Polymyxin B Dosing Calculator
Vial size, bacteriostatic water, and dose — converted to insulin-syringe units, pre-loaded with Polymyxin B's documented doses.
Typical dose: 1.25 mg/kg – 2.5 mg/kg · intravenous
Polymyxin B documented dose levels
| Phase | Dose | Frequency | Route |
|---|---|---|---|
| Day 1 | Loading dose 2.0-2.5 mg/kg (20,000-25,000 units/kg) | Once on day 1 | Intravenous |
| Days 7-14 | 1.25-1.5 mg/kg (12,500-15,000 units/kg) per dose | Every 12 hours | Intravenous |
| Infection-dependent | 25,000-30,000 units/kg/day divided every 4-6 hours | Every 4-6 hours | Intramuscular |
| At least 2 weeks after CSF cultures turn negative | 50,000 units once daily for 3-4 days, then 50,000 units every other day | Daily then every other day | Intrathecal |
| Until infection resolves | 10,000-25,000 units/mL solution, 1-3 drops | Hourly at first, lengthening the interval as the response allows | Topical |
Reconstitution quick reference
A 5 mg vial at a 1,375 mcg dose of Polymyxin B, by how much bacteriostatic water you add:
| Bacteriostatic water | Concentration | U-100 syringe units per dose |
|---|---|---|
| 1 mL | 5 mg/mL | 28 units |
| 2 mL | 2.5 mg/mL | 55 units |
| 3 mL | 1.667 mg/mL | 83 units |
Different vial size or dose? The calculator above handles any combination.
Polymyxin B dosing questions
What is a typical Polymyxin B dose?
1.25 mg/kg – 2.5 mg/kg · intravenous
How many insulin-syringe units is a Polymyxin B dose?
With a 5 mg vial reconstituted with 2 mL of bacteriostatic water, a 1,375 mcg dose measures 55 units on a U-100 insulin syringe. The calculator above recomputes this for your own vial size, water volume, and dose.
How often is Polymyxin B taken?
Once on day 1
Educational information only — not medical advice. Always consult a qualified healthcare provider.