Anti-hypertensive Drugs

Question 1

Hypertension is defined as:

Answer 1

BP>140/90 mmHg

Question 2

Etiology of hypertension:

Answer 2

90% idiopathic, primary (udk the causes)
10% by specific cause, narrowing of artery, secondary

Question 3

What are some complications of hypertension?

Answer 3

1. Congestive heart failure
2. Ischemia
3. Myocardial infarction
4. Renal damage
5. Cerebrovascular accidents (stroke)

Question 4

Name some anti-hypertensive drugs:

Answer 4

1. Diuretics
2. β-blocker e.g. propranolol
3. ACE inhibitors
4. Calcium channel blockers

Question 5

Name some diuretics.

Answer 5

1. Thiazides
2. Loop diuretics

Question 6

What is the difference between thiazides and loop diuretics

Answer 6

Thiazides decrease the urinary excretion of calcium, while loop-diuretics have the opposite effect.

Question 7

How do loop diuretics work?

Answer 7

Loop diuretics work to lower the fluid buildup in the body by reducing sodium reabsorption in the loop of Henle, thereby causing the elimination of water and sodium from the body.

• acts at TAL (thick ascending limb)
• more potent than thiazide, often used for chronic renal/heart failure

Question 8

How do thiazides work?
(Mechanism of action)

Answer 8

1. Inhibit NaCl reabsorption by blocking Na+/Cl- transporter at DCT=> decreases blood volume & bp
2. Enhance Ca2+ reabsorption at DCT
3. Enhances urea reabsorption & inhibit excretion at PCT => diurtetic-induced hyperuricemia (predisposes for gout)
   - action depends on renal PG synthesis (NSAIDs decrease PG synthesis, interfere w thiazides action)

Question 9

Diuretics are used to treat:

Answer 9

1. Hypertension
2. Congestive heart failure

Question 10

Adverse effects of thiazides:

Answer 10

1. Hypokalemia
2. Hyponatremia
3. Hyperglycemia
4. Hyperlipidemia
5. Hyperuricemia
6. Hypercalcemia

+ contraindicated in gout & diabetes

Question 11

Name some β-blockers.

Answer 11

1. Propranolol (non-selective)
2. Atenolol (β1-selective)

Question 12

Mechanism of action of β blockers:

Answer 12

Decreased heart rate & force, decreased BP

Question 13

β blockers used to treat:

Answer 13

1. Hypertension
2. Angina (heart pain)
3. Following myocardial infarction

Question 14

What are some adverse effects of β blockers?

Answer 14

1. Bradycardia
2. Bronchospasm
   - cuz propranolol is non-selective, it blocks β2 adrenoceptors
3. Sedation/vivid dream

+ contraindicated in those w asthma

Question 15

What are some contraindications for β blockers?

Answer 15

1. Hypoglycemia
   - β blockers will mask signs of hypoglycemia e.g. increased heart rate
2. Bradycardia
3. Asthma (esp non-selective β blockers, propranolol)
4. Diabetes

Question 16

Name some ACE inhibitors (angiotensin converting enzyme inhibitors)

Answer 16

Lisinopril, Enalapril, Captopril

Question 17

Mechanism of ACE inhibitors?

Answer 17

1. Decrease in ANG II by blocking conversion form ANG I
   - decrease in vasoconstriction => decrease in peripheral vascular resistance => decrease bp
   - decreased aldosterone => decrease Na+ & H2O retention => decreased blood vol => decreased bp
2. Increased bradykinin by preventing breakdown => decreased PG & NO => increased vasodilation => decreased bp

Question 18

Uses of ACE inhibitors:

Answer 18

1. Hypertenison
2. Cardiac failure
3. Following myocardial infarction

Question 19

What are some adverse effects of ACE inhibitors:

Answer 19

1. Severe hypotension
2. Hyperkalemia: decreased aldosterone => decreased K+ excretion
3. Angioedema: bradykinin causes vasodilation & increased permeability
4. Dry cough: accumulation of bradykinin
5. Acute renal failure

+ contraindicated in pregnancy, esp in eclampsia (fetal renal damage)