M4 · Dosage Calculations¶
This module applies everything from M1–M3 to clinical dosage problems. Every calculation uses dimensional analysis and relies on unit cancellation.
Learning Objectives¶
By the end of this module you should be able to:
- Calculate the correct number of tablets or capsules to administer
- Calculate the correct volume of a liquid medication to administer
- Reconstitute a powder medication and calculate the draw volume
- Calculate weight-based doses for adult and pediatric patients
- Apply a maximum dose check when indicated
- Identify and flag unreasonable answers before administering
- Apply the seven rights of medication administration
Pages¶
Estimated Time¶
Approximately 2–2.5 hours including practice problems.
The Seven Rights¶
Before every medication administration
The Seven Rights are your safety framework regardless of how confident you are in your calculation.
- Right Patient — verify with two identifiers
- Right Medication — check label three times
- Right Dose — calculate and verify
- Right Route — oral, IV, IM, SC, topical
- Right Time — scheduled, PRN, stat
- Right Documentation — chart immediately after
- Right Reason — know why the patient is receiving it
High alert medications
Some medications require independent double-checking by a second nurse regardless of your confidence in the calculation. Common high alert medications include insulin, heparin, warfarin, digoxin, chemotherapy agents, and concentrated electrolytes. Always follow your facility policy.
Skills Used in This Module¶
| Skill | Where you learned it |
|---|---|
| Rounding final answers | M1 — Rounding |
| Converting mg to g, lb to kg | M2 — Metric System, Household Measurements |
| Setting up unit cancellation chains | M2 — Dimensional Analysis |
| Reading stock ratios from labels | M3 — Ratios |
| Reasonableness checks | M3 — Proportions |
Before you begin
Write out every step of every calculation. Do not do mental math for medication calculations. The few seconds saved are never worth the risk.