Drug Treatment for Cardiovascular Disease Flashcards
b receptors molecular action
Gs-protein dependent activation of AC –> increases cAMP –> activates pKA –> increases/decreases intracellular calcium –> increases contractility of cardiac muscle and decreases the contractility of arterial smooth muscle and bronchial smooth muscle
examples of beta blocker drug and their indications
propnol- non selective beta blocker- effective for angina, HTN, arrhthymias, migraine, tremor
bisoprolol-commonly in the UK- selective b1 blocker
heart: decreases force and rate of contraction-> reduces BP
lungs: bronchoconstriction
arterioles: decreases blood supply to muscles, skin, penis
side effects of beta blockers
heart: fatigue, bradycardia
lungs: breathlessness, exacerbations of asthma
arterioles: fatigue, claudication, cold hands/feet, erectile dysfunction
contraindication of beta blockers
hypoglycaemia and beta blockers
- low blood glucose activates Adr release (mobilises glucose from the liver-gluconeogenesis)
- causes tremor, palpitations, sweat
- symptoms blocked by beta blockers
- patients need to be able to recognise hypoglycaemia
- beta blockers contraindicated in diabetic pts with recurrent hypoglycaemia
Mechanism of action of thiazide diuretics
BENDROFLUMETHIAZIDE-blocks Na+/Cl- symporter on the lumenal side of the epithelial cells
-inhibits reabsorption of Na and Cl and increases excretion of Na+/Cl- and water which lowers BP
INDAPAMIDE-arterioles (K-ATP): decreases BP
side effects of thiazides
kidney: hyponatraemia, hypokalaemia, alkalosis, hypercalcaemia, hypermagnesaemia, increase in urate
insulin resistance: increase in glucose (diabetes)
liver: increase in lipids (arterial disease)
other indications of thiazide diuretics
oedema, UT stones, nephrogenic diabetes insipidus
core thiazide drug
bendroflumethiazide
alpha blockers mechanism of action
a1 receptors acts via the Gq protein to increase IPA levels and further release of Ca2+ from the sarcoplasmic reticulum
a-blocker drug
doxazosin- decreases Ca2+ release in arteriolar smooth muscle
other indications of a-blockers
prostatic hypertrophy to relax bladder outflow sphincter
side effects of alpha blockers
palpitations (reflex tachycardia), postural hypotension
calcium channel blocker mechanism of action
- blocks the L-type voltage gates Ca2+ channel
- decreases intracellular Ca2+
- arterioles: smooth muscle relaxation
- heart: decreased force of contraction
- SA and AV node: decreased heart rate
other indications of calcium channel blocker
Raynaud’s syndrome, angina, arrhythmias
core calcium channel blockers
amlodipine, ditiazem, verapamil
side effects of calcium channel blockers
preferential dilation of pre-capillary arteriole -impaired function of the capillary sphincter -increased hydrostatic pressure -net filtration -palpitations (reflex tachycardia) -constipation -flushing -headache -exacerbation of HF (D&V)
ACE inhibitor mechanism of action
ACE converts AngI to AngII. ACE breaksdown Bradykinin (vasoactive peptide) -> ACE-Inhibitors decrease Ang-II production and increases bradykinin breakdown
core ACE inhibitor
rampiril
side effects of ACE inhibitors
dry cough (accumulation of bradykinin in lungs- bronchial irritation), renal impariment- esp with renal artery stenosis, hyperkalaemia- commonly given with diuretic
other indications of ACE inhibitors
HF
aldosterone antagonist mechanism of action
-blocks the upregulation of sodium channels in the DCT by aldosterone
core aldosterone antagonist
Spironolactone- usually used as an add on in resistant HTN
other indication of aldosterone antagonist
hyperaldosteronism
spironolactone side effects
impaired renal function, hyperkalaemia, gynaecomastia (oestrogen-androgen imbalance)
Ang-II receptor antagonists mechanism of action
blocks action of AT-II on the AT receptor, similar physiological effects to ACE-I’s
side effects of AR antagonists
similar side effect profile to placebo, does not cause dry cough like ACE-I’s
core AR antagonist
losartan
stage 1 BP according to NICE guidance
BP>140/90mmHg- treat if end-organ damage or diabetic
stage 2 BP according to NICE guidance
BP>160/100mmHg- treat once confirmed on 24 hr reading
stage 3 BP according to NICE guidance
Systolic BP >180 mmHg- treat immediately
lifestyle management in HTN
decrease weight, decrease salt intake, decrease alcohol intake, increase exercise
treatment targets for age and diabetics as per NICE
age less than 80=140/90
age more than 80= 150/90
diabetics= 135/85
NICE treatment for hypertension for people younger than 55 and assume patient not of black ethinicity
- ACE-I or AR2B
- ACE-I+ Ca2+ channel blocker OR ACE-I + thiazide diuretic
- ACE-I+ Ca2+ channel blocker+thiazide diuretic
- Add a further diuretic, a-blocker, beta blocker. consider specialist advice
NICE treatment for hypertension for people older than 55 or of black ethinicity
- Ca2+ channel blocker OR Thiazide diuretic
- ACE-I+ Ca2+ channel blocker OR ACE-I + thiazide diuretic
- ACE-I+ Ca2+ channel blocker+thiazide diuretic
- Add a further diuretic, a-blocker, beta blocker. consider specialist advice
