- Design
- Single-centre retrospective cohort, 2008 to 2024
- Population
- 341,199 adults receiving propofol sedation or volatile general anaesthesia
- Primary outcome
- Propofol infusion rate and age-adjusted end-tidal MAC
- Effect
- Non-medical use +6.85 µg/kg/min propofol (95% CI 6.07 to 7.63); +0.01 MAC
A single-centre retrospective cohort at a Boston teaching hospital examined 341,199 adults who had propofol sedation or volatile-based general anaesthesia between 2008 and 2024. Published in the British Journal of Anaesthesia on 29 September 2026.
Non-medical cannabis use, recorded in 7.0%, was associated with higher propofol infusion rates during sedation (+6.85 µg/kg/min, 95% CI 6.07 to 7.63) and slightly higher volatile requirements (+0.01 MAC). Medical cannabis use was associated with smaller increases. Daily recreational users had the largest difference (+8.41 µg/kg/min). After similar induction doses, cannabis users had a slightly larger heart rate rise at intubation (+1.45 beats/min).
This is observational and relies on recorded cannabis use, which is likely under-reported. The differences are statistically clear but small, smaller than earlier case series suggested. The practical point is to ask, expect a modest increase in requirement in frequent users, and titrate rather than pre-emptively escalate. Cannabis and bhang use may go unmentioned unless asked about directly.
- Ask about cannabis use, including frequency and route, at preoperative assessment
- Expect a modest rise in propofol and volatile requirement in daily users
- Titrate to effect and depth monitoring rather than giving larger fixed doses
- Watch for a slightly greater heart rate response at intubation
Why it matters
It replaces anecdotes of large dose increases with a measured, smaller figure.
Don't overread it
An association from one centre's records; it does not establish that cannabis causes higher requirements.
The statistics, in plain English
An extra 6.85 µg/kg/min of propofol is small relative to usual sedation infusion rates. With over 300,000 patients, even tiny differences reach statistical significance, so clinical relevance needs judging separately.
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