“Because cannabinoid receptors, unlike opioid receptors, are not located in the brainstem areas controlling respiration, lethal overdoses from Cannabis and cannabinoids do not occur.”
n other words, marijuana and opioids affect different pathways of the body. Opioid pathways, also known as receptors, are present in areas of the brain that control breathing. As a result, taking too many painkillers can cause a person to stop breathing.
But marijuana acts on a completely different set of pathways. These pathways are called cannabinoid receptors and they do not affect respiration. Thus, marijuana cannot cause someone to stop breathing, no matter how much they ingest.
Another way of measuring a drug’s safety is by its therapeutic index. The therapeutic index is the ratio between a drug’s lethal dose and its therapeutic dose (amount that causes a therapeutic effect).
Studies show that marijuana has a therapeutic index of 40,000:1. This means someone would have to take 40,000 times the normal amount of marijuana in order to die.
Opioid-based painkillers have much lower therapeutic indexes. For example, the therapeutic index of morphine is only 70:1.