Treatment of Hypertension Flashcards
How is blood pressure physiologically controlled?
- Autonomic nervous system
- Renin-angiotensin system
- Bradykinin
- Endothelin
- Nitric oxide
- Atrial natriuretic peptide
What organs might be damaged by high blood pressure?
- Heart
- Kidneys
- Brain
- Eyes
How does high blood pressure lead to organ damage?
Increased arterial thinking caused by smooth muscle cell hypertrophy and accumulation of vascular matrix causes loss of arterial compliance, and thus organ damage
What is hypertension defined as?
140/90mmHg
What are the categories of hypertension causes?
- Primary (essential) hypertension
- Secondary hypertension
What is primary hypertension?
High BP without any single evident cause
What % of the hypertensive population have primary hypertension?
90%
What is secondary hypertension?
High BP with discrete, identifiable underlying cause
What % of the hypertensive population have secondary hypertension?
10%
How should hypertension be treated?
- Identify and treat underlying cause if present
- Identify and treat other cardiovascular risk factors or co-morbidities
- Lifestyle advice and non-pharmacological therapy
- Pharmacological therapy
What is the optimal blood pressure?
<120/<80mmHg
What is considered to be normal blood pressure?
<130/<85mmHg
What is considered to be high normal blood pressure?
130-139/85-89mmHg
What is considered to be grade 1 (mild) hypertension?
140-159/90-99mmHg
What is considered to be grade 2 (moderate) hypertension?
160-179/100-109mmHg
What is grade 3 (severe) hypertension?
>180/>110mmHg
What is considered to be grade 1 isolated systolic hypertension?
140-159/<90mmHg
What is considered to be grade 2 isolated systolic hypertension?
>160/<90mmHg
What lifestyle therapy can be used in hypertension?
- Patient education
- Maintain normal body weight
- Reduce salt intake to <6g/day
- Limit alcohol consumption to <3units/day for men, <2units per day for women
- Engage in regular aerobic physical exercise for >30min/day
- Consume >5 portions of fresh fruit/veg daily
- Reduse intake of total and saturated fat
- Smoking cessation
What are the first line pharmacological therapies in the treatment of hypertension?
- Angiotensin Converting Enzyme (ACE) inhibitiors/angiotensin receptor blockers
- Calcium channel blockers
- Diuretics
What are ACE inhibitiors?
Competitive inhibitiors of angiotensin converting enyzme
What are the effects of ACE inhibitors?
- They reduce the formation of angiotensin II
- Cause arteriolar vasodilation, with some venodilation
- Circulating aldosterone reduced
Give two examples of ACE inhibitors
- Lisinopril
- Ramipril
What is the main side effect of ACE inhibitors?
Dry cough, which occurs in 10-15% of people
What are the important side effects of ACE inhibitors?
- Angio-oedema
- Renal failure
- Hyperkalaemia
In whom is angio-oedema caused by ACE inhibitors more common?
Black populations
Give two examples of angiotensin receptor blockers
- Lorsartan
- Valsartan
How do angiotensin receptor blockers work>
They bind to the angiotensin AT1 receptor, and inhibit vasoconstriction and aldosterone stimulation caused by angiotensin II
What are the side effects of angiotensin receptor blockers?
They are well tolerated, so few side effects, but important side effects are;
- Renal failure
- Hyperkalaemia
What is the mechanism of action of calcium channel blockers?
They bind to specific alpha subunits of L-type calcium channels, reducing cellular calcium entry
What are the main groups of calcium channel blockers?
- Dihydropyridines
- Benzothiazepines
- Phenylalkylamines
Give two examples of dihydropyridines
- Nifedipine
- Amlodipine
Give an example of a benzothiazepine
Dilitiazem
Give an example of a phenylalkylamine
Verapamil
What vessels do calcium channel blockers cause vasodilation in?
Peripheral, coronary, and pulmonary arteries
No significant effect in veins
What effect on the heart rate do short acting dihydropyridines have?
Cause baroreflex mediated tachycardia
What effect does verapamil have on the heart?
Depresses SA node and slows AV conduction
What are the pharmacokinetic properties of dihydropyridine calcium channel blockers?
- Good oral absorption
- Protein bound >90%
- Metabolised by liver
- Few have active metabolite