A team of researchers in Colorado found that people who regularly use cannabis require more sedatives and anesthesia before routine medical procedures.
The study, published in the Journal of the American Osteopathic Association analyzed the medical records of 250 people who had colonoscopies.
Of the 25 people who reported using cannabis on a daily or weekly basis, the researchers say they needed higher doses of drugs and anesthesia to achieve optimal sedation.
On average, cannabis users needed 14 percent more fentanyl, 20 percent more midazolam, and 220 percent more propofol before colonoscopies and other routine medical procedures. The researchers say this finding is significant because higher doses often means a higher likelihood of negative - and potentially dangerous - side effects.
"Some of the sedative medications have dose-dependent side effects, meaning the higher the dose, the greater the likelihood for problems. That becomes particularly dangerous when suppressed respiratory function is a known side effect," said lead researcher Mark Twardowski, an osteopathic internal medicine physician in Grand Junction, Colo.
In colonoscopies, which made up the majority of cases the researchers reviewed, midazolam and propofol are the most commonly used sedatives, and fentanyl is a frequently used as a painkiller. Because the researchers only studied marijuana's impact on these three drugs, it's unknown if marijuana would interact with other sedatives on the market.