DocTayo Pharmacy Calculation Tool

Inhaler Days' Supply Calculator

Calculate scheduled days' supply or a clearly labeled maximum-use PRN estimate from the exact package count and directions.

Verify the exact device and NDC. Product families may have 14, 28, 30, 60, 120, or 200 labeled units. The calculator performs arithmetic and does not determine whether the regimen is clinically appropriate.

Enter the prescription

Do not automatically subtract priming sprays. Use this only when the product-specific information and approved billing procedure require an adjustment.

Calculation result

Days' supply - Enter the prescription and calculate.
Formula: total usable units ÷ daily use

Interpretation

The result will state whether it is a scheduled calculation or a maximum-use PRN estimate.

Calculation cautions

  • For PRN directions, actual use cannot be predicted. The shortest permitted interval produces a maximum-use estimate.
  • Directions based only on exercise, symptoms, or an unstated frequency may require clarification.
  • A fractional quotient may be handled differently by different claim systems. This tool displays the exact quotient and the calendar depletion day.
  • Verify package count, device type, dose counter, opening discard period, and current labeling.
  • Do not use extra maintenance-inhaler doses unless the regimen specifically supports them.