hypertension Flashcards
What is hypertension
Raised blood pressure
List some consequences of hypertension
- Risk factor for cardiovascular problems
- Myocardial infarction
- Renal failure
- Heart failure due to left ventricular hypertrophy
- Left ventricular dysfunction
List some pathological changes linked with hypertension
- Thickening of the blood vessels walls
- Atherosclerosis
- Aneurysm formation
What can aneurysms and arterial wall thickening affect
Small arteries and arterioles and fibrinoid necrosis of the arteriolar wall
Why does hypertrophy of the left ventricle occur in hypertension
Due to increased pressure load on the myocardium and pathological changes in the renal glomeruli can also be seen
What can severe hypertension present as
- Visual disturbanves
- Headaches
- Changes in in mental function
- Impaired consciousness
5.Fits and florid retinal changes (swelling of optic nerve)
Guidelines state we should treat patients with a blood pressure grater than what
Greater than 160/100 mmHg
What blood pressure do we aim to get hypertensive patients
140/85mmHg
Give examples of lifestyle choices that can increase risk of hypertension
- High salt intake
- Alcohol excess
Give examples of causes of secondary hypertension
- Renal diseases including renal artery stenosis and polycystic kidneys
- Cushing’s syndrome (cortisol excess, including steroid treatment)
- Conn’s syndrome (aldosterone excess)
- Phaeochromocytoma (catecholamine excess)
- Acromegaly
- Hyperparathyroidism
- Coarctation of the aorta
- Drugs including oral contraceptives and monoamine oxidase
inhibitors
Give examples of drugs used to treat hypertension
- Diuretics
- Angiotensin-converting enzyme (ACE) inhibitors 3. Angiotensin II receptor antagonists (ARBs)
- Calcium channel blockers
- β-Adrenoreceptor antagonists (β-blockers)
- α-Adrenoreceptor blockers
- Vasodilators
- Centrally acting drugs.
What are diuretics classified into:
- Thiazides, e.g. bendroflumethiazide
- Loop, e.g. furosemide and bumetanide
- Potassium-sparing, e.g. amiloride
- Osmotic, e.g. mannitol
- Aldosterone antagonists including spironolactone
and eplerenone.
Describe the mechanism of action of diuretics
Decrease reabsorption of sodium in the kidneys
this rise in excretion of sodium causes a greater loss of water which results in a drop in plasma volume
all diuretics do this apart from osmotic diuretics
Describe the mechanism of action for osmotic diuretics
Osmotic diuretics interfere with water reabsorption but they are not used for the management of hypertension.
Give examples of side effects of diuretics
Dry mouth
Thiazide diuretics may produce lichenoid reactions and Stevens–Johnson syndrome.
Give examples of interactions diuretics can have in the dental setting
- Thiazides and loop diuretics result in potassium loss, and exacerbate the hypokalaemia produced by adrena- line in dental local anaesthetic solutions. not a concern in low doses
- Aspirin reduces the action of spironolactone and acetazolamide.
Give examples of ACE inhibitors
captopril,
enalapril,
lisinopril,
perindopril
ramipril.
Describe the mechanism of action of ACE inhibitors
ACE inhibitors exert their antihypertensive action by inhibiting the production of angiotensin II which stimulates aldoestone which is important in fluid balance
ACE inhibitors prevent the breakdown of bradykinin, which mediates certain allergic reactions.
As bradykinin is a vasodilator, this action contributes to the antihypertensive action of ACE inhibitors.
Give examples of side effects caused by ACE inhibitors
- Dry cough
- Dry mouth
- glossitis,
- erythema multiforme
- lichenoid reactions
- May cause loss of taste
- Angioedema
- Captopril may cause bone marrow depression that can result in anaemia, leukopaenia and thrombocytopaenia.
Give examples of drug interactions ACE inhibitor have relevant to dental practice
ACE inhibitors can be antagonised by ibuprofen. In addition, this combination may lead to hyperkalaemia and renal impairment.
The absorption of tetracyclines is reduced by quinapril.
Give examples of receptor a Angiotensin II receptor antagonists
candesartan, irbesartan and losartan.
Describe the mechanism of action for Angiotensin II receptor antagonists
block type 1 Angiotensin II receptors
this results in vasodilation and a fall in blood pressure
list soem dental side effects of Angiotensin II receptor antagonists
Some reports of taste disturbances
What interactions can Angiotensin II receptor antagonists have in the dental setting
NSAIDS including aspirin reduce the hypotensive effects of Angiotensin II receptor antagonists
corticosteroids also reduce the hypotensive effects
anxiolytic drugs enhance hypotension
What can calcium channel blockers be divided into
- Dihydropyridines, e.g. nifedipine, amlodipine, nicar- dipine and felodopine
- Non-dihydropyridines, e.g. verapamil and diltiazem.
What can calcium channel blockers be divided into
- Dihydropyridines,
- Non-dihydropyridines,
Give examples of Dihydropyridines
nifedipine, amlodipine, nicar- dipine and felodopine
give examples of non Dihydropyridines
verapamil and diltiazem.
Describe the mechanism of action of calcium channel blockers
They bind to L type calcium channels in Smooth muscle
they interfere with the entry of calcium into cells reducing contractility
they exert the effect on blood pressure by arterial vasodilation and a negative inotropic action
Describe the mechanism of action of calcium channel blockers
dilate coronary and peripheral vessels
What dental side effects can calcium channel blockers have on the oral mucosa
Gingival hyperplasia
taste disturbances
What can calcium channel blockers interact with in a dental setting
- Can increase toxicity of lidocaine (not usually a problem)
- may exacerbate the hypokalae- mia induced by adrenaline in dental local anaesthetic cartridges.
- Diltiazem and verapamil increase the effects of midazolam,
Give examples of β-Adrenoreceptor antagonistsused to treat hypertension
atenolol, labetolol, metoprolol and pro- pranolol
Describe the mechanism of action of β-Adrenoreceptor antagonists
- Reduce renin release; β-adrenoreceptor agonists stimulate renin release
- Reduce cardiac output; β-adrenoreceptor action increases the rate and force of contraction of the heart
- Reduce sympathetic activity.
What side effects canβ-Adrenoreceptor antagonists have in the mouth
Dry mouth
Intra oral luchenoid reactions
perioral numbness
How can β-Adrenoreceptor antagonists interact with drugs in the dental setting
- May increase toxicity of LA (not a major concern)
- Ibuprofen antagonises the antihypertensive action of β-adrenoreceptor blockers
Give examples of a-Adrenoreceptor blockers
Doxazosin and prazosin
Describe the mechanism of action of a-Adrenoreceptor blockers
Selective a- agonist produce vasodilation
What side effect can a-Adrenoreceptor blockers have
Postural hypotension seen
