Lecture 10 Cardio Pharmacology Part II

Question 1

*Understand the role of the kidneys in the treatment of CHF.

What is the role of the Kidneys?

Answer 1

Primary role is regulation of the extracellular fluid (plasma and interstitial fluid) environment in the body.

This is accomplished through the formation of urine, which is a modified filtrate of the blood plasma. In the process of urine formation, the kidneys regulate:

• The volume of blood.
• The concentration of waste products in the blood.
• The concentration of electrolytes (including Na+, K+) in the plasma.
• The pH of the plasma - regulated

Question 2

Function of Diuretics?

Answer 2

Drugs that act on the kidney to increase urine flow.
Most work by reducing the reabsorption of electrolytes by the kidney tubules.

The increased electrolyte excretion is accompanied by an increase in water excretion, necessary to maintain an osmotic balance.

Although widely used in the treatment of hypertension, diuretics are also used to reduce oedema in a number of disease states including renal disease, hepatic cirrhosis and congestive heart failure

Question 3

*List the three classes of anti-anginal drugs.

Answer 3

The organic nitrates
Calcium channel blockers
b blockers

Question 4

*List with examples the calcium channel blockers used to treat angina.

Answer 4

Amlodipine besylate
Diltiazem
Nifedipine

Question 5

*Outline the mode of action of the calcium channel blockers used to treat angina.

Answer 5

Inhibit the entry of calcium into cardiac and smooth muscle cells of the coronary and systemic arterial beds.
This results in vasodilatation causing a decrease in smooth muscle tone and vascular resistance.

Question 6

*List with examples the beta blockers used to treat angina.

Answer 6

Propranolol
Metoprolol
Atenolol

Question 7

*Outline the mode of action of the beta blockers used to treat angina.

Answer 7

Suppress the activation of the heart by blocking the b1 adrenoceptor receptor subtype.
They also reduce cardiac output and blood pressure.
Beta blockers reduce the frequency and severity of angina attacks and are useful in patients with myocardial infarction.

Beta blockers are contraindicated in patients with diabetes(because it blocks the effect of insulin), peripheral vascular disease or chronic obstructive pulmonary disease (COPD)=> because they take B agonists as Tx

Question 8

*Define what is meant by hypertension

Answer 8

Elevation of arterial blood pressure above an arbitrarily defined normal value. Know normal values

Question 9

*Distinguish between primary and secondary hypertension

Answer 9

PRIMARY (essential, idiopathic) hypertension 
Cause has not been identified
Family history (genetic predisposition)
Theories include:
1. insulin resistance
2. reduced NO production
3. increased sympathetic activity
4. abnormal reactivity of blood vessels
5. renal abnormalities
6. multifactorial

SECONDARY HYPERTENSION
Cause can be identified.
May be possible to correct the underlying abnormality
5-10% of total presentations - 3 main types
1. Renal dysfunction
2. Endocrine (including adrenal tumours-secrete things that ^ BP)
3. Drug induced (adverse effects)

Question 10

*Outline the non-pharmacological treatments for hypertension

Answer 10

1. Stopping SMOKING
2. Reduced ALCOHOL intake
   Reducing intake from 452 to 64ml -Mean decrease in 5 mmHg systolic pressure and 3 mmHg diastolic pressure.
3. WEIGHT reduction
   On average a decrease of 1 kg body weight is associated with 1% decrease in systolic and diastolic pressures
4. SALT restriction
   Reduction of salt intake by one-third results in reduction in systolic BP by 4.9 ± 1.4 mm Hg and in diastolic BP by 2.6±0.8 mm Hg.
5. Increased POTASSIUM intake
   Oral potassium supplements have been shown to decrease systolic BP by 8.2 mm Hg and lower diastolic BP by 4.5 mm Hg.
6. PHYSICAL ACTIVITY
   Patients with low levels of physical activity were 50% more likely to develop clinical hypertension than those with high levels of physical activity

Question 11

*Describe the rationale for using angiotensin II receptor antagonists to alleviate the symptoms of hypertension and give examples of this class of drugs.

Answer 11

Activation of angiotensin II receptors results in increased aldosterone production.
 ALDOSTERONE mediates cell processes 
~ vasoconstriction of smooth muscle
~increased retention of sodium and water
~Leads to increased BP

Blockage of the angiotensin II receptors by specific antagonists inhibits aldosterone production => DECREASES BP
EXAMPLES =
Losartan
Telmisartan
Candesartan cilexetil
Irbesartan

Question 12

What pathologies can hypertension increase the risk of?

Answer 12

ATHEROSCLEROSIS – fatty deposits in the arteries => ANGINA => MI
CORONARY ARTERY DISEASE
CONGESTIVE HEART DISEASE - cardiomegaly
DIABETES
INSULIN RESISTANCE 
STROKE - haemorrhagic or occlusive (atherosclerosis/ thrombosis)
RENAL DISEASE => failure
RETINAL DISEASE