What are the therapeutic indications for furosemide?
o The treatment of fluid retention associated with heart failure, including left ventricular failure, cirrhosis of the liver and renal disease, including the nephrotic syndrome.
o The treatment of mild to moderate hypertension when brisk diuretic response is required. Alone or in combination with other antihypertensive agents in the treatment of more severe cases.
What are the contraindications for furosemide?
- Hypersensitivity to furosemide
- Hypovolaemia and dehydration
- Severe hypokalaemia, severe hyponatraemia
- Comatose or pre-comatose states associated with hepatic cirrhosis
- Anuria or renal failure with anuria not responding to furosemide, renal failure as a result of poisoning by nephrotoxic or hepatotoxic agents or renal failure associated with hepatic coma.
- Impaired renal function
- Addison’s disease
- Children under 18 years of age
- Digitalis intoxication
- Concomitant potassium supplements or potassium sparing diuretics
- Porphyria
- Breast-feeding women
Which conditions require correction before furosemide is started?
o Hypotension.
o Hypovolaemia.
o Severe electrolyte disturbances – particularly hypokalaemia, hyponatraemia and acid-base disturbances.
When is furosemide not recommended?
o In patients at high risk for radiocontrast nephropathy - it should not be used for diuresis as part of the preventative measures against radiocontrast-induced nephropathy.
o In patients with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption.
When should particular caution and/or dose reduction required when prescribing furosemide?
o elderly patients (lower initial dose as particularly susceptible to side-effects)
o difficulty with micturition including prostatic hypertrophy (increased risk of urinary retention: consider lower dose). Closely monitor patients with partial occlusion of the urinary tract.
o diabetes mellitus (latent diabetes may become overt: insulin requirements in established diabetes may increase: stop furosemide before a glucose tolerance test)
o pregnancy
o gout (furosemide may raise uric acid levels/precipitate gout)
o patients with hepatorenal syndrome
o impaired hepatic function
o impaired renal function
o adrenal disease
o hypoproteinaemia e.g. nephrotic syndrome (effect of furosemide may be impaired, and its ototoxicity potentiated - cautious dose titration required).
o acute hypercalcaemia (dehydration results from vomiting and diuresis - correct before giving furosemide). Treatment of hypercalcaemia with a high dose of furosemide results in fluid and electrolyte depletion - meticulous fluid replacement and correction of electrolyte required.
o Patients who are at risk from a pronounced fall in blood pressure
o premature infants (possible development nephrocalcinosis/nephrolithiasis; renal function must be monitored and renal ultrasonography performed).
o Symptomatic hypotension leading to dizziness, fainting or loss of consciousness can occur in patients treated with furosemide, particularly in the elderly, patients on other medications which can cause hypotension and patients with other medical conditions that are risks for hypotension
Which medications should you avoid prescribing a patient when they are taking furosemide?
- Concurrent NSAIDs should be avoided – if not possible diuretic effect of furosemide may be attenuated
- ACE-inhibitors & Angiotensin II receptor antagonists – severe hypotension may occur – dose of furosemide should be reduced/stopped (3 days) before starting or increasing the dose of these
Which laboratory monitoring are required for furosemide?
Serum sodium- particularly in the elderly or in patients liable to electrolyte deficiency
Serum potassium- the possibility of hypokalaemia should be taken into account, in particular in patients with cirrhosis of the liver, those receiving concomitant treatment with corticosteroids, those with an unbalanced diet and those who abuse laxatives.
Renal function
Regular monitoring for blood dyscrasias, liver damage and idiosyncratic reactions.
Concomitant use of risperidone is not recommended.
Common side effects of furosemide
- mild gastro-intestinal disturbances
- postural hypotension
- electrolyte disturbances (including hyponatraemia, hypokalaemia, hypocalcaemia, hypochloraemia, and hypomagnesaemia)
- hypersensitivity reactions (including rash, photosensitivity, and pruritus)
Uncommon side effects of furosemide
- pancreatitis
- hepatic encephalopathy
- temporary increase in serum-cholesterol and triglyceride concentration
- hyperglycaemia (less common than with thiazides)
- acute urinary retention
- metabolic alkalosis
- blood disorders (including bone-marrow depression, thrombocytopenia, and leukopenia)
- hyperuricaemia
- visual disturbances
- tinnitus
- deafness (usually with high parenteral doses and rapid administration, and in renal impairment)
Which organ function should you check with aspirin?
Renal function
Which organ function should you check with gabapentin?
Renal function
Which organ function should you check with furosemide?
Renal function
Which organ function should you check with atorvastatin?
Liver function and cholesterol
Which organ function should you check with ramipril?
Renal function
Which organ function should you check with levothyroxine?
Thyroid function
Why should you monitor renal function with metformin?
There’s an increased risk of lactic acidosis if metformin given with renal impairment. NICE recommend that medication be stopped if sudden deterioration in renal function, and avoid if eGFR less than 30mL/minute/1.732
