Oedema Flashcards
1
Q
Thiazide Diuretics
A
- Thiazides are used to relieve oedema in chronic heart failure and in lower doses to reduce BP.
- Higher doses produce no additional benefit and cause more changes in potassium, sodium, uric acid, glucose and lipids.
- Thiazides cause low potassium, sodium and magnesium, and high calcium and glucose (they can exacerbate diabetes). Electrolytes should be monitored.
- They act within 1-2 hours and most have a duration of action of 12-24 hours. They are administered early in the day so that diuresis does not interfere with sleep.
- Indapamide is preferred to Bendroflumethiazide in hypertension, whereas Bendroflumethiazide is used in HF.
- Indapamide lowers BP with less metabolic disturbance, particularly less aggravation of diabetes
- Avoid giving with Lithium – sodium depletion increases the risk of toxicity
- Avoid giving with a Beta-blocker for hypertension in those with diabetes, or at risk of developing diabetes.
2
Q
Eye drops in glaucoma
A
- Acetazolamide and eye drops of dorzolamide + brinzolamide inhibit the formation of aqueous humour and are used in glaucoma
3
Q
-Many patients on diuretics don’t need
A
potassium supplements.
4
Q
Loop Diuretics
A
- Loop diuretics are used for pulmonary oedema due to left ventricular failure and patients with chronic heart failure.
- Diuretic-resistant oedema can be treated with a loop diuretic + thiazide/related diuretic.
- They can also be added to antihypertensive treatment to achieve better control of hypertension in those with resistant hypertension or in patients with impaired renal function/heart failure.
- They work within an hour and diuresis occurs within 6 hours – so if necessary they can be given twice in one day without interfering with sleep.
- Rapid I.V. administration causes tinnitus or deafness. They should not be given with aminoglycosides (e.g. gentamicin or vancomycin) due to the risk of ototoxicity (ear toxicity)
- Loop diuretics may cause hyperglycaemia but are less likely to exacerbate diabetes than thiazide’s
- They also reduce excretion of lithium but are better than thiazides.
5
Q
Potassium-sparing diuretics and aldosterone antagonists
A
- Potassium-sparing diuretics are given with thiazide or loop diuretics for the retention of potassium instead of potassium supplements. An example is Amiloride.
- Potassium supplements should not be given with potassium-sparing diuretics. They should not be given with ACEI or ARBs due to the risk of hyperkalaemia.
- Spironolactone potentiates thiazide/loop diuretics may antagonising aldosterone. It is a potassium sparing diuretic. It can be used in the treatment of oedema and ascites caused by liver cirrhosis, furosemide can be used as an adjunct.
- Low doses of spironolactone are of benefit in moderate-severe HF and when used in resistant hypertension.
- Eplerenone is used as an adjunct in left ventricular dysfunction with evidence of HF after an MI. It can also be used as an adjunct in chronic mild HF.
- Potassium supplements must not be given with aldosterone antagonists.
6
Q
Which diuretics cause hypokalaemia
A
All diuretics cause hypokalaemia except potassium sparing diuretics and aldosterone antagonists as they INCREASE K+ Levels
7
Q
HTN + HF give
A
indapamide
8
Q
Loop diuretics examples
A
- Bumetanide
- Furosemide
- Torsemide
9
Q
Thiazides examples
A
- Bendroflumethiazide
- Cyclopenthiazide
- Chlorothiazide
10
Q
Thiazide related examples
A
- Clortalidone (long half life)
- Indapamide
- Metolazone (use in renal patients)
- Xipamide
11
Q
Carbonic anhydrase inhibitors examples
A
Acetazolamide (use in glaucoma)
12
Q
Potassium sparing diuretics examples
A
- Amiloride
- Triamterene (blue tinge to urine in some lights)
13
Q
Aldosterone antagonists examples
A
- Spironolactone
- Eplerenone
14
Q
Osmotic diuretics examples
A
- Mannitol (brain swelling)
