Lecture 5: Pharmacology of the Medicines used in treating hypertnsion Flashcards
(42 cards)
What is the goal of treating hypertension?
To achieve and maintain systolic blood pressure below 140 mmHg and diastolic blood pressure 90 mmHg
What is the first line of treatment for hypertension?
Lifestyle modifications
What are the lifestyle modifications required for the treatment of hypertension?
- Weight reduction
- Regular physical exercise
- DASH eating plan (lots of fruit and veg, little meat)
- Reduction of dietry sodium intake
- Moderation of alcohol intake
What are the pharmacological treatments for hypertension?
- Diuretics
- Sympatholytics
- Calcium channel blockers
- Direct acting vasodilators
How do diuretics work?
Indirectly prevent the reabsorption of water in the kidneys, most of them by preventing the reabsorption of sodium
What do ACE inhibitors lead to?
- less angiotensin II
- more bradykinin
What is first line treatment for hypertension?
ACE inhibitor
Where do diuretics have their effect?
Collecting duct
What are the different classes of diuretics?
- Loop diuretics
- Thiazides
- Potassium sparing diuretics
Name loop diuretics
Furosemide supplemented with spironolactone or amiloride
Where is the sight of action of furosemide?
Proximal convolated tubule
Where is the sight of action of thiazides?
Early distal convoluted tubule
Where is the sight of action of potassium sparing?
Tubule and collecting duct - distal nephron
What is the mechanism of action of diuretics?
Loop diuretics act principally by inhibiting the Na/K/2Cl co-transporter
What is a major problem with loop diurectics?
Hypokalaemia
What are the most commonly used diurects?
Thiazide
How do thiazide diuretics work?
Inhibit the sodium-chloride transporter in the distal tubule
What drugs act on RAAS?
Angiotensin converting enzyme:
- Captotril
- Enalapril
- Lisinopril
- Other ACE inhibitors
Angiotensin II receptors
- Losartan
- Valsartan
- Other ARBs
What inhibits renin production?
- B1 antagonists
- Aliskiren - not recommended for use
What do ACE inhibitors have thier effect on?
Lung
Give examples of ACE inhibitors (3)
- Catopril
- Lisinopril
- Enalapril
What does a decrease in angiotensin II result in?
- Vasodilation
- Decreased blood volume
- Decreased cardiac and vascular remodelling
- Potassium retention
- Fetal injury
What does an increase in bradykinin result in?
- Vasodilation
- Cough
- Angioedema (rare)
How do ACE inhibitors work?
Block the action of the ACE, to prevent the conversion of angiotensin I to angiotensin II
- Reduces peripheral vascular resistance (afterload), so lowers blood pressure
- Dilates the efferent glomerular arteriole, which reduces intra-glomerular pressure
- Reduces aldosterone levels which promotes sodium and water excretion, helps reduce preload