Floxacillin sodium is available in vials containing 250 mg, 500 mg, and 1 g of floxacillin as the sodium salt. To reconstitute for intramuscular use, add 1.5 mL of sterile water for injection to the 250-mg vial, 2 mL to the 500-mg vial, or 2.5 mL to the 1-g vial.38; 115
For intravenous use, reconstitute the 250- or 500-mg vial with 5 to 10 mL and the 1-g vial with 15 to 20 mL of sterile water for injection. For intravenous infusion, the solution may be diluted further in a compatible infusion fluid.38; 115
For intrapleural use, reconstitute the 250-mg vial with 5 to 10 mL of sterile water for injection. For intra-articular use, reconstitute the 250- or 500-mg vial with up to 5 mL of sterile water for injection or lidocaine hydrochloride 0.5% injection.38; 115
For smaller doses, the reconstitution volumes in Table 1 will yield the indicated concentrations.
Table 1. Floxacillin Reconstitution Volumes for Smaller Doses38; 115
| Concentration (mg/1 mL) | ||||||
|---|---|---|---|---|---|---|
| Vial Size | 50 | 100 | 125 | 200 | 250 | 500 |
| 250 mg | 4.8 mL | 2.3 mL | 1.8 mL | 1.05 mL | ||
| 500 mg | 4.7 mL | 3.7 mL | 2.2 mL | 1.7 mL | ||
| 1 g | 9.3 mL | 3.3 mL | 1.3 mL | |||
Sodium and Magnesium Content
Each gram of drug contains 2.2 mmol (51 mg) of sodium and 1 mmol of magnesium.38; 89; 115
Trade Name(s)
Floxapen, Ladropen
Floxacillin sodium may be administered by intramuscular injection, direct intravenous injection slowly over three to four minutes, continuous intravenous infusion, and intrapleural and intra-articular injection.38
Floxacillin sodium in intact vials should be stored below 25°C. The injection reconstituted for intramuscular or direct intravenous injection should be freshly prepared and administered within 30 minutes. However, reconstituted floxacillin sodium injection is stated to be stable for 24 hours when stored under refrigeration.38; 115
Losses of 8% in three days were reported for reconstituted solutions containing floxacillin sodium (Beecham) 100 mg/mL stored at 20 to 25°C.89
Freezing Solutions
Floxacillin sodium (Beecham) 20 mg/mL in sodium chloride 0.9% or dextrose 5% in PVC bags (Travenol) retained greater than 90% after being frozen and stored at -27°C for up to 270 days. Thawing by microwave radiation and subsequent storage for 24 hours at 4°C did not cause drug loss below 90% of the stated concentration. However, a distinct yellow discoloration was produced after 90 days of storage, rendering the solutions unacceptable.1176
Floxacillin sodium (Beecham) 1 g in 50 mL of sodium chloride 0.9% or dextrose 5% in PVC bags (Travenol) was stored at -20°C for 30 days, followed by natural thawing and storage at 5°C for 21 hours. The drug was stable under these conditions for the duration of the study.299
Sorption
Floxacillin sodium was shown not to exhibit sorption to PVC bags and tubing, polyethylene tubing, Silastic tubing, and polypropylene syringes.536; 606
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