Applying your knowledge quiz on Omeprazole — Transcript

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1. 0:05in our review of pharmacokinetics just
2. 0:07now we left you with two questions so
3. 0:10let's attempt to answer those questions
4. 0:12right now
5. 0:14we said that 20 of the Omeprazole gets
6. 0:18excreted in the theses
7. 0:20but how does that occur doesn't the drug
8. 0:23go into the liver to be metabolized and
9. 0:26then it comes back out into the blood as
10. 0:29a more water-soluble drug
11. 0:32well in the liver when the Omeprazole or
12. 0:35any drug for that matter goes into the
13. 0:38liver cells or hepatocytes most of that
14. 0:41does come back out into the blood as a
15. 0:44more water-soluble substance
16. 0:47but some fat soluble substances are
17. 0:50shunted out into this structure right
18. 0:53here which is called a bile canaliculus
19. 0:58the plural of a canaliculus is
20. 1:01canaliculi and the word canaliculus
21. 1:05simply means a microscopic Channel
22. 1:09a good portion of the drug that enters
23. 1:13this canaliculus is going to be excreted
24. 1:16in the feces
25. 1:18and that also explains where some of the
26. 1:2140 percent of the drug went to remember
27. 1:23that the bioavailability of Omeprazole
28. 1:27was 60 percent meaning that 60 percent
29. 1:30of the Omeprazole got into systemic
30. 1:33circulation unchanged but that leaves 40
31. 1:37percent that didn't reach systemic
32. 1:40circulation well about half of that was
33. 1:43excreted by this route here before it
34. 1:47even had a chance to circulate in the
35. 1:49system or act on its respective
36. 1:51receptors
37. 1:53so if you have that pictured in your
38. 1:55mind I would also like you to recall
39. 1:58that I asked you to think of a reason
40. 2:00why Omeprazole only needed to be taken
41. 2:03on a daily dose especially given the
42. 2:06fact that it has a half-life of just one
43. 2:09hour did you come up with a theory
44. 2:13if you know a bit about different
45. 2:15preparations of drugs you may have
46. 2:18hypothesized that Omeprazole is supplied
47. 2:21in a modified release or sustained
48. 2:23release type of preparation and that
49. 2:26would be a good theory because those
50. 2:28types of medications can be made to
51. 2:31slowly release over a period of time but
52. 2:35it's not the correct answer in this case
53. 2:39Omeprazole is not supplied in a
54. 2:43sustained release preparation
55. 2:45the correct reason that Omeprazole lasts
56. 2:49a lot longer than the half-life would
57. 2:51predict is that Omeprazole is an
58. 2:54irreversible inhibitor of the hydrogen
59. 2:56potassium atpase enzyme that secretes
60. 3:00hydrogen ions into the stomach
61. 3:02as such it takes a lot longer than one
62. 3:06would predict from that half-life of the
63. 3:09drug we will provide more information
64. 3:11about that in the course of this chapter
65. 3:14but right now we're going to learn quite
66. 3:16a bit more about enzymatic Inhibitors in
67. 3:20general