Hypertension

Question 1

What is hypertension defined as?

Answer 1

Hypertension is defined as an increase in blood pressure in the arteries.

Question 2

What are the two types of hypertension, what are the causes?

Answer 2

The two types of hypertension are primary and secondary. The reasons for primary are unknown but may be due to genetics or environmental factors. Secondary is caused by kidney or endocrine diseases.

Question 3

Hypertension itself is asymptomatic however it can lead to certain conditions. What conditions are associated with Hypertension?

Answer 3

Hypertension can lead to reduced life expectancy, left ventricular wall thickening, atheroma, stroke, coronary heart disease.

Question 4

Arteriosclerosis rises in response to hypertension, what is this process?

Answer 4

Arteriosclerosis is a process involving the thickening of the muscular layer of the walls of the arteries. Termed hardening of the arteries.

Question 5

When diagnosed with Hypertension what are the initial steps taken in reducing its effects?

Answer 5

To begin the patient would be advised to reduce bodyweight, salt intake, alcohol consumption and smoking.

Question 6

What drug treatment is offered to patients after initial advice is given and what would impact which drug is given?

Answer 6

ACE inhibitors and ARAs are offered to patients with high renin hypertension.
Where as a patient with low renin hypertension would be offered a calcium channel blocker.

Question 7

If initial single drug treatment isn’t effective to the patient, what steps are taken in terms of drug treatment?

Answer 7

The patient would be given a combination of the drugs in this case it would be ACE inhibitors/ ARAs along with a calcium channel blocker.

Question 8

Triple therapy is offered to patients to control severe hypertension, What is meant by the term “triple therapy” and what drugs are given?

Answer 8

Triple therapy is a now a combination of three drugs and these drugs would be ACE inhibitors/ ARAs, a calcium channel blocker and a diuretic.

Question 9

What other therapeutic agents may be used when triple therapy fails to control hypertension?

Answer 9

Further Diuretics, alpha and beta blockers would be used to control the patients hypertension.

Question 10

A class of drugs used to reduce the effects of hypertension is termed Vasodilating. What is meant by this term and how does this help with treating hypertension?

Answer 10

Vasodilating drugs cause a blood vessels muscular walls to relax (dilation) as a result it lowers blood pressure as there is less pressure required to move blood around the body.

Question 11

ACE inhibitors are used to affect which physiological system?

What does this system maintain within the body?

Answer 11

ACE inhibitors are used to affect the renin-angiotensin system, this system is used to maintain blood pressure and Sodium ion concentration.

Question 12

Describe the RAS system step by step:

1) …. is released in response to ….. and ……
2) ….. acts on ……. to form …….
3) ….. passes through the …… and is converted into …. by the ……..

Answer 12

1) Renin is released in response to a falling sodium ion concentration and reduced renal pressure.
2) Renin acts on angiotensinogen to form angiotensin I.
3) Angiotensin I passes through the lungs and is converted into Angiotensin II by the angiotensin converting enzyme

Question 13

Angiotensin II is a product produced by RAS, how does this molecule aid the system in maintain blood pressure ?

Answer 13

Angiotensin II is a vasoconstrictor which increases blood pressure and also stimulates the release of aldosterone to increase sodium ion reabsorption meaning more water is retained and blood volume is increased again increasing pressure.

Question 14

What will ACE inhibitors effect in the RAS?

Answer 14

ACE inhibitors will stop the conversion of angiotensin I to angiotensin II meaning the vasoconstrictor is not produced and brood pressure will fall.

Question 15

What side effects are associated with the use of ACE inhibitors and what causes these side effects to occur ?

Answer 15

Dry Cough and Angioedema are side effects related to ACE inhibitor use, these occur due to the accumulation of bradykinin, this accumulates as the kinases that usually break it down are inhibited.

Question 16

ARAs are used secondary to ACE inhibitors. Why are these used and how does these affect the RAS?

Answer 16

Angiotensin receptor antagonists are used when the dry cough side effect experienced with ACE inhibitor use cannot be tolerated. These affect the RAS by blocking the angiotensin II receptors so angiotensin II can not produce a vasoconstriction but is still produced as the enzymes that convert and the kinases that breakdown bradykinin are not inhibited.

Question 17

How is the release of calcium ions activated ?

How does the release of calcium ions then result in increased blood pressure?

