Free_Man**
Bluelighter
- Joined
- Oct 5, 2009
- Messages
- 684
Loperamide is an opioid-receptor agonist and acts on the μ-opioid receptors in **the myenteric plexus **large intestines**; **by itself it does not affect the central nervous system like other opioids.**
It works by decreasing the activity of the myenteric plexus, which, like morphine, decreases the tone of the longitudinal smooth muscles but increases tone of circular smooth muscles (anal sphincter) of the intestinal wall. This increases the amount of time substances stay in the intestine, allowing for more water to be absorbed out of the fecal matter. Loperamide also decreases colonic mass movements and suppresses the gastrocolic reflex.[4]
Loperamide molecules do not cross the blood-brain barrier in significant amounts, and, thus, it has no analgesic or euphoric properties. Any that do cross the blood-brain barrier are quickly exported from the brain by P-glycoprotein (Pgp), also known as multidrug resistance protein (MDR1). Tolerance in response to long-term use has not been reported.
However, loperamide has been shown to cause a mild physical dependence during preclinical studies, specifically in mice, rats, and rhesus monkeys. **Symptoms of mild opiate withdrawal have been specifically following abrupt discontinuation of long-term therapy with loperamide.[5][6]**
interesting what wikipedia has to say .... .... seems like loperamide is addictive ... if its addictive SOME of it must cross the bbb......