Loperamide — Transcript

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1. 0:00throughout this chapter we've learned
2. 0:02quite a bit about the cellular receptors
3. 0:04by using the medications from the drug
4. 0:06class termed opioids we've also learned
5. 0:10the most important safety issues
6. 0:12regarding the treatment of diarrhea
7. 0:15right now we're going to finalize the
8. 0:18chapter with a few last points about the
9. 0:20specific opioid termed loperamide
10. 0:22starting with the mechanism by which it
11. 0:25works in the gastrointestinal tract we
12. 0:28have the nervous system cells and they
13. 0:31communicate with the brain and they also
14. 0:34have an effect on what's happening in
15. 0:36the git this very large network of
16. 0:39nerves is called the enteric nervous
17. 0:41system and it can speed up or slow down
18. 0:44the peristaltic actions in the GLT and
19. 0:47it can also affect the secretion of
20. 0:50products such as mucus into the git
21. 0:54peristaltic actions are wave-like
22. 0:57muscular contractions of the muscles in
23. 1:00the git
24. 1:02also in the git we have opioid receptors
25. 1:05in the cells and when our body's natural
26. 1:08opioids bind to those opioid receptors
27. 1:11there's a decrease in peristaltic
28. 1:14actions within the git and you can see
29. 1:18from that the endogenous opioids are one
30. 1:20of the tools in which we regulate the
31. 1:24gastrointestinal tract in the presence
32. 1:26of endogenous opioids the peristaltic
33. 1:30actions will decrease and that will
34. 1:34allow more time for the absorption of
35. 1:38fluids from the git so the fecal
36. 1:42contents get drier
37. 1:45so loperamide is an opioid Agonist that
38. 1:49acts on those same receptors as the
39. 1:52natural endogenous opioids that slows
40. 1:55down the git and as such relieves
41. 1:58diarrhea
42. 1:59remember that we're taking a
43. 2:02pharmacological dose of the agent so it
44. 2:05has much more of a profound action than
45. 2:08our natural release of opioids would
46. 2:12to be clear loperamide is not the only
47. 2:15medication for diarrhea most of our
48. 2:18opioid medications will decrease
49. 2:20diarrhea and there's also other
50. 2:22medications known as
51. 2:24anticolinergic agents so against
52. 2:28acetylcholine that are useful for
53. 2:30diarrhea as well but loperamide is
54. 2:33normally the preferred medication
55. 2:35because most of it stays in the
56. 2:38gastrointestinal tract and simply Works
57. 2:41locally
58. 2:45right now I'd like you to try to
59. 2:48hypothesize about what an opioid
60. 2:50antagonist would do and what its
61. 2:54applications would be
62. 2:56why would we want to block the opioid
63. 2:59receptors in the git and why would we
64. 3:02want to block the opioid receptors in
65. 3:04other parts of the body
66. 3:09and you're right if you had said to
67. 3:12reverse the effects of too many opioids
68. 3:16in the body
69. 3:17we have a couple different kinds of
70. 3:20opioid antagonists one is called methyl
71. 3:24Naltrexone
72. 3:26methanaltrexone is an opioid receptor
73. 3:28antagonist that has a very poor capacity
74. 3:31to be absorbed so you can think of it as
75. 3:34being pretty much the exact opposite of
76. 3:36loperamide
77. 3:38and it's specifically given to decrease
78. 3:41the constipating effects of the opioids
79. 3:45we don't give it for any kind of
80. 3:47constipation but rather for instance if
81. 3:50a person has taken high doses of opioid
82. 3:53medications for cancer pain The
83. 3:56Physician may need to block some of
84. 3:58those receptors in the git so the person
85. 4:01is relieved of their severe constipation
86. 4:05and another opioid antagonist is
87. 4:09naloxone naloxone is an opioid
88. 4:12antagonist that's used for people who
89. 4:14are experiencing the opioid related
90. 4:16respiratory depression that comes along
91. 4:19with overdose of opioids
92. 4:22naloxone binds so strongly to the opioid
93. 4:26receptors that it actually knocks off
94. 4:28other opioids that are already there and
95. 4:31quickly reverses the life-threatening
96. 4:33side effects of opioid overdose the
97. 4:36important thing about naloxone is that
98. 4:38it is extremely short-lived in the body
99. 4:41or in other words it has a very short
100. 4:44half-life
101. 4:46and it needs to be re-administered a
102. 4:49couple times before the other opioids
103. 4:51will be out of the system