Lecture 30 Flashcards
What are the reasons to treat hypertension?
Untreated hypertension increases the risk of coronary thrombosis, stroke, renal failure, heart failure, aneurysm and retinopathy
What are the basic physiological components of blood pressure?
Cardiac Output*Peripheral resistance
What occurs in early hypertension to the basic physiological components of blood pressure?
Cardiac output increases while peripheral resistance stays the same, over time the cardiac output will normalise and the total peripheral resistance will increase
What are the main pharmacological targets for antihypertensive drugs?
The sympathetic nervous system
Blood vessels (endothelium derived autacoids such as Nitric oxide and endothelin-1 as well as vascular smooth muscle)
The renin-angiotensin-aldosterone system
Other targets include Blood volume and thickness
How can beta-1 receptor antagonists be used to treat hypertension?
They can reduce heart rate
How can blood vessels be widened to reduce peripheral resistance pharmacologically?
Antagonize the actions of vasoconstrictors (alpha-1 adrenoreceptor blockers like doxazosin, Calcium channel blockers such as nifedipine)
Increase the formation or prolong the action of vasodilating substances or their second messengers (e.g. nitric oxide donors)
Prevent the formation of endogenous vasoconstrictors (e.g. enzyme inhibitors)
How can blood volume be reduced pharmacologically?
Diuretics can be used to increase naturesis which helps the kidneys eliminate excess salt and water from the blood
e.g. Furosemide, bendroflumethiazide
How can pharmacological action be used to prevent further loss of compliance of blood vessels?
Statins and angiotensin converting enzyme inhibitors
What is prazosin?
An alpha-1 antagonist which is used to induce vasodilation
What is Captopril?
An ACE inhibitor which is used to induce vasodilation, diuresis and vascular remodelling
What is metaprolol?
A beta-1 antagonist used to decrease the rate and force of contraction (cardiac output) and to decrease renin production
What is nifedipine?
A ca2+ channel blocker which can induce vasodilation
What is frusemide?
A loop diuretic which inhibits Na reabsorption to decrease blood volume
What hypertension treatment is recommended for people who have raised or normal plasma renin levels?
An ACE inhibitor or an AT1 antagonist
What hypertension treatment is recommended for older people who are likely to have low plasma renin?
ACE inhibitor/Diuretic or ACE inhibitor/Ca2+ antagonist combination
