Cardio L16 Drug therapy 2 Hypertension Flashcards Preview

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Flashcards in Cardio L16 Drug therapy 2 Hypertension Deck (36)
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1
Q

Secondary Hypertension

aetiology

A
  1. Renal or renovascular disease
  2. Endocrine disease e.g.
    • Phaechomocytoma (tumour of arterial medulla)
    • Cushings syndrome (excess cortisol)
    • Conn’s Syndrome (excess aldosterone)
    • Acromegaly (excess growth hormone)
    • Hypo/hyper thyroidism
    • Pregnancy
  3. Co-arctation of the aorta
  4. Iatrogenic
    • Hormonal/ oral contraceptive
    • NSAIDs
2
Q

Typical feature of hypertensive heart disease

A

Left ventricle thickening

3
Q

Treatment: 7 example

A
  1. Thiazides
  2. Ca2+ channel blockers
  3. ACE inhibitors
  4. α 1-adrenoceptor blockers:
  5. Ang II receptor blockers:
  6. K+ channel activators:
  7. α –methyldopa:
4
Q

Thiazides

A

Class of diuretics control hypertension (in part) by blocking the Na+ - Cl_ symporter in first part of DCT.

5
Q

Thiazides function

A
  • Diuresis follows the increased NA load at CD
  • This increases K loss due to increased tubule Na and aldosterone – dependent Na+-K+ exchange.
  • Reduced Uric acid, Ma2+, Ca2+ excretion.
  • Note “thiazide” can also be used for drugs with similar action but not thiazide structure (e.g. chlorthalidone and metolazone).
6
Q

Thiazides Additional action

A

• Vasodilator action

7
Q

Thiazides Side effects

A
  • Electrolyte disturbances
  • Decrease glucose tolerance
  • Can reduce efficacy of anticoagulants and uriosurics
  • Can increase LDL and cholesterol
8
Q

Thiazides Examples

A
  • Hydrochlorothiazide

* Bendroflumethazide

9
Q

Ca2+ channel blockers function

A

Want to dilate periphery to:

  1. Reduce peripheral resistance
  2. Reduce filling pressure
10
Q

Ca2+ channel blockers examples

A
  1. Dihydropyridines →
    • Nifedipine
    • Amlodipine
11
Q

Ca2+ channel blockers side effects

A
  1. Peripheral oedema, dizziness

3. Generally contraindicated in HF, but non-DHP may be useful (e.g. verapamil) in such cases.

12
Q

ACE inhibitors: function

A

Long-term control of BP involves renin-angiotensin system.

13
Q

Angiotensin is

A

A vasoconstrictor

14
Q

Examples of prototypic drugs

A

Captopril

Enalapril

15
Q

Effects in 2 phases ACE inhibitors

A
  1. Rapid due to direct anti- ANG II effect

2. Slower due to blood volume effect and control of thirst.

16
Q

Side effects ACE inhibitors

A
  • Related to bradykinin (cough in 15%)
  • Hyperkalaemia
  • Taste disturbances
  • First dose hypotension
17
Q

α 1-adrenoceptor blockers:

A

Beta2 receptors dilate and alpha1 receptors constrict vascular smooth muscle

18
Q

α 1-adrenoceptor blockers: example

A

Prazosin
Doxazosin
Function → antagonise noradrenaline

19
Q

α 1-adrenoceptor blockers: side effects

A

Headache
Nausea
Hypotension
Auto-immune problems

20
Q

Alpha 1 receptor

A

Noradrenaline >adrenaline

21
Q

Beta 2 receptor

A

Adrenaline&raquo_space; noradrenaline

22
Q

Alpha1 adrenoceptors work via

A
G alpha induces 
PLC which induces
IP3 and DAG leads to
SR Ca release
CaM
MLCK
Muscle contraction
23
Q

Angiotensin II leads to:

A
  1. Na, water retention

2. Thirst

24
Q

Angiotensin II antagonists function

A

Block the AT1 receptor and are the most modern approach to limit blood volume expansion (good for CHF and hypertension)

25
Q

Protective in (Angiotensin II blcokers)

A

Diabetic nephropathy

26
Q

Ang II receptor blockers: Side effects

A

Hyperkalaemia
Diarrhea
Dizziness
Tiredness

27
Q

Ang II receptor blockers: Example

A

Losartan

28
Q

K+ channel activators: Act to

A

Calcium entry into SM cells depends on Vm

• Both L-type channels and NCX Ca entry inhibited by hyperpolarization.

29
Q

K+ channel activators: Example and function

A

Minoxidil
Pinacidil
→ Increase permeability to K+ thereby hyperpolarizing SM cell

30
Q

K+ channel activators: Side effects

A

Generally well tolerated
Fluid retention
May worsen angina
Hirsuitism

31
Q

α –methyldopa: action

A

This pro-drug is converted to methyl-noradrenaline

  1. Not metabolized by MAO
  2. Displaces noradrenaline in synaptic vesicles
  3. Reduces renin secretion (hence ANG II levels)
32
Q

α –methyldopa: used for

A

Hypertension that does not respond to other (more modern) treatment regimens e.g. severe pre-eclampsia.

33
Q

Ganglion blockers: examples

A

Guanethidine

Guanadrel

34
Q

Ganglion blockers: function

A

Target peripheral adrenergic neuron

35
Q

Ganglion blockers: Uptake leads to

A

Guandrel substituting for noradrenaline in secretory granules reducing sympathetic neurotransmission.

36
Q

Ganglion blockers: used for

A

Uncontrollable hypertension

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