How does buprenorphine's affinity for the mu opioid receptor compare to heroin?

Buprenorphine has a greater affinity for the mu opioid receptor compared to heroin. This means that buprenorphine is more effective at binding to these receptors, which play a critical role in pain relief and the addictive properties of opioids. As a partial agonist at the mu receptor, buprenorphine activates the receptor but to a lesser degree than full agonists like heroin. This partial agonism helps reduce cravings and withdrawal symptoms in individuals with opioid use disorder while simultaneously diminishing the euphoric effects that can lead to misuse.

The greater affinity of buprenorphine also allows it to displace other opioids, such as heroin, from the receptors, which can be an essential factor in treating addiction. Since it competes effectively for the mu receptor, it can prevent the onset of the euphoric effects that patients might experience from using other opioids, thus supporting the goals of Medication-Assisted Treatment.