Hypertension - revision notes PDF

Preview

Summary

revision notes...

Description

Hypertension https://cks.nice.org.uk/topics/hypertension-not-diabetic/ [NICE guideline ref] Definition: Hypertension is persistently raised arterial blood pressure. It increases the risk of a number of conditions, including heart failure, coronary artery disease, stroke, chronic kidney disease, peripheral arterial disease, and vascular dementia. • Stage 1 hypertension: BP in surgery/clinic is >140/90mmHg and ambulatory blood pressure monitoring (24hr BP) or home blood pressure monitoring is >135/85 mmHg • Stage 2 hypertension: BP in surgery/clinic is >160/100 mmHg and ABPM or HBPM is >150/95 mmHg • Severe hypertension: BP in surgery/clinic is >180/110 mmHg or higher

Assessment: • Examination of the optic fundi (to check for retinopathy) • ECG to detect left ventricular hypertrophy • Check renal function • Determine CVD risk • Looking for target organ damage  Kidneys: urine dipstick test for protein and blood; serum creatinine and electrolytes and eGFR; renal ultrasound  Heart: 12 lead ECG (looking for LVH or CHD) and echocardiography • Cardiovascular disease prevention  Diabetes: check fasting blood glucose  Cholesterol: check fasting serum total and HDL cholesterol Treatment: Thiazide and thiazide-like diuretics  Bendroflumethiazide  Chlortalidone  Hydrochlorothiazide  Indapamide  Reduce blood pressure by reducing blood volume - in longer term reduce total peripheral resistance - direct vasodilatory action  Main class of diuretic used Loop diuretic  Furosemide  Only use in impaired renal function Potassium-sparing diuretic  Spironolactone  Aldosterone antagonist  Use in patients with resistant hypertension

Angiotensin converting enzyme (ACE) inhibitors  Ramipril  Enalapril  Lisinopril  Perindopril  Block the conversion of angiotensin I to angiotensin II  ACE inhibitors can cause persistent dry cough - switch to ARBs if this is the case  First dose and postural hypotension is likely  Monitor renal function, serum potassium and BP before starting and regularly during treatment  Monitor creatinine until required dosage is reached, and then every 6 to 12 months thereafter Angiotensin II receptor antagonists (ARBs)  Candesartan  Irbesartan  Losartan  Olmesartan  Block the action of angiotensin II at the type 2 receptor Renin antagonist  Aliskiren  Blocks the release of renin from juxtaglomerular cells so it is unavailable to cleave angiotensinogen into angiotensin I Beta blockers  Acebutolol  Atenolol  Bisoprolol  Blocks beta adrenoreceptors  Beta 1 receptors are mainly found in the heart and kidney. Beta 2 receptors are mainly found in the lungs and peripheral blood vessels  Heart - reduces heart rate and contractility  Kidneys - inhibits the release of renin,  Cardioselective but not specific (i.e. they work on the heart but work on both beta 1 and beta 2 receptors)  Bronchospasms - due to blockage of beta 2 receptors (warning in asthma patients)  Vasodilation of blood vessels can lead to cold hands and feet  Monitor for bradycardia  Masks hypoglycaemia in type 1 diabetes because it blunts SNS activation Alpha blockers  Doxazosin  Indoramin  Prazosin  Terazosin





Act selectively at post-ganglionic alpha1-receptors. Selective blockade of peripheral alpha1-receptors leads to vasodilatation and hence reduction in blood pressure Used as add-ons in difficult to treat hypertension or where other drugs are poorly tolerated Risk of first dose and postural hypotension

Centrally acting agents  Methyldopa   

Use is reducing due to unpleasant and harmful side effects The few drugs that are still used are for difficult to treat hypertension Methyldopa remains one of the few antihypertensive drugs that can be used in pregnancy along with labetalol (beta blocker)

Calcium channel blockers  Dihydropyridine derivates: o Amlodipine o Felodipine o Nifedipine o Phenylalkylamine: o Verapamil  Benzothiazepine derivative: o Diltiazem  Block slow calcium channels in the peripheral blood vessels and heart, promoting vasodilation  Verapamil and diltiazem are also vasodilators but the balance of actions is such that these drugs have noticeable cardiac effects (work on the heart ) including reduced heart rate (rate-limiting CCBs).  Long-acting dihydropyridine drugs, such as amlodipine in once-daily formulations are preferred  Dihydropyridines cause headache, flushing, swelling of ankles, gum hypertrophy  Verapamil can cause constipation Other agents for more resistant hypertension  Minoxidil  Hydralazine  Sodium nitroprusside Minoxidil- vasodilator, can cause reflex tachycardia and peripheral oedema-it causes hirsutism not suitable for women.  Hydralazine-profound vasodilator-SLE.  Sodium nitroprusside-direct acting arterial and venous dilator-IV-for hypertensive emergency and acute control of blood pressure during anaesthesia....