Drugs affecting cardiovascular system (blood pressure) Flashcards Preview

Cardiovascular & Respiratory Pharmacology (Karen) > Drugs affecting cardiovascular system (blood pressure) > Flashcards

Flashcards in Drugs affecting cardiovascular system (blood pressure) Deck (33)
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1
Q

High blood pressure is

A

140/90mmHg

130/80mmHg in diabetics, kidney disease

2
Q

Chronic BP >140/90mmHg is a risk factor for

A
  • Stroke
  • TIA
  • MI
  • Ischaemic heart disease
  • CHF
  • Aortic aneurism
  • Retinal Haemorrhage
  • Renal failure
  • Death
3
Q

BP =

A

CO x TPR

4
Q

CO =

A

HR x SV

5
Q

What is the major neuronal influence on BP?

A

Sympathetic tone: releases NA

-P = +SNS tone

6
Q

How does NA influence BP at the blood vessels?

A
  • activate A1-aR –> vasoconstriction
7
Q

How does NA affect BP at the heart?

A
  • activates B1-aR, +HR through SA and +contractility through ventricular muscle
8
Q

How does NA affect BP at the kidneys?

A
  • B1-aR: +Renin release
  • Angiotensinogin –> Ang1 –>
  • Angiotensin converting enzyme –> AngII
  • AngII acts on kidney, heart, and blood vessels
  • AngII +fbk to SNS to +BP
  • AngII important in remodelling in heart failure
9
Q

What are the antihypertensive drug classes?

(ABCD)

A
  • Angiotensin system inhibitors (BV, heart, kidney)
  • B-aR antagonists (kidney, heart)
  • Ca2+ channel blockers (BV, heart)
  • Diuretics (kidney)
  • (other)
10
Q

Aldosterone

A
  • Steroid hormone, adrenal cortex
  • Rl by angiotensin 1 receptors in kidney
  • Causes salt and water retention
  • tf +blood volume, +CO, +SV
11
Q

What are the targets for angiotensin system inhibitors?

A

Angtiotensin converting enzyme (ACE)

AT1 receptrors (vasoconstriction, aldosterone stimulation)

12
Q

What are -pril drugs?

A

Angiotensin converting enzyme inhibitors

e.g. captopril, enalapril, perindopril, ramipril

13
Q

What is the mechanism of angiotensin converting enzyme inhibitors?

A

‘-prils’

  • block Ang I –> Ang II tf -vascular tone, -aldosterone, -cardiac hypertrophy
  • preven bradykinin (vasodilator) breakdown
14
Q

What are the adverse effects of angiotensin converting enzyme inhibitors?

A
  • First-dose hypotension (must taper dose)
  • Dry cough
  • Loss of taste (bradykinin?)
  • Hyperkalaemia (+K+ in plasma)
  • Acute renal failure
  • Itching
  • Rash
  • Angio-oedema
  • Foetal malformations
15
Q

What must usually be prescribed with a ‘-pril’ and/or a ‘-sartan’?

A

A thiazide diuretic to combat hyperkalaemia (+K+ in plasma)

16
Q

What are the contraindications for ‘-pril’ drugs?

A
  • Pregnancy
  • Bilateral renal stenosis
  • Angioneurotic oedema
17
Q

What type of drugs are ‘-sartan’?

A

Angiotensin receptor antagonists

e.g. losartan, candesartan

18
Q

What are the contraindications for angiotensin receptor antagonists?

A

Same as for angiotensin converting enzyme inhibitors:

  • Pregnancy
  • Bilateral renal stenosis
  • Angioneurotic oedema
19
Q

What is the mechanism of angiotensin receptor antagonists?

A

‘-sartan’

  • Block AT1 receptor subtype (not known what AT2 does) to:
  • Reduce vasoconstriction
  • Reduce aldosterone
  • Reduce cardiac hypertrophy
  • *Reduce SNS activity
20
Q

What are the adverse effects of ‘-sartan’ drugs?

A

Angiotensin receptor antagonists

  • Hyperkalaemia (Tx thiazide diuretic)
  • Headache
  • Dizziness
21
Q

What type of drug are the ‘-olol’s?

A

B-aR antagonists

e.g. propranalol, atenolol, pindolol, timolol, metoprolol

22
Q

What is the mechanism of B-aR antagonists?

A

‘-olol’

  • reduce CO (initially), BP stays down
  • decreased rate, contractility
  • reduce renin release
  • LT effects on TPR, blood volume
23
Q

What is the selectivity of B-aR antagonists?

A

Beta-1: heart and kidney

Beta-2: vascular smooth muscle, airway smooth muscle

24
Q

What is sympathomimetic activity?

A

Mimics transmitters of the SNS e.g. catecholamines, adrenaline, noradrenaline, dopamine

These drugs are used to treat cardiac arrest and hypotension

25
Q

What are the adverse effects of B-aR antagonists?

A
  • Cold extremities (a1 constrictiors, block of b2 dilators)
  • Fatigue (b1 block reduced CO/HR, b2 block constricts skeletal muscle vessels, -O2)
  • hypoglycaemia
  • Dreams, insomnia (CNS effects, related to lipid solubility)
  • Bronchoconstriction (b2 blockade in airway smooth muscle)
26
Q

Why are B-aR antagonists contraindicated in diabetics?

A

B1 blockade reduces cardiac response tf it cannot +HR to +flow. Leads to drop in blood sugar

HR is an indicator of sugar levels

27
Q

Why are B-aR antagonists contraindicated in asthma?

A

Bronchoconstriction by the B2 blockade stopping the relaxation of airway smooth muscle

28
Q

How are beta blockers used in heart failure?

A

Reduce high sympathetic drive

29
Q

What are the contraindications of beta blockers?

A
  • Asthma
  • Diabetes
  • AV block

Care with:

  • Heart failure (can be good or bad)
  • Metabolic syndrome (men may develop diabetes)
30
Q

What is the mechanism of Ca2+ channel blockers?

A
  • Inhibit voltage-gated L-type Ca2+ channels in myocardium and vasculature
  • reduce cardiac/vascular contractility
  • reduce vascular resistance
31
Q

Dihydropyridines

A
  • Ca2+ channel blockers
  • selective to vasculature
  • increase HR
  • use in hypertension tx
  • contra if tachyarrhythmias present
  • adverse affects include oedema, flushing, headache, and reflex tachycardia
  • e.g. felodipine, nifedipine
32
Q

Verapamil

Diltiazem

A
  • Ca2+ channel blockers
  • non-selective
  • cause brady cardia
  • adverse: oedema, flushing headache
  • contra in heart failure
  • tx in tachy
33
Q

Thiazide diuretics

A
  • Prescribed with ACEI and AT receptor antagonists
  • combat hyperkalaemia (K+ retention)