How to Prepare 80 mg Lasix from a 100 mg/100 mL Solution
To obtain 80 mg of furosemide from a 100 mg/100 mL solution, withdraw 80 mL of the solution—no reconstitution or dilution is necessary.
Simple Calculation
The concentration you have is 1 mg/mL (100 mg in 100 mL). To deliver 80 mg:
- Volume needed = 80 mL
Administration Guidelines
According to FDA labeling, when administering furosemide intravenously 1:
- Inject slowly over 1-2 minutes for standard doses
- For doses of 80 mg, this slow IV push over 1-2 minutes is the standard approach
- Do not exceed 4 mg/min if using continuous infusion for high-dose therapy
Important Compatibility Considerations
If you need to dilute furosemide for any reason 1, 2:
- Compatible diluents: 0.9% Normal Saline (NS), Lactated Ringer's (LR), or 5% Dextrose (D5W)
- Critical pH requirement: The solution pH must be adjusted to above 5.5 before adding furosemide, as it precipitates in acidic solutions (furosemide has a pH of 8.0-9.3)
- Never mix with acidic medications (labetalol, ciprofloxacin, amrinone, milrinone) as precipitation will occur
- Research demonstrates that dilutions to 10 mg/mL in NS, LR, or D5W remain stable for 8 hours 2
Key Safety Points
- Furosemide is a potent diuretic requiring careful medical supervision 1
- Monitor for profound diuresis and electrolyte depletion
- The slow administration rate (1-2 minutes for IV push) is essential to minimize adverse effects 1
In your case with a pre-mixed 100 mg/100 mL solution, simply draw up 80 mL and administer slowly over 1-2 minutes.