Drug Calculations Using Dimensional Analysis (Vocabulary Flashcards)

Vocabulary flashcards covering key concepts, terms, and rules from drug calculations using dimensional analysis (units, conversions, IV math, weight-based dosing, rounding, and safe dosage concepts).

Dimensional analysis

A calculation method that uses units as factors to convert between measurements and cancel undesired units to arrive at the required unit.

Target (final) unit

The unit of measurement you are solving for in the problem (e.g., capsules per dose, mL per dose).

Conversion factor

A ratio that defines how many of one unit equal another unit, used to cancel units in calculations.

Unit cancellation

The process of multiplying by factors so opposite units cancel out, leaving the desired unit.

Capsules per dose

The number of capsules administered in each dose.

Milliliters per dose (mL/dose)

The volume of medication given per dose expressed in milliliters.

Tablets per dose

The number of tablets administered in each dose.

Drops per minute (gtt/min)

Rate at which IV fluid drops are delivered, measured in drops per minute.

Drop factor (drops/mL)

The number of drops that make up 1 mL for a given IV set; used to convert mL to drops.

Milligrams per day (mg/day)

Total drug amount administered per day in milligrams.

Milligrams per kilogram per day (mg/kg/day)

Dose expressed as milligrams per kilogram of patient weight per day.

Kilogram to pound conversion

Weight conversion where 1 kilogram = 2.2 pounds; used to convert between kg and lb.

Weight-based dosing

Dosing calculated from patient weight (e.g., mg/kg); common in pediatrics.

Safe dosage

A prescribed amount within a defined safe range (e.g., mg/kg/day) that is deemed appropriate.

Lower and upper dosage range

The minimum and maximum limits of a safe dosing range.

mg/kg/day (dosage notation)

Dose expressed as milligrams per kilogram per day; used for weight-based calculations.

Per dose vs per day vs per hour

Per dose: each administration; per day: total daily amount; per hour: rate of administration.

Leading zero

A zero before the decimal point for values less than 1 (e.g., 0.8).

Decimal formatting rules

Leading zeros are required for <1 values; trailing zeros after a decimal point are optional and often omitted.

Rounding rules for IV calculations

Drops per minute must be a whole number; milliliters may be rounded to the nearest tenth when appropriate.

IV flow rate (mL/hour)

The rate to Infuse IV fluids, measured in milliliters per hour.

IV flow calculations (mL to drops)

Use drop factor to convert mL to drops and adjust for time to compute drops per minute.

Order vs supply check

Compare the prescribed dose with what is available (e.g., capsules, tablets) to determine how many units to administer.