Antihypertensives

Question 1

Hypertension

Answer 1

Occurs when the force of blood against the walls of your arteries is constantly too high.
Is diagnosed when blood pressure readings are constantly at or above 140/90mmHg

Question 2

Mechanisms for controlling blood pressure

Answer 2

Understand and take it easy
A. Baroreceptors and the sympathetic nervous system:
a fall in blood pressure causes pressure sensitive neurons (baroreceptors in the aortic arch and carotid sinuses) to send fewer impulses to cardiovascular centers in the spinal cord.
This prompts a reflex response of increased sympathetic and decreased parasympathetic resulting in vasoconstriction and increased cardiac output.
B. Renin angiotensin aldosterone system: baroreceptors in kidney respond to reduced arterial pressure by releasing the enzyme renin.
Low sodium intake and greater sodium loss also increase renin release . Renin converts angiotensongen to angiotensin 1 ,which is converted to 11 in the presence of ACE .
Angiotensin 11 vasoconstrictor leading to increase blood pressure furthermore angiotensin 11 stimulates aldosterone secretion leading to increased renal sodium reabsorption and increased blood volume which contribute to a further increase in blood pressure.

Question 3

Hydrochlorothiazide

Answer 3

Lower blood pressure initially by increasing sodium and water excretion. This causes a decrease in extracellular volume resulting in a decrease in cardiac and peripheral resistance.
They are not effective in patients with poor kidney function.
Adverse effects:
Hypokalemia
Hyperuricemia
Hypomagnesemia

Question 4

Potassium sparing diuretics

Answer 4

1- amiloride- inhibiting sodium reabsorption in the kidney. And reduce potassium loss in the urine.
2- spironolactone has the additional benefit of diminishing the cardiac remodeling that occurs in the heart failure

Question 5

Substances affecting the sympathetic nervous system

Answer 5

@ blockers
B blockers
Sympatholytic

Question 6

@ blockers

Answer 6

Reduce blood pressure through vasodilation due to blocade of the @receptors .

Question 7

B blockers

Answer 7

Atenolol and propranolol
The following sites of action:
Decreased cardiac output
Reduced renin release by the kidney.
Decrease norepinephrine release

Question 8

Sympatholytic

Answer 8

Reserpine and clonidine
Blood pressure reducing agents

Question 9

ACE inhibitors

Answer 9

Captopril
Enalapril
Lisinopril
Perindopril
Side effects include cough , headache, nausea, dizziness, hypotension, photosensitivity and allergic skin reaction

Question 10

Calcium channel blockers

Answer 10

Verapamil
Nifedipine
Diltiazem
Isradipine
Causes vasodilation
Are especially effective in elderly

Question 11

Vasodilators with direct action on smooth muscle.

Answer 11

Dihydralazine and hydralazine
Minoxidil
Nitroprusside sodium
Diazoxide

Question 12

Side effects of di and hydralazine

Answer 12

Due to blood pressure reduction induced reflexive sympathetic activation and include increase in heart rate and stroke volume. Headache , dizziness , diarrhea.

Question 13

Sodium nitroprusside

Answer 13

Has extremely short duration of action
Is indicated for the treatment of blood pressure crises. As well as for certain surgical procedures.
Adverse effects
After a too rapid infusion , unconsciousness and loss of pulse can occur due to excessive decrease in blood pressure.
A longer treatment with sodium nitroprusside carries the risk of thiocyanate accumulation which can cause speech impairment,weakness muscle.