Hypertension Flashcards
Diuretic potency of loop diuretics
High - loss of fluid can be dramatic
Anti hypertensive effect of loop diuretics
No more effective than thiazides at reducing BP
Clinical use of loop diuretics
Reserved for patients with pulmonary oedema, heart failure, renal insufficiency, resistant hypertension
Reduces oedema
Daily oral tablet but IV transfusion gives rapid effect
Side effects of loop diuretics
Excessive loss of Sodium and water resulting in hypovolaemia and hypotension
Potassium loss resulting in hypokalaemia
Metabolic alkalosis
Examples of loop diuretics
Furosemide
Bumetanide
Terasemide
Diuretic potency of thiazide diuretics
Moderate
Anti hypertensive effect of thiazide diuretics
Reduce systolic and diastolic pressure in hypertensive patients and risk of cardiovascular complications
Have additional vasodilator action: BP falls initially due to renal action, reduced blood volume stimulates renal secretion and limits effect on BP, vasodilation maintains antihypertensive effect
Clinical use of thiazide diuretics
Usually given as an add on if drugs not sufficient on own
Thiazides potentials effects of other hypertensive drugs
Daily oral tablet
Thiazide side effects
Safe drugs
More frequent urination
Hypokalaemia
Erectile dysfunction (could relate to vasodilator action)
Examples of (original) thiazide drugs
Chlorothiazide
Hydrochlorothiazide
Bendroflumethiazide
Examples of (newer thiazide-like - same action) thiazide drugs
Indapamide (preferred)
Chlorthalidone (preferred)
Metolazone
Diuretic potency of aldosterone antagonists
Weak
Anti hypertensive effect of aldosterone antagonists
Marked anti hypertensive effect
Spieonolactone prolonged syrvival in patients with heart failure
Clinical use of aldosterone antagonists
Used in treatment of heart failure, hyperaldosteronism, resistant hypertension (esp. with low renin)
Prevents hypokalaemia when given with loop or thiazide diuretic
Daily oral tablet
Side effects of aldosterone antagonist
Potentially fatal hyperkalaemia
GI upset
Gynaecomastia, menstrual disorders and testicular atrophy due to actions at other steroid receptors
Examples of aldosterone antagonist
Spironolactone
Eplerenone
Side effects of all diuretics
Disturb plasma electrolyte balance (potassium a particular concern)
Loss of renal function as consequence of hypovolaemia
Therefore serum electrolyte and creatinine levels monitored
Dihydropyridines (calcium antagonist) examples
Amlodipine
Felodipine
Nimodipine
Dihydropyridines (calcium antagonist) cardiovascular selectivity
Smooth muscle selective
Inhibit calcium channels in vascular smooth muscle with little effect on heart
Nimodipine acts preferentially on cerebral arteries
Therapeutic use of Dihydropyridines (calcium antagonist)
First line anti hypertensive drugs
Nimodipine used for vasospasm after cerebral haemorrhage
Phenylalkylamines (calcium antagonsist) example
Verapamil
Phenylalkylamines (calcium antagonist) cardiovascular selectivity
Cardiac selective
At doses inhibiting cardiac channels, little effect on smooth muscle
Phenylalkylamines (calcium antagonist) therapeutic use
Used to treat cardiac arythmias and angina
Benzothiazepines (calcium antagonist) example
Diltiazem
