Drugs for Hypertension

Question 1

what is primary “essential” hypertension?

Answer 1

• no known cause, represents 90-95% of cases

- genetic predisposition, dietary salt intake, adrenergic tone

Question 2

what is secondary hypertension?

Answer 2

• known cause; represents 5-10% of cases

- ex. adrenal cortical tumours, drugs

Question 3

what are the physiological effects of hypertension?

Answer 3

• prolonged force on vessels thickens muscles in the arterial system
• heart constantly works harder to expel blood against a greater force, increasing the workload of the heart
• increase force damages inner lining of arteries (susceptible to atherosclerosis and to narrowing of vessel lumen)
• tiny vessels are damaged and destroyed leading to losses in vision, kidney function and cerebral function

Question 4

what is hypertension a risk factor for?

Answer 4

• CVA, CAD, CHF, cardiac death, renal failure, peripheral vascular disease, and dementia

Question 5

what parameters control BP?

Answer 5

• BP=CO X peripheral resistance
• CO: product of heart rate and amount of blood that is ejected with each beat (stroke volume)
• peripheral resistance: arteries possess smooth muscle in the media that responds to alpha 1 receptors. when stimulated they produce contraction of the smooth muscle layer and increase lumen of the vessel increasing peripheral resistance

Question 6

what is the compensatory action by kidneys to regulate blood pressure?

Answer 6

• engages kidneys to increase urine output, reducing blood volume and stroke volume decreasing blood pressure

Question 7

what is the compensatory action of the cardiovascular system to regulate blood pressure?

Answer 7

• decreases in heart rate cause decrease in cardiac output, which decreases blood pressure; also causing vasodilation in periphery

Question 8

what are some lifestyle modifications with hypertension?

Answer 8

• reduce sodium intake
• healthy diet
• low risk alcohol consumption
• regular physical activity
• maintenance of ideal body weight
• smoking cessation
• stress management

Question 9

why should beta blockers not be used as a mono therapy for hypertension in those 60+?

Answer 9

• do not help to decrease the risk for myocardial infarction or stroke

Question 10

what is the mechanism of action of thiazide and thiazide- like diuretics?

Answer 10

• first line therapy for management of hypertension
• reduces stroke volume by blocking sodium/chloride transporter in the distal tubule facilitating the excretion of electrolytes

Question 11

what are some caution precautions when using thiazide diuretics?

Answer 11

• severe renal disease, diabetes, GOUT, liver disease, hyperlipidemia

Question 12

when are thiazide diuretics contraindicated?

Answer 12

• pregnancy

Question 13

when should thiazide diuretics be administered?

Answer 13

• during the day to prevent nocturia

Question 14

what are some adverse effects of thiazide diuretics?

Answer 14

• GI upset, orthostatic hypotension, hyperglycaemia, fluid and electrolyte imbalance

Question 15

what are some drug to drug interactions with thiazide diuretics?

Answer 15

• lithium, NSAIDs, anti diabetic drugs

Question 16

what is important to monitor with thiazide diuretics?

Answer 16

• sodium and potassium levels, kidney function and blood pressure within 4-6 weeks of starting therapy
• dizziness and lightheadedness

Question 17

what is the mechanism of action of angiotensin converting enzyme (ACE inhibitors)?

Answer 17

• decreases peripheral resistance and decrease blood volume
• blocks conversion of angiotensin I to angiotensin II
• increase production of vasodilatory kinins
• inhibits aldosterone secretion

Question 18

when are ACE inhibitors contraindicated?

Answer 18

• in pregnancy, use caution with potassium-sparing supplements and diuretics
• decreased antihypertensive activity with NSAIDS

Question 19

what are some adverse effects with ACE inhibitors?

Answer 19

• may induce dry cough
• hyperkalemia
• GI irritation and constipation
• sudden drop in BP (first dose phenomenon)
• allergic reaction of the lips, mouth, and throat occurring during first month of administration

Question 20

what is the mechanism of action of angiotensin II receptor blockers?

Answer 20

• decrease peripheral resistance and decreases blood volume
• block angiotensin II receptors in arteriolar smooth muscle and in adrenal cortex
• inhibit the release of aldosterone
• no effect on bradykinin

Question 21

what type of patients are prescribed angiotensin II receptor blockers?

Answer 21

• people who cannot tolerate adverse effects of ACE inhibitor drugs

Question 22

what are the common adverse effects and drug to drug interactions with angiotensin II receptor blockers?

Answer 22

• similar to ACE inhibitors

Question 23

what is the mechanism of action for calcium channel blockers?

Answer 23

• block calcium ion channels
• relax vascular smooth muscle, decreasing peripheral resistance
• slow heart rate , reducing cardiac output and cardiac workload

Question 24

when should you be cautious administering calcium channel blockers?

Answer 24

• in those with liver and kidney impairment

Question 25

what are some adverse effects of calcium channel blockers?

Answer 25

• dizziness
• light-headed
• fatigue
• flushing
• nausea

Question 26

what should be avoided when taking calcium channel blockers?

Answer 26

• avoid grapefruit juice, increases serum CCB levels

Question 27

what part of the autonomic nervous system increases heart rate and smooth muscle constriction of arterial walls?

Answer 27

• sympathetic division

Question 28

what is the mechanism of action of alpha and beta adrenergic receptors?

Answer 28

• block adrenergic effects on arterioles
• block action of NE and E on cardiac muscle reducing speed and force of contraction
• decrease renin secretion by the kidneys, reducing the production of angiotensin I and decreasing TPR

Question 29

when are beta blockers most effective?

Answer 29

• in patients under the age of 60 with concomitant cardiovascular conditions
• previous history of MI and/or angina

Question 30

what would be some patient precautions when taking beta adrenergic antagonists?

Answer 30

• diabetes, depression, asthma, COPD

- reduction in heart rate may cause fatigue and activity intolerance