Volume Calculation for 0.02% Ipratropium Bromide Solution
You need 1.25 mL of the 0.02% ipratropium bromide solution to deliver 250 micrograms.
Calculation Breakdown
The math is straightforward:
- 0.02% solution = 0.2 mg/mL (since 0.02% means 0.02 grams per 100 mL = 20 mg per 100 mL = 0.2 mg per mL) 1
- Target dose = 250 micrograms = 0.25 mg 2
- Volume needed = 0.25 mg ÷ 0.2 mg/mL = 1.25 mL 1
Clinical Context for This Dose
For a 13-year-old with post-viral cough, 250 micrograms is the guideline-recommended dose for children in acute exacerbations or when adding ipratropium to beta-agonist therapy 2. The British Thoracic Society specifically states that for children with severe respiratory symptoms who don't improve after initial beta-agonist treatment, you should "repeat at 30 minutes after adding ipratropium bromide 250 µg" 2.
Administration Details
- Nebulize the 1.25 mL dose every 20 minutes for up to 3 doses initially if treating acute severe symptoms 2
- For ongoing post-infectious cough management, use 250 micrograms 3-4 times daily 2
- Can be mixed with albuterol in the same nebulizer if used within one hour 1
- Flow rate should be 6-8 L/min for nebulization 2
Important Safety Note
The 0.02% concentration you have is more dilute than the standard 0.025% (0.25 mg/mL) unit-dose vials typically used, which contain 500 micrograms in 2.5 mL 1. Your calculation must account for this difference—hence why you need 1.25 mL rather than the typical 1 mL volume 1.