Anti hypertensives

Question 1

List the main drug classes of antihypertensives

Answer 1

1. ACE inhibitors
2. Angiotensin receptor blockers
3. Beta blockers
4. Calcium channel blockers (dihydropyridines)
5. Diuretics

Question 2

Describe the effect of ACE inhibitors

Answer 2

Inhibit the enzyme
=> prevent conversion of angiotensin 1 to 2.

Angiotensin II normally causes blood vessels to constrict, leading to an increase in blood pressure.
=> ACE inhibitors allow for vasodilation

By blocking angiotensin II, ACE inhibitors decrease aldosterone production, reducing fluid retention and lowering blood pressure.

Question 3

List at least 2 ACE inhibitors

Answer 3

Lisinopril, Captopril, Enalapril

Question 4

List at least 2 adverse effects of ACE inhibitors and in which group of patients are they contraindicated in.

Answer 4

Contraindicated in PREGNANCY

Adverse effects:
1. severe hypotension
2. acute renal failure
3. dry cough

Question 5

List at least 2 Angiotension 2 type 1 blockers (AT1 blockers)

Answer 5

Valsartan, losartan, candesartan

Question 6

What is the MOA of AT1 blockers?

Answer 6

Antagonist to AT1 receptors and hence Angiotension 2 cannot exert its effect

Question 7

Main adverse effect of AT1 blockers and its contraindication

Answer 7

NO IN PREGNANCY

Less or no dry cough

Question 8

List 3 beta 1 selective blockers

Answer 8

Atenolol
Bisoprolol
Metoprolol succinate

Question 9

List a non selective beta blocker

Answer 9

Propranolol

Question 10

Briefly explain why ACEi causes dry cough

Answer 10

ACE inactivates bradykinins.

When it is inhibited, bradykinin levels increases which causes the dry hacking cough.

Question 11

List the 3 classes of drugs that are used as second line for hypertension

Answer 11

1. Hydralazine
2. Mineralocorticoid receptor antagonists
3. Alpha-blockers

Question 12

List 2 adverse effects of beta blockers

Answer 12

1. Hypotension
2. Bradycardia
3. AV nodal block
4. Reduced exercise capacity
5. Bronchoconstriction

Question 13

What is one group of patients where beta blockers must be used with caution?

Answer 13

Asthmatic patients as beta blockers can cause bronchoconstriction

Question 14

Name a diuretic used as an anti-hypertensive

Answer 14

Thiazides:
- Hydrochlorothiazide
- Indapamide

Question 15

Describe the MOA of thiazides

Answer 15

Inhibit NaCl reabsorption by blocking the sodium-chloride symporter.

Enhance Ca2+ reabsorption

Question 16

List at least 3 adverse effects of thiazides

Answer 16

Thiazide - loop diuretic
Diuretics make you pee more
= loss of blood volume
= Loss of osmolarity
= all solutes become concentrated

1. Hypokalaemia metabolic alkalosis
2. Hyponatraemia
3. Hyperuricaemia
4. Hyperglycaemia
5. Hyperlipidaemia
6. Hypercalcaemia

** Hint: Since in renal we learnt that most of the reabsorption relies on the sodium electrochemical gradient and cotransport channels, if sodium reabsorption is inhibited, all these other substances don’t get reabsorbed either.

Question 17

Name 2 alpha adrenergic antagonist

Answer 17

Prazosin
Alfuzosin
Terazosin

Question 18

Describe the MOA of alpha adrenergic antagonists

Answer 18

Target alpha 1 adrenergic receptors on vascular smooth muscles that mediate vasoconstriction.

Antagonist prevents activation of alpha adrenergic receptors and hence keep the vessel tone lower

This reduces peripheral vascular resistance and hence lower BP.

Question 19

Which drug can treat both hypertension and benign prostate hyperplasia?

Answer 19

Prazosin

Question 20

What type of diuretics are likely to lead to hyperuricaemia and precipitate a gout attack?

Answer 20

Thiazide diuretics

Eg. Chlorothiazide

Question 21

Which group of diuretic agents act preferentially on the collecting duct of the nephron?

Answer 21

ADH antagonists

Question 22

What is the MOA of loop diuretics?

Answer 22

Inhibit the sodium-potassium-chloride cotransporter (NKCC2) in the thick ascending limb of the loop of Henle.

Question 23

List at least 2 loop diuretics

Answer 23

Furosemide
Bumetanide
Torsemide

Question 24

Which part of the nephron does loop diuretics act on?

Answer 24

Thick ascending limb of Loop of Henle

Question 25

What is the MOA of thiazide diuretics?

Answer 25

Inhibits the Na/Cl co transporter in the DCT and hence block their reabsorption.

Question 26

List a thiazide diuretic

Answer 26

Chlorothiazide, chlorthalidone

Question 27

Which part of the nephron do thiazide diuretics act on?

Answer 27

DCT

Question 28

List at least 2 potassium sparring diuretics

Answer 28

Spironolactone (aldosterone antagonist)

Amiloride (sodium channel blocker)

Question 29

What is the MOA of spironolactone?

Answer 29

Aldosterone antagonist that acts on its receptors at the distal tubules and collecting duct.

Inhibit aldosterone from exerting its effects

Decrease Na reabsorption and K excretion.

Question 30

What is the MOA of amiloride?

Answer 30

Potassium sparing diuretic

Act on the DCT and block sodium transport, thereby inhibiting sodium-potassiume exchange

Question 31

Which part of the nephron does potassium sparing diuretics act on?

Answer 31

Collecting duct and DCT

Question 32

What is the mechanism of action of ADH antagonist?

Answer 32

Block ADH from binding the vasopressin receptors and hence cannot exert its effect

Question 33

What is the MOA of carbonic anhydrase inhibitors?

Answer 33

Inhibit the enzyme carbonic anhydrase in the PCT

Hence blocks the conversion of carbonic acid to bicarbonate and hydrogen ions.

This thus increase urinary excretion of bicarbonate, sodium and water.

Question 34

What is the clinical indication for a carbonic anhydrase inhibitor?

Answer 34

Metabolic alkalosis