Antihypertensives

Question 1

Goal of Anti-hypertensives?

Answer 1

•The goal of antihypertensive therapy is to:
→ reduce cardiovascular & renal morbidity &mortality

•Most antihypertensive drugs lower blood pressure by reducing cardiac output (amount of blood pumped by the heart per minute) and/or decreasing peripheral resistance (resistanceof the arteries to blood flow)

Question 2

Types of Anti-hypertensives

Answer 2

1. Diuretics
2. Beta blockers
3. Alpha Blockers
4. ACE inhibitors
5. Angiotensin II Receptor Antagonists
6. Renin inhibitors
7. Ca2+channel blockers

Question 3

Mechanism of Action for Thiazide and related diuretics / Low ceiling diuretics

Answer 3

• Thiazides inhibit re absorption of Na+ and Cl- in the distal convoluted tubule of the kidney
• They increase excretion of water & Na+ and Cl-
• Thus decreases the intravascular volume, decreased cardiac output, renal blood flow & the preload

Question 4

Side effects of Thiazide and related diuretics / Low ceiling diuretics

Answer 4

• Electrolyte imbalances: Hypokalaemia, hyponatraemia, hypomagnesaemia, hypercalcaemia, hypochloraemia
• Metabolic: hyperuricaemia, hyperlipidaemia, hyperglycaemia
• Weakness, fatigue, paresthesia, impotence
• Orthostatic hypotension
• Allergic reactions

Question 5

Loop diuretics / High-ceiling diuretics

Answer 5

Furosemide

Question 6

Mechanism of action

for Loop diuretics / High-ceiling diuretics

Answer 6

• Inhibit the Na+/K+/Cl- co-transport of the luminal membrane in the ascending limb of the loop of Henle
• As such the re-absorption of Na+, K+ and Cl- is decreased.
• It decreases the intravascular volume, renal vascular resistance & preload but increase renal blood flow.

Question 7

SIDE EFFECTS of Loop diuretics / High-ceiling diuretics

Answer 7

• Electrolyte imbalances: Hypokalaemia, hyponatraemia, hypomagnesaemia, hypocalcaemia, hypochloraemia
• Metabolic: hyperglycaemia, hyperuricaemia, hypercholesterolaemia
• Hearing loss, tinnitus, vertigo (high doses IV)
• Fatigue, weakness, anorexia, abdominal pain
• Itching, Steven-Johnson syndrome, allergy
• Hypotension, dehydration

Question 8

Potassium-sparing diuretics (Spironolactone)

Answer 8

• These agents are competitive antagonists of aldosterone

* They block the aldosterone receptors & water &sodium is excreted.

Question 9

SIDE EFFECT of Potassium-sparing diuretics

Answer 9

• Hyperkalaemia
• Nausea, anorexia, abdominal pain
• Headache, weakness, dizziness
• Hormonal: anti-androgenic:
• Gynecomastia, menstrual irregularities, impotence, decreased libido