Answer 17

Calcium ions are released when activation of the alpha1-adrenoreceptor stimulates phospholipase C to produce inositol trisphosphate

Calcium ions then increases blood pressure by binding to calmodulin, which causes MLC to become phosphorylated which cause muscle protein filaments to interact causing a muscle contraction and vasoconstriction.

Question 18

Where are Calcium channel blockers used and how does this mechanism lower blood pressure?

Answer 18

Calcium channel blockers are used to block L-type Calcium ion channels this reduces the amount of ion that enter. The reduced number of Calcium ions means that less ions bind causing a reduction in contraction and decrease in resistance hence lowering BP.

Question 19

How do alpha1-adrenoreceptor antagonists cause a fall in blood pressure?

Answer 19

Alpha1-adrenoreceptor antagonizes vascular alpha, this caused the vessel to dilate, reducing resistance and causing a fall in blood pressure.

Question 20

What do hydralazines act on to reduce blood pressure?

Answer 20

Hydralazines interfere with vessel muscles inositol trisphosphate this as a results causes a reduction in resistance and reduced blood pressure.

Question 21

What mechanisms of action is used by Minoxidil to cause a vasodilation?

Answer 21

Minoxidil causes hyperpolarization by opening K+ATP channels this means that Calcium ion entry is reduced causing reduced muscle contraction and a vasodilation.

Question 22

Beta Blockers have 2 mechanisms when treating hypertension:

i) Acute
ii) Chronic

Describe each mechanism.

Answer 22

The acute action of beta blockers involves blocking beta1-adrenoceptors this will cause heart rate and cardiac output to fall lowering blood pressure.

The chronic mechanism of beta blockers is where the amount of blood pumped out be the left ventricle is recovered but blood pressure remains low, this is believed to be due to a reset in resistance, reduced renal renin release and reduced sympathetic outflow ( triggers beta1-adrenoceptors).

Question 23

Give an example of a patient population where beta blockers should not be given and why?

Answer 23

Asthmatics should not be given beta blockers due to trigger of a bronchoconstriction.

Patients with hypoglycaemia as glucose released by adrenaline is used as a warning and this response is stopped by beta blockers.

Question 24

What adrenoceptors do centrally acting drugs interact in with, what effect is exhibited and what does this result in?

Answer 24

Centrally acting drugs act on the alpha2-adrenoreceptors, being a agonist at this receptor its causes the release of noradrenaline which causes a vasodilation resulting in reduced heart rate and cardiac output.

Question 25

What is special about the centrally acting drug methyldopa?

Answer 25

It can be used to treat Hypertension during pregnancy.

Question 26

Diuretics is used in combination with ACE inhibitors and Calcium channel blockers to aid treatment. How do Diuretic drugs work ?

Answer 26

Diuretic drugs increase the volume of urine produced, which is made from water excreted from the blood this means that the volume of blood is decreased.

Question 27

Thiazides are an example of diuretics. How do Thiazides increase urine volume ? And how do this affect patients with hypertension ?

Answer 27

Thiazide inhibit the apical symporter this means that sodium chloride remains in the tubule cell, as a result to maintain osmotic balance water is excreted into the tubule cell. This reduces blood volume but also had a direct vasodilating effect caused by reduced sodium concentration contributing to the treatment of hypertension.

Question 28

Loop diuretics work similar to thiazides but they differ in where their action takes place and what inhibited. Explain these differences.

Answer 28

Loop diuretics work by causing a diuresis in the thick ascending limb of the loop of henle by inhibiting cotransport of sodium potassium and chloride ions.

Question 29

Diuretics can be described as either high ceiling or low ceiling agents. What is meant by these terms?

Answer 29

High ceiling agents means that when the dose is increased the effect will increase which is opposite for low ceiling agent as the effect won’t increase with dose increase.

Question 30

What are the 3 types of diuretics?

Answer 30

Thiazides, loop and potassium sparing.

Question 31

For what reason are potassium sparing diuretics used in combination with the other diuretics?

How is this reason achieved?

Answer 31

Potassium sparing diuretics are used to prevent hypokalaemia.

Hypokalaemia is avoided when these diuretics reduce the reabsorption of sodium ions in the lumen of nephrons. Reducing this means there is a a reduced need of potassium and hydrogen ions as there is no negative electropotential created and potassium ions are retained.