Furosemide Intramuscular Administration Guidelines
The recommended intramuscular (IM) dose of furosemide is 20-40 mg as a single dose, which should be replaced with oral therapy as soon as practical. 1
Dosing Recommendations
Adults:
- Initial dose: 20-40 mg IM as a single dose
- Additional doses may be administered after 2 hours if needed
- Dose may be increased by 20 mg increments (not sooner than 2 hours after previous dose)
- Therapy should be individualized according to patient response
Special Populations:
- Geriatric patients: Start at the lower end of dosing range (20 mg)
- Pediatric patients: 1 mg/kg body weight IM
- May increase by 1 mg/kg not sooner than 2 hours after previous dose
- Maximum recommended dose: 6 mg/kg body weight
- For premature infants: Maximum 1 mg/kg/day
Clinical Applications
Furosemide IM is indicated in patients who:
- Are unable to take oral medication
- Require emergency treatment
- Have edematous conditions associated with:
- Heart failure
- Renal failure
- Hepatic failure
- Hypertension
Monitoring Parameters
When administering IM furosemide, monitor:
- Urine output
- Blood pressure (avoid in hypotensive patients with SBP <90 mmHg)
- Electrolytes (particularly potassium, sodium)
- Renal function
Precautions and Contraindications
- Hypotension: Avoid increasing diuretic doses in patients with systolic blood pressure <90 mmHg 2
- Acid-base balance: Furosemide is a buffered alkaline solution with pH of about 9
- Renal insufficiency: Adjust dosing frequency in patients with renal dysfunction
- Pregnancy: Use with caution
Potential Adverse Effects
- Fluid and electrolyte disturbances (hypokalemia, hyponatremia, hyperuricemia)
- Hypovolemia and dehydration
- Neurohormonal activation
- Ototoxicity (particularly with high doses)
- Potential for hypotension following initiation of ACE inhibitors/ARBs 3
Practical Considerations
- IM furosemide should be replaced with oral therapy as soon as practical 1
- Inspect solution visually for particulate matter and discoloration before administration
- Do not use if solution is discolored
- IM administration is an alternative when IV access is not available or in emergency situations
- The bioavailability of furosemide is highly variable, which may affect clinical response 4
Clinical Pearls
- In acute heart failure, IV administration is generally preferred over IM when possible 3
- For acute pulmonary edema, IV administration is typically recommended at 40 mg initially 3
- IM furosemide has been shown to induce prompt diuresis and solute loss similar to other routes of administration 5
- Consider combination therapy with other diuretics (thiazides, aldosterone antagonists) in cases of diuretic resistance 3
Remember that parenteral therapy with furosemide should be used only when oral medication cannot be taken or in emergency situations, and should be replaced with oral therapy as soon as practical.