Wk 12. AntiDiuretics

Question 1

1. When should diuretics be taken?

Answer 1

In the morning if daily, morning and 2 pm if bid

Question 2

2. Where does the most reabsorption take place?

Answer 2

Proximal convoluted tubule

Question 3

3. Where is 20% of the sodium reabsorbed?

Answer 3

Ascending loop of Henle

Question 4

4. Which diuretics have the greatest potential for diuresis? Why?

Answer 4

Osmotic diuretics followed by loop diuretics.

They block sodium reabsorption at sites where more sodium is normally reabsorbed.

Question 5

5. Large dose of loop diuretics may adversely affect what organ?

Answer 5

Ear, ototoxicity

Question 6

6. What permanent adverse effect may occur with ethacrynic acid (Edecrin)?

Answer 6

Ototoxicity

Question 7

7. What change in calcium may occur with loop diuretics?

Answer 7

Hypocalcemia

Question 8

8. What class of diuretics does not cause calcium loss?

Answer 8

Thiazides

Question 9

9. What change in blood sugar may be seen with loop diuretics?

Answer 9

Hyperglycemia

Question 10

10. Thiazide diuretics are contraindicated with an allergy to what?

Answer 10

Sulfonamides

Question 11

11. When might thiazide diuretics be ineffective?

Answer 11

When the glomerular filtration rate (GFR) is below 15-20 mL/min

Question 12

12. What are some signs of electrolyte imbalance?

Answer 12

Muscle weakness, twitching, nausea and vomiting, dysrhythmias, dry mouth and thirst, confusion, etc.

Question 13

13. Loop diuretics decrease which electrolytes?

Answer 13

K+, Na+, Cl-, Ca2+, Mg2+

Question 14

14. The coadministration of digoxin (Lanoxin) and diuretics may precipitate what condition?

Answer 14

Digoxin toxicity with dysrhythmias.

Question 15

15. Potassium-sparing diuretics should not be used with which three antihypertensive drug categories? Name two common potassium-sparing diuretics.

Answer 15

ACE inhibitors, Angiotensin II receptor blockers, direct renin inhibitors.
Spironolactone (Aldactone) and triamterene (Dyrenium)

Question 16

16. Diuretics and antihypertensive drugs can cause what adverse effect?

Answer 16

Additive hypotension

Question 17

17. Why are osmotic diuretics used in renal failure?

Answer 17

To maintain urine flow through the tubule.

Question 18

18. Why are osmotic diuretics used for cerebral edema?

Answer 18

Used to reduce intracranial pressure

Question 19

19. What is added to deter patients from taking diphenoxylate (Lomotil) for analgesic effects?

Answer 19

Atropine, causes dry mouth and tachycardia.

Question 20

20. Name 2 contraindications for Diphenoxylate (Lomotil)?

Answer 20

Infectious diarrheas and pseudomembranous colitis.

Question 21

21. What are the mechanisms of action for bulk-laxatives? Where do they work?

Answer 21

Form nondigestible gel that expands with bacterial action. The enlarged fecal size triggers peristalsis. Small intestine and colon.

Question 22

22. List contraindications for laxatives. Why?

Answer 22

Abdominal pain, nausea, cramps, appendicitis, bowel obstruction, diverticulitis, ulcerative colitis, enteritis.
Worry about bowel perforation.

Question 23

23. Why must a bulk laxative be administered with a full glass of fluids?

Answer 23

To prevent bowel obstructions.

Question 24

24. What are the mechanisms of action for surfactant laxatives? Where do they work?

Answer 24

Decrease surface tension allowing water to penetrate stool, inhibit fluid absorption in gut, and increase water and electrolyte secretion into gut. Small intestine and colon.

Question 25

25. What is the difference between Docusate sodium (Colace) and Peri-Colace?

Answer 25

Peri-Colace includes a stimulant laxative, sennosides.

Question 26

26. What are the mechanisms of action for stimulant laxatives? Where do they work?

Answer 26

Increase peristalsis, inhibit fluid reabsorption in gut, and increase water and electrolyte secretion in gut. Colon.

Question 27

27. What food substance and drug category may not be taken with Bisacodyl (Dulcolax), a stimulant laxative? Why?

Answer 27

Milk and antacids. They dissolve the enteric coating meant to protect the stomach from the drug.

Question 28

28. What harmless urinary side effect is caused by senna, a stimulant laxative?

Answer 28

Yellowish-brown or pinkish urine.

Question 29

29. What are the mechanisms of action for saline laxatives? Where do they work?

Answer 29

Attracts water that stretches the gut and causes peristalsis. Small intestine and colon.

Question 30

30. What is a non-GI contraindication to magnesium hydroxide? Why?

Answer 30

Renal disease. Magnesium accumulates and causes CNC toxicity.

Question 31

31. What are the mechanisms of action for sugar laxatives? Where do they work?

Answer 31

The disaccharide is metabolized into acid by gut bacteria. The acids cause an osmotic action. Colon.

Question 32

32. Name a non-GI use for lactulose?

Answer 32

High ammonium blood levels.

Question 33

33. What are the mechanisms of action for glycerin suppositories? Where do they work?

Answer 33

Softens and lubricates stool. Stimulates rectal contraction. Rectum.

Question 34

34. What is the most important indication of constipation?

Answer 34

Hard, pellet-like feces.

Question 35

35. What is a possible effect of laxatives during pregnancy?

Answer 35

Initiation of labor.

Question 36

36. Discuss the use of laxatives during lactation.

Answer 36

The drug may be found in breast milk.