How do I dilute a 10mg/ml solution of phenylephrine to 200 mcg/ml?

How to Dilute Phenylephrine 10mg/ml to 200mcg/ml

To dilute a 10mg/ml solution of phenylephrine to 200mcg/ml, withdraw 1ml of the phenylephrine 10mg/ml solution and add it to 49ml of either 0.9% Sodium Chloride or 5% Dextrose solution to create a final volume of 50ml.

Dilution Calculation Explained

The dilution process involves a simple calculation:

1. Starting concentration: 10mg/ml = 10,000mcg/ml
2. Target concentration: 200mcg/ml
3. Dilution factor needed: 10,000mcg/ml ÷ 200mcg/ml = 50-fold dilution

Therefore:

• Take 1ml of phenylephrine 10mg/ml
• Add to 49ml of diluent (0.9% Sodium Chloride or 5% Dextrose)
• Final volume = 50ml of 200mcg/ml solution

Proper Dilution Technique

When preparing this dilution:

• Use proper aseptic technique
• Select the appropriate diluent (0.9% Sodium Chloride or 5% Dextrose) as specified in the FDA label 1
• Use a properly sized syringe for accurate measurement
• Mix thoroughly to ensure uniform concentration
• Label the final solution clearly with:
  • Drug name (phenylephrine)
  • Concentration (200mcg/ml)
  • Date and time of preparation
  • Expiration time

Important Considerations

• The FDA label specifically recommends diluting phenylephrine with either 0.9% Sodium Chloride or 5% Dextrose 1
• Avoid using small volume (1ml) syringes for mixing or dilution as they can lead to inaccurate concentrations 2
• Inspect the solution for particulate matter and discoloration before administration 1
• The diluted solution should not be held for more than 4 hours at room temperature or 24 hours under refrigeration 1
• Discard any unused portion after this time period

Safety Precautions

• Double-check your calculations to avoid dosing errors
• Label the diluted solution immediately to prevent medication errors
• Studies have shown that ad-hoc dilutions can be highly variable and inaccurate 2, so follow the exact measurements
• Be aware that phenylephrine can cause severe cardiovascular effects if administered incorrectly 3, 4
• Consider using standardized protocols for dilution to minimize errors 3

This dilution method will provide a stable phenylephrine solution at the requested concentration of 200mcg/ml, which can be used according to appropriate clinical guidelines.