Hypertension And Heart Failure Drugs

Question 1

What does lowering blood pressure by 10mmHg achieve?

Answer 1

Reduction in stroke (58%)

Reduction in coronary heart disease (37%)

Question 2

Name some secondary causes of hypertension

Answer 2

Renal parenchymal disease, pheochromocytoma, Conn’s syndrome, Cushing’s syndrome, coarctation of the aorta

Question 3

What are the 3 grades of hypertension?

Answer 3

Grade 1 - >140/90

Grade 2 - >160/100

Grade 3 - >180/110

Question 4

What determines the threshold for treatment?

Answer 4

Sustained blood pressure (grade 2 justifies)

Cardiovascular risk - >15% risk of event in the next 10 years, the presence of end organ damage

Question 5

When is treatment justified for grade 1 regardless of cardiovascular risk and what is the target blood pressure for this group?

Answer 5

Diabetes - <130/80

Question 6

Outline the treatment guidelines for hypertension

Answer 6

> 55 - Ca2+ blocker/thiazide diuretic

<55 - ACE inhibitor (ARB if cough ADR with ACE inhibitor)

If still uncontrolled - ACE inhibitor + Ca2+ blocker/thiazide diuretic

If still uncontrolled - ACE inhibitor + Ca2+ blocker + thiazide diuretic

If still uncontrolled - add other diuretic e.g. Spironolactone/a blocker/b blocker/renin inhibitors/centrally acting drugs, vasodilators

Question 7

Name an ACE inhibitor and describe how it works

Answer 7

Lisinopril, ramipril - lowers angiotensin levels resulting in vasodilation and natriuresis (reduces vasoconstriction, aldosterone release and increased sympathetic activity)

Question 8

What are the main ADRs of ACE inhibitors?

Answer 8

Cough (potentiates bradykinin)

Hypotension

Nephrotoxic when given to patient with renal stenosis

Hyperkalaemia

Angio-oedema

Question 9

How do Ca2+ channel blockers treat hypertension?

Answer 9

They bind to the a subunits of L-type Ca2+ channels to reduce cellular Ca2+ entry. They mainly work by causing vasodilation but verapamil also reduces cardiac preload and contractility (also depresses the SA node to slow A-V conduction)

Question 10

What are the 3 types of Ca2+ blockers and their ADRs?

Answer 10

Dihydropyridines e.g. Amlodipine - sympathetic nervous system activation (tachycardia, palpitations), vasodilator effects (flushing, sweating, throbbing headache, oedema)

Benzodiazepines e.g. Diltiazem - bradycardia, worsening of heart failure (inotropy)

Phenylalkylamines e.g. Veramapil - constipation, bradycardia, hypotension, worsening of heart failure (inotropy)

Question 11

What drug type should you not prescribe with verapamil?

Answer 11

B blocker

Question 12

How do thiazide diuretics work?

Answer 12

Block Na-Cl symporter in the distal convoluted tubule to reduce the initial blood volume and later total peripheral resistance falls

Question 13

What are the main ADRs of thiazide diuretics?

Answer 13

Hypokalaemia, increased urea and ureaic acid, impaired glucose tolerance, high cholesterol and triglycerides, can activate RAS

Question 14

How would you treat a hypertensive emergency?

Answer 14

Sodium nitroprusside - mimics endogenous nitric oxide on vascular smooth muscle to cause vasodilation. It is given IV, is broken down to cyanide (caution with liver disease), excreted in urine, avoid use >72 hours

BP needs to be reduced by 20%/to 100mmHg in 1-2 hours

Question 15

What are the guidelines for treating heart failure?

Answer 15

Loop diuretic e.g. Furosemide

ACE inhibitor/ABR

B blocker

If uncontrolled consider + thiazide, spironolactone, digoxin, vasodilator

Question 16

In heart failure which drugs improve prognosis?

Answer 16

ACE inhibitor/ARB, b blocker

Diuretics do not improve prognosis but are useful for treatment

Question 17

What study looked at ramipril reducing mortality?

Answer 17

AIRE

Question 18

What study looked at spironolactone increasing survival in patients on ACE inhibitors, loop diuretics and digoxin?

Answer 18

RALES