3 - Hypertension and Heart Failure Drugs Flashcards
What are the effects of hypertension and how is bp regulated?
- Increases arterial wall thickness by remodelling and hypertrophy. Stiffens the walls so they are less compliant
- Organ damage from lack of blood flow
- Regulated by RAAS, autonomic NS, bradykinin, NO and natriuretic peptides

What are the values that define hypertension and what are some of the causes?
>140/90
primary, secondary (conn’s, diabetes), isolated diastolic/systolic, white coat

What are target blood pressures (clinically and ambulatory) for different groups of people?
- <140/90 if less than 80 inc type II diabetes
- <150/90 if greater than 80
- <135/85 if type I diabetic

What is best practice when diagnosing hypertension?
- Sitting relaxed and arm supported
- Both arms should be within 15mm/Hg of each other, if not then repeat. Take highest reading
- Measure over a period of time including ambulatory and hoe machines
- CVD and organ damage should be assessed whilst waiting for hypertension confirmation

What are the stages of hypertension?
- Resistant hypertension at stage 3
- Emergency if >180/20 and clinical signs

What is prehypertension and how can progression of this be limited
>120/80 but less then 140/90
- Promote regular exercise
- Healthy balanced diet
- Reduce stress and increase relaxation
- Limit alcohol and caffiene intake
- Smoking cessation
- Reduce salt in diet

In general what are some classes of drugs that are used to treat primary hypertension?
- ACE inhibitors
- ARBs
- Calcium channel blockers
- Diuretics
- Alpha and Beta blockers

What is the mechanism of action of ACEi’s to treat hypertension?
Competitive inhibitors of Angiotensin Converting Enzyme:
- Reduce formation of angiotensin II
- Arteriole vasodilation
- Reduce circulating aldosterone so less ADH
- Build up of bradykinin which is a vasodilator as makes NO, good for low renin hypertensives

What are some examples of ACEi’s?
- Ramipril
- Lisinopril
What are some side effects of ACEi’s?
Side effects:
- Dry cough*
- Hypotension
- Hyperkalaemia* as loss of aldosterone
- Renal failure especially due to renal artery stenosis as efferent arteriole needs to constrict
- Angiooedema* due to BK, especially black population

What are some contraindications of using ACEi’s?
- Pregnancy (along with ARBs, can cause CVS and CNS defects and growth restriction and oligohydraminos)
- Hyperkalaemia
- NSAIDs, K+ raising drugs, antihypertensives
- AKD
- Breastfeeding
- Renal artery stenosis

What is the mechanism of action of ARBs?
- AngII mainly binds to AT1 receptor
- Inhibits vasoconstriction* better than ACEis as the AT1 receptor blocked so any AngII made from chymases can not work either
- Inhibits aldosterone stimulation*
- Less effective in low renin hypertensives as no effect on bradykinin

What are some examples of ARBs?
- Candesartan
- Losartan

What are some side effects and contraindications of ARBs as antihypertensives?
Side effects:
- No dry cough and angiooedema like ACEi
- Renal failure
- Hyperkalaemia
Contraindications:
- AKD
- Pregnancy and breast feeding
- Renal artery stenosis
- K+ raising drugs, NSAIDs, other antihypertensives

What is the mechanism of action of calcium channel blockers?
- Bind to alpha1 subunit of L-type calcium channel (VOCC), reducing cellular calcium entry causing vasodilation, reducing preload on the heart
- LTCC in vascuar smooth muscle, cardiomyocytes, SA and AV node. Different classes selective for different areas

If a patient had hypertension with low renin levels, what class of drug would be best to prescribe them first?
- CCB as doesn’t target RAAS
- ACEi as increases bradykinin
What are the three main classes of CCBs and give some examples for each?
- Dihydropyridines: amlodipine (long half life), nifedipine (selective for cerebral vasculature so used for subarachnoid haemorraghe), nimodipine
- Benzothiazapines: Diltiazem
- Phenylakylamines: Verapamil

Where do each of the classes of CCBs work in the body?
- Dihydropyridines: 1st line CCB most commonly used for hypertension. Selective for peripheral vasculature but little ino/chronotropic effect
- Phenylalkyamines: mainly act on myocardium, depress the SA node and slows AV conduction so negative inotropy. Used for SVTS. Can worsen heart failure so don’t give to a hypertensive with heart failure
- Benzothiazapines: Sit in the middle, act on myocardium and vascular smooth muscle, can worsen heart failure

What are the side effects and contraindications of the use of dihydropyridines (good oral absorption) for hypertension?
Side effects:
- Ankle swelling, flushing and headaches from vasodilation
- Palpitations as compensatory tachycardia
Contraindications:
- Unstable angina and severe aortic stenosis as the palpatations
- Amlodipine and simvastatin as increased effect of statin
- Other antihypertensives

What are the side effects and contraindications of the use of phenylalkylamines?
- Mainly used to treat arrhythmias (SVTs) and angina not HTN
Side effects:
- Constipation, bradycardia, heart block, cardiac failure
Contraindications:
- Poor LV function
- AV nodal conduction delay
- B-blockers, other antihypertensives, other antiarrhytmic agents
What are the properties and adverse effects of Benzothiazepines e.g. diltiazem?
- Properties (same as phenylalkylamines): impedes calcium transport across the myocardial and vascular smooth muscle cell membrane, peripheral vasodilation, ↓ myocardial contractility
- Adverse effects: bradycardia, can worsen heart failure

What thiazide/thiazide-like diuretics are used to treat hypertension and what is their mechanism of action?
Reduce distal tubular sodium reabsorption by blocking NaCl channel
- Initial blood volume decrease
- Later, total peripheral resistance falls
- RAAS compensates
- Useful over CCBs in oedema

What are some examples of thiazides?
- Bendroflumethiazide
- Indapamide (thiazide like)

What are some side effects and contraindications associated with the use of thiazides in treating hypertension?
Side effects:
- HypoK, hypoNa, hyperuricemia
- Arrhythmia
- Increased glucose
- Increased cholesterol and triglycerides
Contraindications:
- HypoK, HypoNa
- Gout
- NSAIDs, K+ lowering drugs













