Eli5: How do opiates cause constipation?

Question

My research has turned up reports that it slows bowel activity and causes too much water to be absorbed, but what does that have to do with relieving pain?

In: 6

Answer 1

The slow bowel movement is a side effect. Opioids work on the opioid receptors which are proteins in the central nervous system. They essentially stop your nerves from sending pain signals to the brain.