Hypertension Flashcards
What is hypertension?
Hypertension is defined as 140/90 mmHg
What is primary and secondary hypertension?
- Primary hypertension is without single evident cause
- Secondary hypertension is high blood pressure with a discrete identifiable underlying cause and it is less common
What is the 1st line treatment for hypertension?
- ACE inhibitors
- Calcium Channel Blockers
- Diuretics
What are some example of ACE inhibitors?
- Lisinopril
- Ramipril
What is the mechanism of action demonstrated by ACE inhibitors?
- Inhibition of Angiotensin Converting Enzyme activity
- Prevents generation of Angiotensin 2
What are the effects of ACE inhibitors?
- Some venodilation
- Mainly vasodilation
- Circulating aldosterone is reduced
- Potentiates the action of bradykinin
This cause lowering of Blood Pressure
What are the indications of ACE inhibitors?
- Heart Failure
- LV dysfunction
- Myocardial infarction
- Diabetes
- Nephropathy
What are the side effects of ACE-inhibtors?
- Dry Cough
- Angio-oedema
- Renal failure
- Hyperkalaemia
What are some contraindications of ACE inhibitors?
- Pregnancy
- Renovascular Hypertension
- Renal impairment
- Pulmonary vascular disease
What are some examples of angiotensin receptor blockers?
- Losartan
- Candesartan
What is the mechanism of action demonstrated by angiotensin receptor blockers?
Binds to angiotensin AT1 receptor
- Inhibits Vasoconstriction
- Inhibits aldosterone stimulation caused by angiotensin 2
This leads to blood pressure lowering
When are angiotensin receptor blockers used?
- ACE inhibitor intolerance
- Hypertension with LVH
- Type 2 Diabetes Mellitus
What are the side effects of angiotensin receptor blockers?
- Renal failure
- Hyperkalaemia
What are some contraindications of angiotensin receptor blockers?
- Pregnancy
- Renovascular hypertension
- Renal impairment
- Pulmonary vascular disease
What are the types of calcium channel blockers?
- Dihydropyridines
- Phenylalkylamines
- Benzothiazepines
What are some examples of Dihydropyridines?
- Amlodipine
- Nifedipine
What are the effects of Calcium Channel Blockers?
- Vasodilates peripheral, coronary and pulmonary arteries
- No significant effect on veins
What are the properties of Dihydropyridines?
- Good oral absorption
- Protein bound >90%
- Metabolised by the liver
- Few have active metabolite
What are some uses of Dihydropyridines?
- Blood pressure lowering
- Short acting dihydropyridines affect the baroreceptor mediated tachycardia
- Used in the elderly and ISH
What are some side effects of Dihydropyridines?
- Oedema commonest
- Sympathetic nervous system activation leading to tachycardia and palpitations
- Flushing, sweating, throbbing headache
- Gingival hyperplasia
What are the properties of Phenylalkylamines?
- Impedes calcium transport across the myocardial and vascular smooth muscle cell membrane
- Class 4 anti-arrhythmic agent/prolongs the action potential/effective refractory period
- Peripheral vasodilation and a reduction in cardiac preload and myocardial contractility
What are some properties of Benzothiazepines?
- Impedes calcium transport across the myocardial and vascular smooth muscle cell membrane
- Prolongs the action potential/effective refractory period
- Peripheral vasodilation and a reduction in cardiac preload and myocardial contractility
What are the uses of Phenylalkylamines?
- Blood pressure lowering
- Verapimil depresses the SA nodes and slows AV conduction
- Used in Angina
What are the main side effects of Phenylalkylamines?
- Constipation
- Risk of bradycardia
- Reduce myocardial contractility (negative inotrope) - Worsen heart failure
What are the contraindications of Phenylalkylamines?
- Heart block
- Heart failure
- Careful with combination with beta-blockade
What the uses of Benzothiazepines?
Bood pressure lowering
What are the side effects of Benzothiazepines?
- Risk of bradycardia
- Less negative ionotropic effect than verapamil - can worsen heart failure
What are some examples of Thiazide/Thiazide Like diuretics?
