Hypertension Flashcards
Secondary hypertension may be due to:
- renal disease
- renovascular disease
- Conn’s syndrome
- Cushing’s syndrome
- hyperthyroidism
- phaeochromocytoma
- pregnancy
- Drugs ( e.g. NSAIDs, corticosteroids, venlafaxine, ciclosporin, sympathomimetics)
NICE treatment target
SBP <140mmHg
DBP <90mmHg (80 in diabetes)
Specific goals
- Reduction in cardiovascular damage
- Preservation of renal function
- Limitation or reveresal of LVH
- Prevention of IHD
- Reduction in mortality due to stroke and MIs
Mechanism behind ACEI
inhibit ACE, lead to reductions in angiotensin II, which leads to:
- Reductions in arterial and venous vasoconstriction
- Reduced aldosterone production leads to reductions in salt and water retention
- Also potentiate bradykinin –> cough
Contraindications and side-effects of ACEIs
Should be avoided in renovascular disease
- Renin-dependent 20 hypertension, ACEIs lead to renal underperfusion and severe hypotension
- May lead to worsening of renal function; discontinue
- Monitor creatine before and during use
- Paradoxically ACEIs are effective at the prevention of nephropathy in DM and may be agents of choice in pts with diabetes.
- May increase potassium – interaction with salt (KCl) substitute
Angioedema
ACEI examples
- captopril
- enalapril
- lisinopril
- perindopril
- ramipril
Mechanism of AT1 receptor antagonists + examples
Block the action of AII at the AT1 receptor.
- similar consequences as ACEIs but no cough
- Candesartan, losartan, valsartan
Types of vasodilators used in hypertension
Calcium channel blockers
Alpha-blockers
Calcium channel blockers for hypertension
- Inhibit voltage operated calcium channels on vascular smooth muscle, leading to vasodilatation and a reduction in BP
- Verapamil acts mainly heart compared with dihydropyridine effects, which are greater on arteriole smooth muscle
- e.g. diltiazem, verapamil & dihydropyridines (amlodipine, felodipine, nifedipine)
Alpha-blockers in hypertension
e.g. doxazosin, prazosin
- These are competitive receptor antagonists of a1-adrenoceptors
- Last choice antihypertensives
- Widespread side effects, which makes them poorly tolerated
MOA/Side-effects of diuretics for hypertension
Thiazide-like e.g. chlortalidone and indapamide
Thiazides (e.g. bendroflumethiazide)
- THIRD line antihypertensives
- Inhibit Na+/Cl- in distal convoluted tubule
- Reduction in circulating volume
- Also causes vasodilatation
- Ineffective in moderate renal impairment (except metolazone)
- Measure renal function (creatinine) before and during use
Important side effects
- Hypokalaemia
- Postural hypotension
- Impaired glucose control
- Do not use in gout
Beta-blockers in hypertension and CIs
no longer recommended as first line (due to reduced effectiveness at preventing stroke and increased risk of diabetes)
e.g. atenolol (most common), propranolol
- Reduction in sympathetic drive to the heart, reducing cardiac output
- A reduction in sympathetically evoked renin release
Beta-blockers (even b1 selective agents) may block bronchial b2 receptors and are contraindicated in asthma and caution in COPD
Adveres effects of ACEIs
- Cough
- Severe first dose hypotension
- Renal damage?
Adverse effects of Calcium channel blockers
- Peripheral oedema
- Postural hypotension
- Constipation (some)
Adverse effects of Thiazides
- Urination
- Diabetogenic
- Alter lipid profile
- Hypokalaemia
- Impotence?
- Postural hypotension
Adverse effects of beta-blockers
- Bronchospasm
- Reduce hypoglycaemic awareness
ACD rules
