Pharmacology of HTN 1

Cards (30)

  • What is isolated systolic HTN?
    Systolic > 140
    Diastolic < 90
    High pulse pressure
    Most common
  • What is isolated diastolic HTN?
    Systolic < 140
    Diastolic > 90
    Least common
  • What is mixed HTN?
    Systolic > 140
    Diastolic > 90
  • What is the percentage of each HTN?
    Essential HTN > 90%
    Secondary HTN < 10%
  • What is essential HTN?
    Idiopathic HTN (no clear causative factor)
  • What is secondary HTN?
    High blood pressure that is caused by an underlying medical condition or medication
    • renal disorders
    • endocrine disorders (primary hyperaldosteronism, phaechromocytoma, Cushing's syndrome)
    • drug-induced (abuse (cocaine), iatrogenic (combined oral contraceptive, glucocorticoids))
    • pregnancy - pre-eclampsia
  • What are the consequences of HTN?
    Increased risk of many CV disorders (stroke, heart failure, peripheral arterial disease, CKD etc.)
  • What are the mechanisms that underlie HTN?
    Cardiac output
    Peripheral resistance
    Autonomic NS
    Endothelium
    Vasoactive peptides
    RAAS
  • Arterial BP = CO x TPR
  • CO = SV x HR
  • How does the autonomic NS impact HTN?
    Heart - b1 receptor -> increases HR -> increased CO
    Vessels - a1 receptor -> vasoconstriction, b2 receptor -> vasodilation
    Short-term regulation (e.g. baroreceptor reflex)
  • What do endothelial cells produce?
    Vasoactive agents (NO, PGI2, endothelin)
  • What is the effect of NO?
    Vasodilation
    by binding to guanylyl cyclase -> increase cGMP -> increase PKG -> smooth muscle relaxation
  • What does prostacyclin (PGI1) do?
    Vasodilation
  • What does enothelin do?
    Vasoconstriction
  • Give 3 examples of vasoactive peptides.
    Bradykinin
    Natriuretic peptides (A, B & C)
    Vasopressin (ADH)
  • What is the effect of bradykinin?
    Vasodilation
    ACE inhibtors block bradykinin inactivation
  • What is the effect of vasopressin (ADH)?
    Vasoconstriction
  • What is renin produced by?
    Juxtaglomerular cells
  • RAAS is a target for many important & effective drugs used to treat HTN.
  • What is Liddle syndrome?
    Rare autosomal dominant disorder that causes severe HTN at an early age
    Caused by mutations in beta & gamma subunits of ENaCs -> prevents channel internalisation & degradation -> overexpression of ENaCs -> excess Na+ reabsorption
  • What is the treatment of Liddle syndrome?

    ENaC channel blockers (e.g. amiloride)
  • Fill in the blanks
    A) peptides
    B) receptors
    C) AT-II
    D) AT1
  • Different classes of drugs used to treat HTN?
    Diuretics
    Renin inhibitor (-kiren)
    ACE inhibitor (-pril)
    Angiotensin Receptor Blocker (ARB) (-sartan)
    Ca+2 channel blocker (-dipine)
    Beta blockers (-lol)
    Centrally acting a2 agonists
    Vasodilators
  • What is Stage 1 HTN?
    140/90 < ABP < 159/99
  • What is Stage 2 HTN?
    160/100 < ABP < 180/120
  • What is Stage 3 HTN?
    SBP > 180 OR DBP > 120
  • What do natriuretic peptides do?
    Increase Na+ & water excretion (in urine)
  • What is hexamethonium?
    Analogue of ACh
    Target: nicotinic receptor
    Activity: channel blocker
    Blocks sympathetic & parasympathetic NS
  • What are the functions of voltage-gated Ca+2 channels?
    Cardiac AP/pacemaker
    Smooth/skeletal muscle contraction
    Endocrine (e.g. insulin secretion)
    Ntr release