Anti-hypertensives Flashcards
What are the 2 types of hypertension?
Essential (no obvious cause)
Secondary (kidney disease, tumours)
What 2 physiological components determines MAP (mean arterial pressure)?
C.O (Stroke volume x heart rate)
Peripheral resistance
Over time, C.O normalises and peripheral resistance increases.
What can we do to lower hypertension?
Lower C.O and peripheral resistance.
Target SNS
Renin-angiotensin-aldosterone system
Target blood vessels
Treatment goals and possible therapies?
Reduce heart rate - B1 receptor antagonists. Widen blood vessels (vasodilators) Reduce blood volume Reduce viscosity of blood Prevent loss of further compliance.
RAA system has what 3 components?
Renin - primarily released by juxtaglomerular cells of kidney.
This stimulates formation of angiotensin in blood and tissues.
This stimulates release of aldosterone from adrenal cortex.
What does renin do?
Converts angiotensinogen into angiotensin I.
What does ACE do?
converts ANGI to ANGII
What is renin release controlled by?
Changes in arterial pressure Renal sympathetic nerve activity Glomerular filtration B agonists and PGI2 stimulate renin release directly. ANP inhibits renin release.
ANG II causes what?
Vascular growth
Vasoconstriction
Salt retention
Are ACE and AT1 major drug targets for hypertension?
YES! :D
What is the recommended approach for treating people who have raised or normal plasma renin?
ACE inhibitor or AT1 antagonist
What is the recommended approach for treating older people who have likely to have low plasma renin?
ACE inhibitor/diuretic or ACE inhibitor/Ca2+ antagonist combo.
Out of B-blockers, ACE inhibitors and AT1 antagonists, which is less tolerated?
B-blockers
What is methyldopa used for?
Hypertension during pregnancy.
What drug acts on the ACE enzyme?
Captopril
