Lecture 15 (Quiz 3)

Question 1

When selecting an Antihypertensive, what 4 things should be taken into account?

Answer 1

• Underlying Medical Conditions
• Race (Avoid ACE-Inhibitors in black individuals)
• Severity (Vasodilators are very potent)
• Combinations are common

Question 2

There are 4 classes of Antihypertensives (Diuretics, Sympathoplegics, Direct Vasodilators and Anti-Angiotensin Agents), what makes all of these different and what are examples of each?

Answer 2

• Diuretics: Depletes sodium which reduces blood volume, and drops TPR. Causes an increase in urine levels. (Osmotic Agents [Mannitol], Carbonic Anhydrase Inhibitors [Acetazolamide], Loop Diuretics [Furosemide and Bumetanide], Thiazides [Hydrochorothiazide and Chlorthalindone], Potassium-Sparing [Spironoalctone and Amiloride])
• Sympathoplegics: Reduce peripheral vascular resistance and inhibits cardiac function which decreases TPR. (Sympathetic Alpha and Beta drugs that decrease TPR, could be agonists or antagonists)
• Direct Vasodilators: Relax vascular smooth muscle which dilates resistance vessels (decreases TPR), and increases capacitance. (Hydralazine, Verapamil, Diltiazem, Nifedipine, Minoxidil)
• Anti-Angiotensin Agents: Inhibit the action and production of Angiotensin which reduces peripheral vascular resistance and sometimes blood volume. (ACE-Inhibitors [Captopril], Angiotensin Inhibitors [Losartan])

Question 3

Diuretics effect different parts of the Kidney. Which part does Osmotic Agents (Mannitol) effect? Carbonic Anhydrase Inhibitors (Acetazolamide)? Loop Diuretics (Furosemide and Bumetanide)? Thiazides (Hydrochorothiazide and Chlorthalindone)? Potassium Sparing (Spironolactone and Amiloride)?

Answer 3

• Osmotic: Thin Descending Limb
• Carbonic Anhydrase Inhibitors: Proximal Convoluted Tubule.
• Loop Diuretics: Thick Ascending Limb
• Thiazides: Distal Convoluted Tubule
• Potassium Sparing: Collecting Tubule

Question 4

What are the drugs and effects of Osmotic Agents in Diuretics?

Answer 4

• Mannitol

- Water is retained (increased urination), NOT used for Hypertension, but used for head trauma pressure.

Question 5

What are the drugs and effects of Carbonic Anhydrase Inhibitors in Diuretics?

Answer 5

• Acetazolamide
• Shuts down reabsorption of H2CO3 into the interstitial space, which causes less sodium reabsorption, and more sodium in the lumen. Not used for hypertension, but as a diuretic for glaucoma.

Question 6

What are the drugs and effects of Loop Diuretics?

Answer 6

• Furosemide and Bumetanide
• Inhibit luminal sodium/potassium/ chlorine transporters in thick ascending limb. Can cause Hypokalemia??? Very efficacious! Inhibited by NSAIDs in certain conditions.

Question 7

What are the drugs and effects of Thiazides in Diuretics?

Answer 7

• Hydrochlorothiazide and Chlorthalindone
• Inhibit NaCl reabsorption by blocking the Na/Cl transporter. Can cause Hypokalemia??? Inhibited by NSAIDs in certain conditions.

Question 8

What are the drugs and effects of Potassium Sparing in Diuretics?

Answer 8

• Spironolactone and Amiloride
• Prevent Potassium secretion by antagonizing Aldosterone (Spiro), or Sodium influx through ion channels (Amil). Often used in combination with loop diuretics to offset hypokalemia and NOT used with ACE-Inhibitors due to hyperkalemia.

Question 9

What are the drugs and effects of ACE-Inhibitors in Anti-Angiotensin Agents?

Answer 9

• Captopril
• Inhibit Peptidyl Dipeptidase (converting enzyme) from Angiotensin I to Angiotensin II. Increases Bradykinin levels which acts as a Vasodilator. Can cause Dry Cough due to increased Bradykinin and Hyperkalemia due to little Aldosterone.

Question 10

What are the drugs and effects of Angiotensin II Inhibitors in Anti-Angiotensin Agents?

Answer 10

• Losartan
• Decrease peripheral vascular resistance. More selective blockers of Angiotensin than ACE-Inhibitors. Same side effects of ACE-Inhibitors but less Dry Cough.

Question 11

Direct vasodilators do cause vasodilation through many means. Which direct vasodilator releases nitric oxide from a drug or endothelium? Which one causes a reduction of calcium influx and can cause gingival hyperplasia? Which one causes the Hyperpolarization of the smooth muscle membrane through opening of potassium channels? These are all mediated by what?

Answer 11

• Hydralazine
• Verapamil, Diltiazem, and Nifedipine.
• Minoxidil
• Baroreceptors and the Sympathetic Nervous System.

Question 12

The Sympathoplegics do what?

Answer 12

• Act on the Alpha/Beta-Agonists/Antagonists that decrease TPR *(may want to review)