Ask about cannabis use, including frequency, at preoperative assessment.
- Expect slightly higher propofol requirements in daily users during sedation.
- Titrate to effect; average differences in volatile requirement were negligible.
- Medical cannabinoid users showed smaller increases than recreational users.
Why it matters
It tempers the belief that cannabis users need dramatically more anaesthetic.
Don't overread it
Observational and single-centre; cannabis use was probably under-recorded.
The statistics, in plain English
An extra 6.85 µg/kg/min of propofol is a small fraction of typical sedation infusion rates — measurable, but modest. Very large cohorts can make small differences highly significant.
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