ELM9: Hypertension 2 Flashcards
How many types of calcium channel blockers are there?
5
Which calcium channel blocker is commonly used to treat hypertension?
L type
What is the process of calcium channel blockers being used in hypertension?
- Reduce opening of L type calcium channels
- Target organs are vasculature and heart
- Vessels inhibit calcium entry
- Heart has reduced contractility
What are some side effects of using calcium channel blockers to treat hypertension?
Headache and constipation
What is resistance?
Determined by diameter of resistance vessels like arterioles
How can drugs be used to control resistance?
Arterioles have smooth muscle triggered to contract by SNS
Drugs can interact with SNS to contract them
How does noradrenaline interact with calcium concentration and cause contraction?
- Acts on alpha 1 adrenoceptors to activate PLC
- IP3 release which increases calcium concentration
- Ca sensitive chlorine channels open and cl leaves cell
- Depolarisation
- L type calcium channels open and calcium enters
- Contraction
What is the action as part of the noradrenaline pathway are calcium channel blockers trying to prevent?
Opening of L type calcium channels in response to depolarisation
What is the role of the renin-angiotensin aldosterone system?
Slow control of blood pressure
Which cells secrete renin?
Cells of juxtaglomerular apparatus
What stimulates the production of renin?
Adrenaline
Prostacyclins
Decreased sodium in distal tube
Decrease in blood pressure in kidney
Where is renin secreted into?
Circulation
Where is angiotensin produced and secreted?
Produced in liver
Secreted in circulation
What are the two drug types that act on the RAAS?
ACE inhibitors
ARBs
What is an example of a renin inhibitor?
Aliskiren
What are some side effects of aliskiren?
Kidney problems
Stroke
Hypertension
What is the role of ACE inhibitors?
Prevents the formation of angiotensin I into II
Reduces aldosterone production and vasodilation as there is no active angiotensin
What are some examples of ACE inhibitors?
Captopril
Lisinopril
What are some side effects of ACE inhibitors?
Initial dose hypotension
Cough
What does the angiotensin II type 1 receptor do?
Vascular effects
Aldosterone release
What does the angiotensin II type 2 receptor do?
Growth and development
What is the role of angiotensin II antagonists? (ARBs)
Treat hypertension
What are some examples of ARBs?
Losartan
Candesartan
What are some side effects of ARBs?
Hypotension but no cough
What are some other clinical uses of ACEs and ARBs?
In heart failure
After heart attack
What is a diuretic?
Causes increased urine output
How do diuretics work to treat hypertension?
- Increase urine output
- Decrease in intravascular salt and water concentration
- Lower blood pressure
What are the three main types of diuretics?
Loop
Thiazide
Potassium sparing
What are loop diuretics?
Water cannot be absorbed from descending limb and only happens in ascending
Water loss in ascending driven by sodium loss If this is blocked there is less water lost from the urine
What are the main examples of loop diuretics?
Furosemide
Bumetanide
How do the two main loop diuretics work?
Inhibit the sodium potassium chloride cotransporter in ascending limb of loop of Henle
What are the clinical uses of loop diuretics?
Heart failure
Pulmonary oedema
Renal failure
How do thiazide diuretics work?
Inhibit sodium chloride cotransport in distal convoluted tubule
Reduced ability in distal segments to absorb water
What are some examples of thiazide diuretics?
Bendoflymethiazide
Chlortalidone
What are some clinical uses of thiazide diuretics?
Oedema
Hypertension
What are potassium sparing diuretics?
Decrease trans-principal cell sodium movement
Decrease negative lumen potential
What are some examples of potassium sparing diuretics?
Spironolactone an aldosterone antagonist
Amiloride
What is doxazosin?
Dilates veins and arterioles by blocking alpha 1 adrenoreceptors
What are some side effects of doxazosin?
Postural hypotension
Urinary incontinence
Retrograde ejaculation
What is propanolol?
Competitive antagonist at beta receptors
Lipid soluble
Best penetration of blood brain barrier
What are atenolol and bisopropolol?
Competitive antagonists of beta receptors
Selective
B is the most selective
A is worst penetration of blood brain barrier
What are some side effects of beta andrenoceptor antagonists?
Bronchoconstriction
Cold extremities
Glucose control
Vivid dreams
