Understanding enzymatic inhibitors Part 2 — Transcript

Full transcript

1. 0:02at this time I'd like to further your
2. 0:06understanding of enzymatic Inhibitors
3. 0:09and then I'm going to apply that
4. 0:11information to the specific enzymatic
5. 0:14Inhibitors that we're talking about the
6. 0:16proton pump inhibitors
7. 0:18as I was saying sometimes our
8. 0:20medications do the intended action they
9. 0:24act on for instance an enzyme but that
10. 0:28enzyme is used to do something else that
11. 0:31we don't want to affect
12. 0:34a very common example of that is found
13. 0:37with the non-steroidal anti-inflammatory
14. 0:41drugs or aspirin or the
15. 0:44NSAIDs all of those they actually affect
16. 0:48an enzyme called cyclo oxygenase
17. 0:53cycloxygenase is an enzyme that's
18. 0:55abbreviated as Cox Cox
19. 0:59and it is great because Cox the enzyme
20. 1:04is used in the inflammatory Cascade and
21. 1:07if we can block that enzyme then we're
22. 1:11going to decrease inflammation so great
23. 1:13that's perfect isn't it well it's not so
24. 1:17perfect because of the fact that that
25. 1:20enzyme the Cox enzyme is also used in
26. 1:24other roles it's got
27. 1:26a fair few roles but two major roles are
28. 1:31having to do with protective roles in
29. 1:33both the stomach and also in the kidneys
30. 1:37and that's where the side effects come
31. 1:41the side effects of non-steroidal
32. 1:44anti-inflammatory drugs and also in
33. 1:47Aspirin have to do with the potential of
34. 1:52stomach ulcers because we don't have a
35. 1:55lot of that protection that the Cox
36. 1:57enzyme was giving and also in kidney
37. 2:01damage because once again we don't have
38. 2:04the protection that the Cox enzyme was
39. 2:07giving now those examples are especially
40. 2:10prevalent in people who take the Cox
41. 2:15inhibitors or in other words aspirin or
42. 2:17non-steroid anti-inflammatory drugs when
43. 2:20they take those for a long period of
44. 2:22time
45. 2:23and once again as I've said before it's
46. 2:26not an issue for
47. 2:29Omeprazole and the proton pump
48. 2:31inhibitors because the enzyme that we're
49. 2:33talking about is almost specific to the
50. 2:37parietal cells so we don't have to worry
51. 2:39about that but there is another issue
52. 2:42with enzymes that's relevant to the
53. 2:45proton pump inhibitors
54. 2:48we mentioned that in some cases
55. 2:50medications may actually have a
56. 2:53molecular structure that can bind to for
57. 2:56instance another enzyme or another
58. 2:59receptor I think we've talked about it
59. 3:01with respect to another receptor but now
60. 3:04we're talking about it with respect to
61. 3:06binding to another enzyme an enzyme that
62. 3:10it's not supposed to bind to in other
63. 3:13words there are medications that have
64. 3:16crossover effects they may have a little
65. 3:19bit of a binding to another enzyme and
66. 3:23some not all of the proton pump
67. 3:25inhibitors but some of the proton pump
68. 3:28inhibitors have that crossover effect
69. 3:32Omeprazole can have a slight binding to
70. 3:35some of the liver enzymes
71. 3:38remember that the liver enzymes are made
72. 3:42to metabolize drugs and when we read
73. 3:45about
74. 3:46Omeprazole in a drug manual the manual
75. 3:49is going to say that the Omeprazole
76. 3:53inhibits
77. 3:54c y p 2 c 1 9 and cyp
78. 4:022 C 8. so both of those are inhibited by
79. 4:08Omeprazole what does that mean
80. 4:11well when you hear about a medication
81. 4:13that affects the liver enzymes
82. 4:15abbreviated as cyp something something
83. 4:19something at least three more letters
84. 4:21and numbers after the cyp basically just
85. 4:25means that you need to be careful about
86. 4:27combining that medication with other
87. 4:30medications
88. 4:32that's really easy you don't have to
89. 4:34memorize the exact enzymes that every
90. 4:37drug affects you simply look at your
91. 4:40drug monograph drug manual or the
92. 4:43reference manual that you're using and
93. 4:45you check which specific drugs are going
94. 4:48to be affected
95. 4:50but it's important to note that the
96. 4:52effects can be very variable
97. 4:55in some instances there might be hardly
98. 4:57any effect in other instances
99. 5:00Omeprazole may actually increase the
100. 5:03effects of another drug and in other
101. 5:07instances for instance Omeprazole may
102. 5:09actually decrease the effects of another
103. 5:12drug
104. 5:13once again that'll always be in your
105. 5:16drug manuals so you don't have to
106. 5:19memorize that type of information
107. 5:23this kind of effect is very common in
108. 5:26many medications and even in a lot of
109. 5:29different foods so a lot of different
110. 5:32foods can affect liver enzymes that
111. 5:35metabolize drugs for instance grapefruit
112. 5:38juice is one of the biggest concerns
113. 5:41it's a very strong inhibitor of
114. 5:44cytochrome
115. 5:46p450 cyp3a4
116. 5:51and that particular enzyme is involved
117. 5:55in metabolizing over 50 percent of the
118. 5:58medications that we have on the market
119. 6:00today
120. 6:01the effects of grapefruit juice can be
121. 6:04so substantial that even a small amounts
122. 6:08a small 200 mil glass of grapefruit
123. 6:12juice or one fruit could have
124. 6:16significant effects and actually results
125. 6:19in drug toxicity and furthermore the
126. 6:23effect doesn't necessarily mean that
127. 6:25it's going to decrease the action or
128. 6:27increase the action sometimes that
129. 6:29effect is different for different drugs
130. 6:36we just said that by inhibiting the same
131. 6:39enzyme in the liver the effect can be
132. 6:42different for different drugs for
133. 6:44instance grapefruit juice inhibits
134. 6:47cyp3a4 and makes some drugs less active
135. 6:51and Other Drugs more active how can it
136. 6:54affect two different medications so
137. 6:57differently
138. 6:58well the enzyme may change drug a from a
139. 7:01pro drug to an active drug when
140. 7:04grapefruit juice inhibits the enzyme in
141. 7:07that case the pro drug would remain
142. 7:09inactive
143. 7:11conversely the enzyme may change drug B
144. 7:15from a highly active drug to an inactive
145. 7:19drug inhibition of the enzyme in that
146. 7:22case will allow more highly active drug
147. 7:25to remain in the system for longer
148. 7:28the other thing to remember about drugs
149. 7:31and enzymes is that some drugs are
150. 7:33inducers of certain liver enzymes and
151. 7:37when a drug is an inducer of a liver
152. 7:40enzyme it basically goes over to the
153. 7:43liver cells and instructs the cell to up
154. 7:45regulate the production of an enzyme
155. 7:50remember we make our proteins with the
156. 7:53DNA in the nucleus of the cell
157. 7:57well a drug that acts as an inducer of
158. 8:01an enzyme is basically instructing the
159. 8:03cell to increase the production of that
160. 8:06enzyme but once again as we apply that
161. 8:10to our medications your drug manuals
162. 8:13will have all of the various reactions
163. 8:15that are possible and it's not something
164. 8:17that you really need to memorize at all