From the Guidelines
To determine the rate of a Lasix (furosemide) drip, you should first calculate the concentration of the solution and then use the prescribed dose in mg/hr to find the infusion rate in mL/hr, with the initial recommended dose being 20–40 mg i.v. furosemide (or equivalent) for patients with new-onset AHF or those with chronic, decompensated HF not receiving oral diuretics 1. When calculating the rate, consider the following steps:
- Calculate the concentration by dividing the total amount of Lasix (in mg) by the total volume of solution (in mL)
- Determine the infusion rate in mL/hr by dividing the prescribed dose rate (mg/hr) by the concentration (mg/mL) For example, if you have 100 mg of Lasix in 100 mL of solution (concentration = 1 mg/mL) and the order is for 10 mg/hr, the infusion rate would be 10 mL/hr. It is essential to monitor the patient closely for fluid status, electrolytes (especially potassium), and urine output, as Lasix is a potent loop diuretic that can cause significant fluid and electrolyte shifts 1. Some key points to consider when administering Lasix include:
- The initial recommended dose should be 20–40 mg i.v. furosemide (or equivalent) for patients with new-onset AHF or those with chronic, decompensated HF not receiving oral diuretics 1
- Diuretics should be given either as intermittent boluses or as a continuous infusion, and the dose and duration should be adjusted according to patients’ symptoms and clinical status 1
- Combination of loop diuretic with either thiazide-type diuretic or spironolactone may be considered in patients with certain conditions 1 Always verify your institution's protocol for Lasix drip preparation and administration, and adjust the rate as needed based on the patient's response and physician orders.
From the FDA Drug Label
If the physician elects to use high dose parenteral therapy, add the furosemide to either Sodium Chloride Injection USP, Lactated Ringer's Injection USP, or Dextrose (5%) Injection USP after pH has been adjusted to above 5. 5, and administer as a controlled intravenous infusion at a rate not greater than 4 mg/min. If the physician elects to use high dose parenteral therapy, controlled intravenous infusion is advisable (for adults, an infusion rate not exceeding 4 mg furosemide per minute has been used)
The rate for Lasix gtt (furosemide IV) can be determined as not greater than 4 mg/min for high dose parenteral therapy in adults, as a controlled intravenous infusion 2 2.
From the Research
Determining the Rate of Lasix Gtt
To determine the rate of Lasix gtt (furosemide), several factors need to be considered, including the patient's renal function, intravascular volume status, and the severity of acute kidney injury (AKI) 3.
- The severity of AKI, as reflected by the measured creatinine clearance, alters both pharmacokinetics and pharmacodynamics of furosemide in AKI, and was the only reliable predictor of the urinary output response to furosemide in AKI 3.
- A continuous infusion of furosemide may be superior to bolus doses in achieving a diuretic response, especially in patients with severe AKI or those requiring continuous venovenous hemofiltration dialysis (CVVHDF) 4, 5.
- The dose of furosemide can be adjusted according to hourly urine output, with higher doses potentially leading to increased urine output and improved kidney function 5.
- The response to furosemide can be highly variable and is influenced by factors such as age, mean arterial pressure, and creatinine and albumin levels 6.
Considerations for Administration
When administering furosemide, the following considerations should be taken into account:
- The pharmacokinetics and pharmacodynamics of furosemide can be altered in patients with AKI, leading to reduced diuretic response 3.
- Continuous infusion of furosemide may allow for more reliable assessment of glomerular and tubular functions compared to bolus doses 4.
- High-dose furosemide infusion can increase urine output and improve success rates in patients with early AKI complicated by acute pulmonary edema 5.