Retention of efficacy is the concept that medications will continue to be therapeutic without increasing the dose. Historically, long-term opioid treatment creates tolerance to opioids. However, I have clinically found that patients using very low doses of opioids combined with cannabinoids tend to have retention of efficacy. In mouse models, opioid receptors are actually upregulated in animals that are treated with both morphine and THC (the main psychoactive component of cannabis). This is the opposite of what happens when they’re treated with morphine alone. Mice maintain efficacy and avoid tolerance, as long as the dosage of opioid is maintained low.
Res Social Adm Pharm. 2016 Jul-Aug;12(4):638-54. doi: 10.1016/j.sapharm.2015.09.002. Epub 2015 Sep 16.
