Oedema Flashcards
1
Q
Loop diuretics
Common indications
A
- Releif of breathlessness in acute pulmonary oedema in conjunction with O2 and nitrates
- Symptomatic releif of fluid overload in chronic heart failure
- Symptomatic releif of fluid overload in other oedema diseases e.g. Ascites, CKD
2
Q
Loop diuretics
MOA
A
- They work on the ascending loop of henle, where they inhibit the Na/K/2Cl co-transporter
- This protein is responsible for transporting Na, K and Cl ions from the tubular lumen into the epithelial cell. Water then follows by osmosis
- In addition to loop diuretics have a direct effect on the blood vessels causing dilation of the capacitance veins
- In acute heart failure, this reduces preload and improves contractile function of hte overstretched heart muscle
- Indeed, this is probably the main benefit of loop diuretics in HF
3
Q
Loop diuretics
Important adverse effects
A
- Water losses due to diuresis can led to dehydration and hypotension
- Inhibiting the Na/K/2Cl co-transporter increases urinary losses Na/K/Cl
- Indirectly, this increases excretion of Mg, Ca + H ions
- Associated with most low electrolyte state (including acidosis)
- A similar Na/K/2Cl co-transporter is responsible for regulating endolymph composition in the inner ear
- At high doses, loop diuretics can affect this too, leading to hearing loss and tinitus
4
Q
Loop diuretics
Warnings
A
- Contraindicated: Hypovolaemia, dehydration, AKI
- Caution; Hepatic encephalopathy (hypokalaemia can worsen/cause a coma), Hypokalaemia and/or hyponatraemia
- Loop diuretics inhibit uric acid excretion and this can worsen gout
5
Q
Loop diuretics
Interactions
A
- Loop diuretics have the potential to affect drugs that are excreted by the kidneys
- For example, Li levels are increased due to reduced excretion
- Digoxin toxicity may also be increased, due to the effect of diuretic-associated hypokalaemia
- Loop diuretics can increase the ototoxicity and nephrotoxicity of aminoglycosides
6
Q
Loop diuretics
Communication
A
- Explain that your patient that their body is overloaded with water
- You are therefore offering a treatment to increase urine flow, which will hopefully improve this
- The medicine will inevitably cause them to need to pass water more often
- Provided they do not take doses late in the day it should not affect them at night
7
Q
Loop diuretics
Monitoring
A
- Efficacy in the acute management of pulmonary oedema, evidence for good response will include improvements in the patients symptoms, tachycardia, hypertension and O2 requirements
- Increase UO typically occurs later and indicates onset of the diuretic effect
- In the longer-term therapy, you should monitor your patients symptoms and body weight (1kg/day)
- Safety: Periodic monitoring of serum Na, K and renal function is also advisable, particularly in the first few weeks of therapy