How it works & sources
Where the dosing values come from, how the arithmetic runs, and — just as importantly — where this app rounds, estimates, assumes, or has no citation yet.
Dosing references
Every drug in the catalog names its dosing reference, and that reference is shown where the number appears rather than in a footnote. Across 92 drugs:
| Source | Drugs |
|---|---|
| IDAI | 40 |
| BNFc | 34 |
| Fornas | 8 |
| WHO | 6 |
| Kemenkes | 4 |
How a dose is calculated
1. Daily dose
Body weight (kg) × dose (mg/kg/day) = total daily dose.
The catalog always stores doses as mg/kg/day. The “per dose” mode changes how the number is displayed, not the size of the dose.
2. Maximum
If the daily dose exceeds the drug’s ceiling it is capped there and flagged.
86 of 92 drugs carry a daily or single-dose maximum. The app also computes the weight at which that ceiling starts binding, because above it the dose stops following body weight.
3. Dose per administration
Daily dose ÷ frequency = the amount given each time.
4. Volume
Dose per administration ÷ stock concentration (mg/mL) = volume in mL.
Concentration depends on the preparation in your hand, so the catalog stores it for only 37 drugs; you supply the rest.
5. Real preparations
The per-dose amount is translated into what exists: ¼, ½, ¾, 1, 1½ tablets, or a syrup volume.
Because tablets only split at certain fractions, the app shows the dose actually delivered and how far it is from the calculated figure.
Known limitations
Every calculator makes assumptions. These are the ones DoseRx makes.
Rounding of solid forms
Tablets are rounded to splittable fractions, so the delivered dose can land slightly above or below the calculated one. The gap is always shown; liquids are measured continuously and are not rounded.
Weight estimated from age
Uses APLS (0–12 months and 1–10 years) and Luscombe & Owens (>10 years). These are population averages that ignore nutritional status — high for a wasted child, low for an obese one. Weigh the patient where possible.
Compounded powders (puyer)
The calculation assumes the powder mixes evenly and divides equally across sachets. Per-sachet accuracy depends on the compounding itself.
Infusions
Drops per minute assume a giving set of 20 drops/mL (macro) or 60 drops/mL (micro); yours may differ. Each drug's default concentration assumes a specific dilution, which is stated next to the field. The infusion catalog (8 drugs) does not yet cite sources — an acknowledged gap.
Scope
DoseRx is
- a weight-based dose calculation aid
- a dosing reference catalog with its sources named
- a personal tool that runs entirely on your device
DoseRx is not
- a clinical decision support system
- a prescribing or prescription-printing system
- a drug interaction checker
- a complete pharmacy database
- a regulator-certified product
Data & privacy
- No server. Every calculation runs in your browser.
- History, custom presets and favourites live in this device’s localStorage only.
- No analytics, no trackers, no third-party requests — including the font.
- Patient labels are optional; use initials only, never full names.
DoseRx is a calculation aid, not a clinical decision support or prescribing system. Preset dosing values are general references and do not replace clinical judgement. Verify every dose against institutional guidance and current clinical sources before use.