Effectiveness of Placebos May Depend on Cannabinoid Pathways

The human body may use the cannabinoid pathway to make placebos effective, according to a Wired report based on a study from Nature Medicine.

According to the report, placebo-activated opioid analgesia does not work all the time. Researchers can induce it by giving a subject painful stimulus and then administering an opioid. Then, after this has been done several times, the researchers give the patient a placebo, which has been shown to effectively block the pain.

Researchers can also inhibit the placebo's action by giving the subject an opioid antagonist like naloxone, which blocks the effect of opioids. However, if researchers use a nonsteroidal anti-inflammatory like ibuprofen to create a placebo analgesic effect, the drug cannot be blocked with naloxone. This means that new pathways must exist that play a role in the analgesic effect of placebos.

The study measured subjects' pain response to a tourniquet on five non-consecutive days and found that the cannabinoid rimbonant blocked the placebo effect. The results suggest that cannabinoids play an important role in non-opioid preconditioned placebo effects.

Related Articles on Anesthesia:
Washington Surgeon Suspended Over Patient Death From Anesthetic
University of Virginia's Pain Center Continues Pioneering Tradition
Anesthesiologist Dr. David Dugan Joins Board of Kansas' Providence Medical Center

© Copyright ASC COMMUNICATIONS 2012. Interested in LINKING to or REPRINTING this content? View our policies by clicking here.