ACE Inhibitors Flashcards
(13 cards)
ACE Inhibitors
Block angiotensin converting enzyme (ACE) preventing conversion of angiotensin I to angiotensin II.
Angiotensin 2
a vasoconstrictor, acting directly on the kidney to increase sodium reabsorption in the proximal convoluted tubule to be reabsorbed by the sodium hydrogen exchanger.
It also promotes release of aldosterone.
Aldosterone
Stimulated by angiotensin 2
Salt and water retention by acting on distal convoluted tubule to increase epithelial sodium channels.
Increases activity of basolateral sodium-potassium ATP-ase → increases electrochemical gradient for movement of sodium ions into kidney.
Overall role of angiotensin 2
Promote aldosterone
Decreased water excretion and increased blood volume and pressure.
Vasoconstrictor.
Role of ACE
Convert angiotensin 1 to angiotensin 2
Breaks down bradykinin (responsible for vasodilation) so increases the constricting effect.
Uses of ACE inhibitors
HTN
HF
Kidney disease
How does ACE inhibitors help HTN
reduced blood volume and vasodilation resulting in reduced blood pressure
How do ACE inhibitors help HF
reduced water reabsorption and increased excretion. Reduced blood volume and vasodilation causing reduction in BP.
How do ACE inhibitors help kidney disease
Angiotensin II constricts the efferent glomerular arterioles
ACE inhibitors therefore lead to dilation of the efferent arterioles →
reduced glomerular capillary pressure → decreased mechanical stress on the delicate filtration barriers of the glomeruli.
S/E ACE Inhibitors
Dry, persistent cough due to increased bradykinin levels
Dizziness, fatigue and headache
Angioedema
Hyperkalaemia
Contraindications ACE inhibitors
Pregnancy - avoid
Less effective in afro-caribbean patients.
Aortic stenosis - hypotension
Monitoring ACE inhibitors
Urea and Electrolytes
Increase in creatinine, potassium
Examples of ACE inhibitors
Ramipril, Enalapril, Perindopril, Lisinopril.
