DOSAGE AND ADMINISTRATION
Important:
Colistimethate for injection is supplied in vials containing colistimethate sodium equivalent to 150 mg colistin base activity per vial.
Reconstitution:
The 150 mg vial should be reconstituted with 2.0 mL Sterile Water for Injection, USP. The reconstituted solution provides colistimethate sodium at a concentration equivalent to 75 mg/mL colistin base activity.
During reconstitution swirl gently to avoid frothing.
Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. If these conditions are observed, the product should not be used.
Dosage
Adults and pediatric patients – Intravenous or Intramuscular Administration:
Colistimethate for injection should be given in 2 to 4 divided doses at dose levels of 2.5 to 5 mg/kg per day for patients with normal renal function, depending on the severity of the infection.
In obese individuals, dosage should be based on ideal body weight.
The daily dose should be reduced in the presence of renal impairment. Modifications of dosage in the presence of renal impairment are presented in Table 1.
TABLE 1. Suggested Modification of Dosage Schedules of Colistimethate for Injection for Adults with Impaired Renal function | Renal Function | Degree of Impairment |
|---|
| Normal | Mild | Moderate | Considerable |
|---|
| Note: The suggested unit dose is 2.5 to 5 mg/kg; however, the time INTERVAL between injections should be increased in the presence of impaired renal function. |
| Plasma creatinine, mg/100 mL | 0.7–1.2 | 1.3–1.5 | 1.6–2.5 | 2.6–4.0 |
| | | | | |
| Urea clearance, % of normal | 80–100 | 40–70 | 25–40 | 10–25 |
| | | | | |
| Dosage | | | | |
| | | | | |
Unit dose of Colistimethate
for injection, mg | 100–150 | 75–115 | 66–150 | 100–150 |
| | | | | |
| Frequency, times/day | 4 to 2 | 2 | 2 or 1 | every 36 hr |
| | | | | |
| Total daily dose, mg | 300 | 150–230 | 133–150 | 100 |
| | | | | |
| Approximate daily dose, mg/kg/day | 5 | 2.5–3.8 | 2.5 | 1.5 |
INTRAVENOUS ADMINISTRATION
1. Direct Intermittent Administration—Slowly inject one-half of the total daily dose over a period of 3 to 5 minutes every 12 hours.
2. Continuous Infusion—Slowly inject one-half of the total daily dose over 3 to 5 minutes. Add the remaining half of the total daily dose of colistimethate for injection to one of the following:
- 0.9% NaCl
- 5% dextrose in 0.9% NaCl
- 5% dextrose in water
- 5% dextrose in 0.45% NaCl
- 5% dextrose in 0.225% NaCl
- Lactated Ringer's solution
- 10% invert sugar solution
There are not sufficient data to recommend usage of colistimethate for injection with other drugs or other than the above listed infusion solutions.
Administer the second half of the total daily dose by slow intravenous infusion, starting 1 to 2 hours after the initial dose, over the next 22 to 23 hours. In the presence of impaired renal function, reduce the infusion rate depending on the degree of renal impairment.
The choice of intravenous solution and the volume to be employed are dictated by the requirements of fluid and electrolyte management.
Any infusion solution containing colistimethate sodium should be freshly prepared and used for no longer than 24 hours.
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