Anti-hypertensives

Question 1

Describe the prescribing algorithm for hypertension (both pathways)

Answer 1

Step 1: ACEi/ARB for <55y/o, CCB >55 or Afro/Caribbean
Step 2: Prescribe ACEi/ARB or CCB
Step 3: Add Thiazide-like diuretic (indapamide)
Step 4: K<4.5 add spironolactone, K>4.5 add higher dose thiazide-like drug
Step 5: Consider alpha or beta-blockers

Question 2

What are the uses of ACEis and ARBs?

Answer 2

Hypertension (reduce risk of stroke, MI etc); Chronic heart failure; Ischaemic heart disease; Diabetic neuropathy; CKD (reduce proteinuria and progression of neuropathy)

Question 3

What is the MOA of ARBs

Answer 3

Block action of angiotensin II on the AT1 receptor

Question 4

What is the MOA of ACEis

Answer 4

Blocks action of ACE to prevent conversion of angiotensin I to angiotensin II
Angiotensin II is a vasoconstrictor and stimulates aldosterone secretion, reducing peripheral vascular resistance and reducing BP
Dilates efferent glomerular arteriole (slows progression of CKD)

Question 5

What are the side effects of ARBs and ACEis?

Answer 5

Hypotension (after first dose)
Dry cough in ACEi due to bradykinin buildup (ACE converts bradykinin to an inactive metabolite)
Hyperkalaemia due to reduced aldosterone levels
Renal failure (particularly in renal artery stenosis)
Taste disturbance (ACEi)
Rare- angioedema and anaphylactic reaction

Question 6

What are the contra-indications and interactions of ARBs and ACEis

Answer 6

Avoid in AKI, pregnancy or breastfeeding
Avoid other potassium raising drugs
Increased risk of renal failure with an NSAID

Question 7

What are the dihydropyridine and non-dihydropyridine CCBs?

Answer 7

Dihydros: Amlodopine and nifedipine
Non: Diltiazem and verapamil

Question 8

What is the MOA of CCBs

Answer 8

Decrease calcium entry in vascular and cardiac cells causing relaxation and vasodilation in arterial smooth muscle
Reduce myocardial contractility
Slow ventricular rate by suppressing conduction across the AVN
Decreases cardiac oxygen demand (reducing angina)
Dihydropyridines are more selective for vasculature and non-dihydropyridines are selective for heart (verapamil most cardioselective)

Question 9

What are the uses of CCBs

Answer 9

Hypertension; stable angina; Diltiazem/verapamil can be used to control heart rate in supraventriuclar arrhythmias; Raynaud’s

Question 10

What are the side effects of CCBs

Answer 10

Dihydropyridines—> Flushing, headache, palpitations, ankle swelling (caused by vasodilation and compensatory tachycardia)
Diltiazem—> Hypotension, bradycardia, heart failure, ankle swelling
Verapamil—> Hypotension, bradycardia, heart failure, constipation, flushing

Question 11

What are the contraindications and interactions of CCBs?

Answer 11

Dihydropyridines—> Avoid in unstable angina, can provoke collapse with severe aortic stenosis
Diltiazem—> Can cause heart block when used with B-blockers; Avoid in patients with poor LV function
Verapamil—> Heart block with B-blockers, avoid in patients with poor LV function

Question 12

What are the uses of B blockers

Answer 12

Ischaemic heart disease; Chronic heart failure; AF (first line for rate control); Supraventricular tachycardia; Hypertension

Question 13

Give 6 examples of B blockers and their uses

Answer 13

Bisoprolol- more beneficial in heart failure (cardioselective)
Atenolol- more water soluble so less likely to cross BBB (less neuro SEs, cardioselective)
Metoprolol- Along with above has left effect on beta2 bronchial receptors (cardioselective)
Propanolol- Lipid soluble, crosses BBB. Can reverse clinical symptoms in thyrotoxicosis and used pre-operative prep for thyroidectomy
Labetalol- First line pre-eclampsia, also causes arteriolar vasodilation lowering peripheral resistance
Timolol- Eyedrops in glaucoma

Question 14

What is the MOA of B blockers

Answer 14

Beta1 receptors= heart; beta2 receptors=smooth muscle of blood vessels and airways
Reduce force of contraction and speed of conduction of the heart, reduces cardiac work and o2 demand so increases coronary perfusion
Protect heart from chronic sympathetic stimulation in heart failure
Prolong refractory period of the AVN slowing the ventricular rate in AF
In SVT they break self-perpetuating (re-entry) circuits, restoring sinus rhythm
Hypertension: reduce renin secretion from the kidneys as this is due to beta1 receptors

Question 15

What are the side effects of B blockers

Answer 15

Fatigue; Cold extremities; headache; Dizziness; GI upset; Bradycardia; Hypotension; Sleep disturbance and nightmares; Reduces hypoglycaemic awareness; Impotence

Question 16

What are the contra-indications and interactions of B blockers

Answer 16

Bronchospasm in asthma (fine in COPD)
Low dose in heart failure, can impair cardiac function
Avoid atenolol in pregnancy, can cause growth retardation, labetalol better
Contraindicated in heart block, shouldn’t be used with non-dihydropyridine CCBs
Contraindicated in sick sinus syndrome