- Bendroflumethiazide
- Indapamide
What are some effects of thiazide/thiazide like diuretics?
- Reduce distal tubular sodium reabsorption
- Sustained action
- Blood pressure reduction complex. Has some vasodilator properties as well as venodilation
- Dose-blood pressure response curve: flat
What are some uses of thiazide/thiazide like diuretics?
- Blood pressure reduction by several mechanisms by initial blood volume decrease and later total peripheral resistance falls
- Used in elderly patients, heart failure patients and ISH
What some side effects of thiazide/thiazide like diuretics?
- Hypokalaemia
- Increased urea and uric acid levels
- Impaired glucose tolerance (especially with beta-blockers)
- Cholesterol and triglyceride levels increased
- Activates RAAS
What are some contraindications of Thiazide/Thiazide like diuretics?
-Gout
What are some examples of alpha blockers?
Doxazosin
What are some effects of alpha blockers?
- Selective antagonism at post-synaptic alpha 1 adrenoceptors and antagonise the contractile effects of noradrenaline on vascular smooth muscle
- Reduce peripheral vascular resistance
- More effect in upright position
- Benign effect on plasma lipids/glucose
- Safe in renal disease
What are the uses of Alpha blockers?
Blood pressure reduction
What are the side effects of alpha blockers?
- Postural hypotension and dizziness
- Headache and fatigue
- Oedema
What the contraindications of alpha blockers?
- Urinary Incontinence
- Postural hypotension
- Heart Failure
What are some examples of Beta Blockers?
- Atenolol
- Bisoprolol
- Nebivol
- Propanolol
- Esmolol
What are the physiological effects of Beta Blockers in heart failure?
- Reduce heart rate - Cardiac beta receptor
- Reduce blood pressure - Reduce cardiac output.
The combination of 1+2 leads to reduced myocardial oxygen demand
- Reduce mobilisation of glycogen
- Negative unwanted effects of catecholamines
What are the effects of Beta Blockers?
- Reduce heart rate and cardiac output
- Inhibit renin release
- Initially TPR increases later falls to normal
What are uses of Beta Blockers?
- Blood pressure reduction
- Used in MI/Angina
What are the side effects of beta blockers?
- Lethargy impaired concentration
- Reduced exercise tolerance
- Bradycardia
- Cold hands - Raynaud’s
- Impaired glucose tolerance
What are the contra-indications of Beta blockers?
- Asthma
- Heart block
- Heart failure
- PVD (caution)
- Diabetes except with CHD
What is the mechanism of action demonstrated by Aliskeren?
- Direct renin inhibition by suppression at the point of activation
- Reduces plasma renin activity by 50% - 80%
- Blood pressure reduction by vasodilation
What are the types of Centrally acting agents and how do they work?
Reduce sympathetic outflow
- Methydopa: converted to alpha methyl noradrenaline - a potent alpha-2 adrenoceptor agonist
- Clonidine: Direct pre-synaptic alpha 2 adrenoceptor agonist
- Moxonidine: imidozoline receptor agonist and some alpha 2 agonist effect
What are the uses of centrally acting agents?
-Used in hypertension however less commonly
What are the side effects of centrally acting agents?
- Tiredness/lethargy
- Depression
How are combination therapies used effectively in hypertension?
- Hydrochlorthiazide: Thiazide diuretic which lowers BP and raises glucose as well as lowering K+
- Amiloride: K+ sparing diuretic which lowers BP and has no effect on glucose
Combination of the 2 at half dose result in greater decrease in BP with no effect on K+ and glucose
What are the principles of managing heart failure?
Correct underlying cause
Non-pharmacological measures
Pharmacological therapy
- Symptomatic improvement
- Delay progression of heart failure
- Reduce mortality
Treat complications/associated conditions/cardiovascular risk factors
How are beta blockers administered in heart failure?
- Care need to be taken. Failing myocardium dependant on heart rate
- Initiate at low dose and titrate slower. May have to alter concomitant medication such as diuretics
What are examples of Phenylalkylamines?
Verapamil
What are examples of Benzodiazepines?
Diltiazem
