When is Lasix (furosemide) injectable administered?

When to Administer Lasix (Furosemide) Injectable

Administer IV furosemide in acute heart failure with pulmonary edema or when patients cannot take oral medication, always in combination with nitrate therapy for moderate-to-severe cases, not as monotherapy. 1

Primary Indications for Injectable Furosemide

Emergency situations requiring rapid diuresis:

• Acute pulmonary edema requiring immediate onset of diuresis 2
• Acute decompensated heart failure with severe dyspnea and fluid overload 3, 2
• Patients unable to take oral medication due to gastrointestinal absorption impairment or clinical instability 2

Edematous states requiring parenteral therapy:

• Congestive heart failure with significant fluid retention 2
• Cirrhosis of the liver with edema 2
• Renal disease including nephrotic syndrome 2

Critical Treatment Algorithm

For moderate-to-severe pulmonary edema (Level B recommendation):

• Always combine furosemide with nitrate therapy—never use aggressive diuretic monotherapy 1
• Aggressive diuretic monotherapy is unlikely to prevent intubation compared to aggressive nitrate therapy 1
• High-dose nitrates combined with low-dose furosemide showed better outcomes (reduced death, MI, and intubation) than high-dose furosemide with low-dose nitrates 1

Initial dosing strategy:

• Diuretic-naïve patients or new-onset acute heart failure: Start with 20-40 mg IV furosemide 4, 5, 2
• Patients on chronic oral diuretics: Give at least the equivalent of their oral dose IV 4, 5, 2
• Acute pulmonary edema: Initial dose is 40 mg IV given slowly over 1-2 minutes; may increase to 80 mg if no response within 1 hour 2

Administration Method

Route and rate:

• Administer slowly IV over 1-2 minutes to avoid ototoxicity 2
• Can be given as intermittent boluses every 12 hours or continuous infusion 4, 3
• For high-dose therapy, use controlled IV infusion at rate not exceeding 4 mg/min 2

Dose escalation:

• If inadequate response, increase by 20 mg increments no sooner than 2 hours after previous dose 2
• Maximum dose for premature infants should not exceed 1 mg/kg/day 2

Essential Monitoring Requirements

During IV diuretic therapy, monitor:

• Symptoms and urine output continuously 4, 5
• Renal function and electrolytes regularly 4, 3, 5
• Blood pressure for hypotension risk 1
• Consider bladder catheterization for accurate output monitoring 5

Critical Pitfalls and Contraindications

Situations where furosemide is unlikely to work or may cause harm:

• Hypotension (SBP <90 mmHg) predicts poor diuretic response 5
• Severe hyponatremia or acidosis reduces effectiveness 5
• Furosemide transiently worsens hemodynamics for 1-2 hours (increased systemic vascular resistance, increased left ventricular filling pressures, decreased stroke volume) 1

Renal function concerns (Level C recommendation):

• Administer diuretics judiciously due to potential association with worsening renal function 1
• Worsening renal function at index hospitalization is associated with increased long-term mortality 1
• High doses may cause hypovolemia and hyponatremia, increasing hypotension risk when starting ACE inhibitors 3, 5

When to Transition from IV to Oral

Replace parenteral therapy with oral furosemide as soon as practical once:

• Patient can tolerate oral medication 2
• Emergency situation has resolved 2
• Adequate diuresis has been achieved and patient is clinically stable 2

Special Populations

Pediatric dosing:

• Initial dose: 1 mg/kg IV or IM given slowly under close supervision 2
• May increase by 1 mg/kg increments (not sooner than 2 hours) if inadequate response 2
• Maximum 6 mg/kg body weight (not to exceed 1 mg/kg/day in premature infants) 2

Geriatric patients:

• Start at low end of dosing range with cautious dose selection 2