Can furosemide (Lasix) be administered subcutaneously (SC)?

Subcutaneous Administration of Furosemide

Yes, furosemide can be administered subcutaneously (SC) when oral or intravenous routes are not feasible or desirable. Recent evidence supports this alternative route of administration with demonstrated efficacy and safety considerations.

Efficacy of Subcutaneous Furosemide

• Subcutaneous furosemide has been shown to be an effective diuretic alternative with bioavailability comparable to intravenous administration:
  • A randomized pilot study in healthy volunteers demonstrated statistically significant diuretic and natriuretic effects of SC furosemide 20 mg compared to placebo 1
  • Recent systematic review evidence shows that novel pH-neutral SC furosemide preparations have similar bioavailability (99.7-112%) to intravenous furosemide 2
  • Phase I studies demonstrated that SC furosemide delivered via a patch infusor device had 112% bioavailability compared to IV furosemide, resulting in equivalent diuresis and natriuresis 3

Administration Considerations

Formulation Options

• Novel pH-neutral preparations: Specifically developed for SC administration with fewer local adverse effects

  • High-concentration, pH-neutral formulations (e.g., 80 mg in ~2.7 mL) have been developed for SC administration 3
  • These are better tolerated with minimal skin irritation compared to conventional formulations

• Conventional furosemide: Can be administered SC but with higher risk of local adverse effects

  • Standard preparations are more likely to cause skin irritation (3-23% of patients) and skin infections requiring antibiotics (3-17%) 2

Administration Methods

• Elastomeric pump: Can deliver SC furosemide over extended periods (e.g., 72 hours) for outpatient management of heart failure 4
• Patch infusor device: Small abdominal patch pumps can deliver SC furosemide over 5 hours with minimal discomfort 3
• Direct SC injection: Simple bolus administration is possible but may cause more local irritation

Clinical Applications

• Heart failure management: Particularly useful in:

  • Facilitating early hospital discharge
  • Preventing hospitalizations
  • Palliative care settings
  • Patients with difficult IV access
  • Home-based care where IV administration is not feasible

• Dosing considerations:

  • Initial dosing should be similar to oral or IV doses
  • For heart failure patients, doses of 80-100 mg/day have been studied 3, 4
  • For children with congenital nephrotic syndrome, 0.5-2 mg/kg per dose can be used 5

Safety Considerations and Monitoring

• Local adverse effects:

  • Transient burning and stinging at injection site (most common) 1
  • Risk of skin irritation and infection with conventional formulations 2
  • Novel pH-neutral formulations cause minimal discomfort with 95% of patients reporting no/minor discomfort 3

• Monitoring recommendations:

  • Monitor response within 6-8 hours of administration
  • Check electrolytes and renal function within 3-5 days of initiation 6
  • Watch for electrolyte disturbances, particularly hypokalemia, hyponatremia, and hyperuricemia 6
  • Monitor for orthostatic hypotension by checking blood pressure in both sitting and standing positions 6

Contraindications and Precautions

• Avoid in patients with:

  • Hypotension or hypovolemia 6
  • Anuria 5
  • Known hypersensitivity to furosemide or sulfonamides

• Use with caution in:

  • Elderly patients (consider lower doses)
  • Patients with renal insufficiency (may require dose adjustment)
  • Patients at risk for electrolyte imbalances

Conclusion

Subcutaneous furosemide administration is a viable alternative when oral or IV routes are not feasible. Novel pH-neutral formulations offer better tolerability and equivalent efficacy to IV administration. This route provides an important option for outpatient management of fluid overload, particularly in heart failure patients, and can be considered when traditional administration routes are problematic.