Session 9 - Hypertension and Heart Failure Flashcards
Is blood pressure a disease?
No, it’s a risk factor for future vascular disease
How does higher blood pressure cause organ damage?
Higher Blood Pressure -> Increased arterial thickening -> Smooth muscle cell hypertrophy and accumulation of vascular matrix -> Loss of arterial compliance -> end organ damage
What are the five organ systems affected by sustained hypertension?
Brain Heart Arterial System Kidney Eye
What two conditions is blood pressure a good indicator of?
Ischaemic heart disease and stroke
What are the two types of hypertension and which is more common?
Primary and secondary
Primary high BP with unkown cause - 90% pop
Secondary - Known cause
10% pop
What two factors determine whether drug therapy is offered to a patient or not?
The sustained level of blood pressure
The overall cardiovascular risk profile
What is hypertension defined as?
BP over 140/90
What is the effect of lowering diastolic BP by 10mmHg?
58% reduction in strokes
37% reduction in coronary artery disease
What level of hypertension justifies drug treatment
≥ 160mmHg Systolic and ≥100mmHg diastolic justifies drug treatment
What is the overall cardiovasc risk profile?
Is there > 15% risk of a cardiovascular event in the next 10 years?
Presence of end organ damage?
In the presence of diabetes the treatment threshold is 140/90mmHg
What are the four non-pharmocological factors that will modify decision to insitute a drug regime
o Optimum body weight (BMI 20-25 kg/m2)
o Regular physical activity (>30 mins a day)
o Moderation of alcohol and salt. (< 2 units for women. < 6g salt)
o Smoking cessation should be strongly advised, and supported as necessary (e.g. nicotine replacement therapy)
What is severe hypertension?
> 180/>110
What is mild hypertension?
140-159/90-99
Name three ace inhibitors
Ramipril
Lisinopril
Captopril
What is the mech of action of ACE inhibitors in lowering blood pressure
ACE inhibitors cause inhibition of Angiotensin Converting Enzyme, consequently reducing Angiotensin II and Aldosterone levels. This causes vasodilation and consequent reduction in peripheral resistance and reduced sodium retention.
Reduce breakdown of the vasodilator Bradykinin
Give three indications for ACE inhibitors?
Hypertension
Heart failure
Renal dysfunction
Give three contraindications for ACE inhibitors
Pregnancy, renovascular disease, aortic stenosis
Give five adverse drug reactions of ACE inhibitors
Characteristic dry cough
Angio-oedema (rare, but more common in black population)
Renal Failure
Hyperkalaemia
Hypotension, dizziness and headache, diarrhoea and muscle cramps
Give two angiotensin blockers
Losartan
Valsartan
Give an indication for an angiotensin blocker
Hypertension
When would you not use an angiotensin blocker?
Pregnancy, breastfeeding
Caution in renal artery stenosis and aortic stenosis
Give a mechanism of action of an angiotensin blocker?
Bind to and antagonise the receptor for Angiotensin II – Angiotensin 1 Receptor (AT1 R).
Inhibits vasoconstriction and aldosterone stimulation by angiotensin II.
Give the main diuretic used in control of BP
Thiazide diuretics
Give a short list of drugs involved in BP management
ACE inhibitors
Angiotensin blocker
Beta blocker
Calcium Channel Blockers
Give four beta blockers
Propranolol
Atenolol
Bisoprolol
Metoprolol
Give the mechanism of action of beta blockers
Antagonise β-adrenoreceptors. β1-receptors are found in the heart, when they are activated they cause increased Chronotropy and Inotropy.
Inhibit renin release
Give four indications for beta blockers
Angina
Post myocardial infarction
Hypertension
Arrhythmias
Give a couple of contraindications for beta blockers
Non-selective β-blockers (e.g. Propranolol) must not be given to asthmatic patients.
Bradycardia, hypotension, AV block, Congestive Cardiac Failure
Give some adverse drug reactions to B blockes
Bronchospasm, fatigue and insomnia, dizziness, cold extremities, hypotension, bradycardia and decreased glucose tolerance in diabetic patients
Give two drug-drug interactions of beta blockers
Prevents Salbutamol working (β2-adrenoagonist)
Verapamil – Both have –‘ve inotropic action
Give three types of calcium channel blockers
Dihydropyridine
Phenylalkylamine
Benzothiazepine
What is the mechanism of action of calcium channel blockers?
o Calcium channel blockers bind to specific alpha subunit of L-type calcium channel, reducing cellular calcium entry
o Vasodilates peripheral, coronary and pulmonary arteries
o No significant effect on veins
o Verapamil depresses SA node and slows A-V conduction
Give two examples of dihydropyridine calcium channel blockers
Nifedipine
Amlodipine
Give three properties of 1. Dihydropyridine Ca2+ blockers
Good oral absorption
Protein bound > 90%
Metabolised by the liver
Give three adverse effects of dihydropyridine
Sympathetic nervous system activation – tachycardia and palpitations
Flushing, sweating, throbbing headache
Oedema
What is a phenylalkylamine calcium channl blocker?
Verapamil
Give three properties of verapamil (phelyalkylamine calcium channel blocker)
Impedes calcium transport across myocardial and vascular smooth muscle cell membrane
Class IV anti-arrhythmic agent (prolongs action potential/effective refractory period)
Peripheral vasodilation and a reduction in cardiac preload and myocardial contractility
Give three adverse effects of verapamil
Impedes calcium transport across myocardial and vascular smooth muscle cell membrane
Class IV anti-arrhythmic agent (prolongs action potential/effective refractory period)
Peripheral vasodilation and a reduction in cardiac preload and myocardial contractility
Give an example of a benzothazepine calcium channel bloceker
Diltiazem
Give three properties of a benzothazepine calcium channel bloceker
Impedes Calcium transport across the myocardial and vascular smooth muscle cell membrane
Prolongs the action potential/effective refractory period
Peripheral vasodilation and reduction in cardiac preload and myocardial contractility
Give two adverse effects of 3. Benzothiazepine Calcium Channel Blockers
Risk of bradycardia
Negative inotropic effect (less than Verapamil) can worsen heart failure
Name a direct renin inhibitor
Aliskiren
Give an indication for a direct renin inhibitor
Hyperension
Give to contraindicator
Pregnancy
Caution in patients at risk of hyperkalaemia, Na+ and volume depleted patients, severe renal impairment and renal stenosis
Give a mechanism of action a direct renin inhibitor
Antagonises Renin, preventing the conversion of Angiotensinogen Angiotensin I.
Reduces plasma renin activity by 50-80%
Give an adverse drug reaction of angio-oedema
Angio-oedema, hyperkalaemia, hypotension, GI disturbances
Give a therapeutic note for direct renin inhibitors
t½ of ~40 hours, supporting once daily doses
Mainly eliminated as an unchanged compound in faeces (78%)
Not metabolised via CYP450
What are two common combinations of blood pressure control?
o Diuretic and ACE inhibitor
o Diuretic and Beta Blocker
What is treatment patter in people under 55?
Primary is Ace inhibitor (A)
Secondary A+C or A+D
Third is A+C_D
Four is more diuretic, alpha blocker or beta blocker
What treatment pattern in people over 55 or black patients?
Primary is C or D
Secondary A+C or A+D
Third is A+C_D
Four is more diuretic, alpha blocker or beta blocker
