Hypertension Flashcards
Define Hypertension
Increased blood pressure of greater than 140/90mmHg. BP = Cardiac Output × Peripheral Vascular Resistance.
What is meant by systolic and diastolic blood pressure?
Systolic is the peak pressure in the arteries during ventricular contraction.
Diastolic is the pressure in the arteries when the chambers are filling.
What is the difference between hypertensive emergency and urgency?
Hypertensive urgency is a BP of 180/120 without progressing end-organ damage.
Hypertensive emergency is a BP of 180/120 with acute end-organ damage.
What is Renin?
It is an enzyme stored in the juxtaglomerular cells in renal afferent arterioles. Renin is released by decreased renal blood flow or low salt delivered to the TAL and catecholamines.
What are some effects of angiotensin II effects?
Cause vasoconstriction. Increase PVR.
Stimulate NA and Adrenaline from the adrenal cortex. Stimulates vasopressin.
Stimulates aldosterone synthesis. This increases sodium and water reabsorption from the kidney. Increases plasma volume and PVR.
What is a natriuretic hormone and what is its function?
Atrial natriuretic peptide. It increases GFR, inhibits sodium and H2O reabsorption. Functional antagonist of RAAS. Also causes smooth muscle cell relaxation and increased endothelial permeability.
What are the neuronal regulations of BP?
Stimulation of post-synaptic Rs - alpha 1 Rs on arterioles and venules cause vasoconstriction. Beta 1 Rs in the heart - increase HR and force of contraction.
B2 Rs in arteries and veins - vasodilation.
Stimulation of pre-synaptic Rs -
A2 Rs - inhibition of NA release. B2 Rs - facilitate NA release.
Baroreceptors, found in the carotid arteries and aortic arch. An increase in BP increases the firing of baroreceptors. Decreases heart rate, vasoconstriction and sympathetic outflow.
What is the MoA of Thiazide diuretics and its indications?
Inhibit reasborption of Na and Cl by inhibiting the transporter on the luminal membrane of the DCT. Used for hypertension (first-line) in black patients and oedema.
What are some side effects of thiazides?
Hypokalaemia, Hypercalcaemia and C/I in Gout and severe hepatic and renal failure.
List 4 drug interactions of thiazides.
Lithium, NSAIDs, Digoxin and Beta blockers and antidiabetic drugs.
What is the MoA of Loop diuretics
Inhibit reabsorption of Na and Cl by competing with CL ions for binding to Na/K2Cl cotransporter on the atypical membrane in the TAL of Henle.
What are some pharmacokinetics of loop diuretics?
Rapidly absorbed. Onset of action, within 20-60 mins. Secretion due to high PPB. Hepatic metabolism.
What are some indications of K sparing diuretics?
Spironolactone, eplerenone and amiloride is for resistant hypertension, primary hyperaldosteronism and Oedema.
What is the MoA of ACEIs?
They inhibit ACE, which inhibits the conversion of angiotensin I to angiotensin II. Decreases vasoconstriction and aldosterone release. This will also reduce the breakdown of bradykinin leading to vasodilation leading to decreasing PVR.
What are C/Is of ACEIs?
Pregnancy, history of angio-oedema, hyperkalaemia, renal artery stenosis.