CHAPTER 2: CVS: Oedema Flashcards
What are the two types of diuretics used? (2)
- Thiazides
2. Loop
Can both loop and thiazide diuretics be used?
Yes, in patients with oedema resistant to just one diuretic
What can vigorous diuresis induce?
Hypotension
How long after administration do thiazide diuretics act?
Within 1-2 hours
What is the duration of action of thiazide diuretics?
12-24 hours
Low dose thiazide diuretics produce good BP lowering effects, what can higher dose lead to changes in? (electrolytes)
- Potassium (hypokalaemia)
- Sodium (hyponatreamia)
- Uric acid
- Glucose
- Lipids
What are the thiazide diuretics of choice? (2)
- Chlortalidone
2. Indapamide
Which thiazide diuretic licensed for use in mild to moderate heart failure is no longer first line?
Bendroflumethiazide
Which thiazide diuretic can be given on alternate days due to its long duration of action?
Chlortalidone
In which condition is chlortalidone really useful in?
Ascites due to cirrhosis in stable patients
Which thiazide diuretic lowers BP with less metabolic effects?
Indapamide
What is the man indication for loop diuretics?
Pulmonary oedema due to left ventricular failure
Which 2 conditions can diuretics exacerbate?
- Diabetes
2. Gout
If a patient with an enlarged prostate is being treated with diuretics, what may occur?
Urinary retention - reduce dose and potency
How long does it take for loop diuretics to start working?
1 hour
What is the duration of action of loop diuretics?
6 hours
Can loop diuretics be given twice daily?
Yes, as long as they don’t interfer with sleep
Give an example of a potassium sparing diuretic
Amiloride
Why are potassium sparing diuretics and aldosterone antagonists given with loop diuretics?
To retain potassium - more effective alternative to potassium supplements
Give an example of an aldosterone antagonist
Spironolactone
Can potassium supplements be given with potassium-sparing diuretics or aldosterone antagonists?
No
What should be corrected before treatment with diuretics? (2)
- Hypotension
2. Hypovoleamia
In which population should lower initial doses of diuretics be used? They are more susceptible to side effects
Elderly
Are diuretics indicated for simple gravitational oedema?
No
What should be advised to manage simple gravitational oedema? (3)
- Increased movement
- Raising legs
- Stockings
What are the notable drug interactions with diuretics? (5)
- Digoxin - toxicity due to hypokalaemia
- Lithium - toxicity due to impaired renal function and hyponatreamia (body can’t tell the difference so will retain it)
- Potassium sparring diuretics
- ACE inhibitors
- NSAIDs
