Loop diuretics

Question 1

Indications

Answer 1

1. For relief of breathlessness in acute pulmonary oedema in conjunction with oxygen and nitrates
2. For symptomatic treatment of fluid overload in chronic heart failure
3. For symptomatic treatment of fluid overload in other oedematous states e.g. renal disease

Question 2

Mechanism of action

Answer 2

Act principally on the loop of Henle where they inhibit the Na+/K+ co-transporter (transports Na and K from tube lumen into epithelial cell = water uptake). Inhibition of this inhibits water uptake and more is excreted by the kidneys.

Question 3

Adverse effects

Answer 3

Dehydration
Hypotension
Low electrolyte state

Question 4

Warnings

Answer 4

Contraindicated in hypovolaemia and dehydration.

Should be used with caution in hepatic encephalopathy, hypokalaemia, hyponatraemia and gout

Question 5

Interactions

Answer 5

Have the potential to effect any drugs undergoing renal excretion e.g. lithium, digoxin

Can increases otoxicity and nephrotoxicty of aminoglycosides.

Question 6

Prescription

Answer 6

PO and IV. In acute management give the first dose IV eg 40mg furosemide IV

Question 7

Administration

Answer 7

IV furosemide should be administered slowly at a rate no greater than 4mg/min

Question 8

Communication

Answer 8

Explain to patient that their body is overloaded with water and this drug will increase urine flow.

Question 9

Monitoring

Answer 9

Periodic monitoring of serum solution and renal function is advised.