Module 4 - Dosage Calculations

Overview

Dosage calculation is the direct application of everything covered in Modules 1 through 3. This module focuses on calculating the correct amount of medication to administer across the most common clinical scenarios.

Every calculation in this module uses unit cancellation as the primary method. If any step feels unclear, return to Module 3 before continuing.

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 liquid medication to administer
• Calculate weight-based doses for adult patients
• Calculate weight-based doses for pediatric patients
• Identify and flag unreasonable answers before administering
• Apply the seven rights of medication administration

Topics

• Oral Medications
• Liquid Medications
• Weight-Based Dosing
• Pediatric Dosing

Estimated Time

Approximately 2-2.5 hours including practice problems.

The Seven Rights

Before Every Medication Administration

The Seven Rights are your safety framework for every medication you administer — regardless of how confident you are in your calculation.

1. Right Patient — verify with two identifiers
2. Right Medication — check label three times
3. Right Dose — calculate and verify
4. Right Route — oral, IV, IM, SC, topical
5. Right Time — scheduled, PRN, stat
6. Right Documentation — chart immediately after
7. 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
• Concentrated electrolytes

Always follow your facility policy on double-checking requirements.

Connecting Back to Previous Modules

Skill	Where You Learned It
Rounding final answers	Module 1
Converting mg to g, lb to kg	Module 2
Setting up unit cancellation chains	Module 3
Reading stock ratios from labels	Module 3
Reasonableness checks	Module 3

Before You Begin

Write out every step of every calculation. Do not do mental math for medication calculations — ever. The few seconds saved are never worth the risk.