Special Warning : אזהרת שימוש

4.4 Special warnings and precautions for use

Conditions requiring correction before furosemide is started (see also section 4.3) 

Hypotension.
Hypovolaemia.

Severe electrolyte disturbances – particularly hypokalemia, hyponatremia and acid-base disturbances.


Furosemide is not recommended 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.

Particular caution and/or dose reduction required:

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.


Elderly people (lower initial dose as particularly susceptible to side-effects - see section 4.2) 
Difficulty with micturition including prostatic hypertrophy (increased risk of urinary retention: consider lower dose).
Closely monitor patients with partial occlusion of the urinary tract.

Diabetes mellitus (latent diabetes may become overt: insulin requirements in established diabetes may increase. stop furosemide before a glucose tolerance test).

Pregnancy (see section 4.6).

Gout (furosemide may raise uric acid levels/precipitate gout).
Patients with hepatorenal syndrome.

Impaired hepatic function (see section 4.3 and below – monitoring required).

Impaired renal function (see section 4.3 and below – monitoring required).
Adrenal disease (see section 4.3 – contraindication in Addison's disease).

Hypoproteinemia e.g. nephritic syndrome (effect of furosemide may be impaired and its ototoxicity potentiated - cautious dose titration required).

Acute hypercalcemia (dehydration results from vomiting and diuresis - correct before giving furosemide). Treatment of hypercalcemia with a high dose of furosemide results in fluid and electrolyte depletion - meticulous fluid replacement and correction of electrolyte required.

Patients who are at risk from a pronounced fall in blood pressure

Premature infants (possible development nephrocalcinosis/nephrolithiasis; renal function must be monitored, and renal ultrasonography performed).

Avoidance with other medicines (see also section 4.5 for other interactions) 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 bereduced/stopped (3 days) before starting or increasing the dose of these.


Laboratory monitoring requirements:
Serum sodium
Particularly in the elderly people or in patients liable to electrolyte deficiency Serum potassium


The possibility of hypokalemia 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.
Regular monitoring of the potassium, and if necessary, treatment with a potassium supplement, is recommended in all cases, but is essential at higher doses and in patients with impaired renal function. It is especially important in the event of concomitant treatment with digoxin, as potassium deficiency can trigger or exacerbate the symptoms of digitalis intoxication (see section 4.5). A potassium-rich diet is recommended during long-term use.
Frequent checks of the serum potassium are necessary in patients with impaired renal function and creatinine clearance below 60ml/min per 1.73m2 body surface area as well as in cases where furosemide is taken in combination with certain other drugs which may lead to an increase in potassium levels (see section 4.5 & refer to section 4.8 for details of electrolyte and metabolic abnormalities).
Renal function
Frequent BUN in first few months of treatment, periodically thereafter. Long-term/high-dose BUN should regularly be measured. Marked diuresis can cause reversible impairment of kidney function in patients with renal dysfunction.
Adequate fluid intake is necessary in such patients. Serum creatinine and urea levels tend to rise during treatment.
Glucose
Adverse effect on carbohydrate metabolism - exacerbation of existing carbohydrate intolerance or diabetes mellitus.
Regular monitoring of blood glucose levels is desirable.
Other electrolytes
Patients with hepatic failure/alcoholic cirrhosis are particularly at risk of hypomagnesemia (as well as hypokalemia).
During long-term therapy (especially at high doses) magnesium, calcium, chloride, bicarbonate, and uric acid should be regularly measured.
Clinical monitoring requirements (see also section 4.8):
Regular monitoring for blood dyscrasias. If these occur, stop furosemide immediately.
liver damage idiosyncratic reactions.
Other alterations in lab values
Serum cholesterol and triglycerides may rise but usually return to normal within 6 months of starting furosemide.
Concomitant use with risperidone
In risperidone placebo-controlled trials in elderly people with dementia, a higher incidence of mortality was observed in patients treated with furosemide plus risperidone (7.3%; mean age 89 years, range 75-97 years) when compared to patients treated with risperidone alone (3.1%; mean age 84 years, range 70-96 years) or furosemide alone (4.1%; mean age 80 years, range 67-90 years). Concomitant use of risperidone with other diuretics (mainly thiazide diuretics used in low dose) was not associated with similar findings.
No pathophysiological mechanism has been identified to explain this finding, and no consistent pattern for cause of death observed. Nevertheless, caution should be exercised and the risks and benefits of this combination or co-treatment with other potent diuretics should be considered prior to the decision to use. There was no increased incidence of mortality among patients taking other diuretics as concomitant treatment with risperidone. Irrespective of treatment, dehydration was an overall risk factor for mortality and should therefore be avoided in elderly patients with dementia (see section 4.3 Contraindications).
Furovenir 250mg/25ml Solution for Infusion contains 92 mg sodium per 25ml ampoule, equivalent to 4.5% of the WHO recommended maximum daily intake of 2 g sodium for an adult.


Effects on Driving

4.7 Effects on ability to drive and use machines


Reduced mental alertness, dizziness and blurred vision have been reported, particularly at the start of treatment, with dose changes and in combination with alcohol. Patients should be advised that if affected, they should not drive, operate machinery or take part in activities where these effects could put themselves or others at risk.