3 Weight-Based Dosing and Safe Dose Ranges Free Online FlashCards

How do you convert a weight in pounds to kilograms?

Convert pounds to kilograms using $\mathrm{kg}=\frac{\mathrm{lb}}{2.2}$. Confirm the weight units and calculated value.

What is one dose at $5\,\mathrm{mg/kg/dose}$ for a patient weighing $18\,\mathrm{kg}$?

For one dose, multiply weight by the prescribed amount per kilogram: $18\,\mathrm{kg}\times5\,\frac{\mathrm{mg}}{\mathrm{kg}\cdot\mathrm{dose}}=90\,\mathrm{mg/dose}$.

Does an every-$8$-hour schedule change the single-dose multiplication?

The frequency is the schedule, not part of the single-dose multiplication. Calculate the amount for one dose first, then apply the prescribed schedule.

How do you calculate a total daily dose from $\mathrm{mg/kg/day}$?

First calculate the total for the day: $\mathrm{total\ daily\ dose}=\mathrm{weight\ (kg)}\times\mathrm{prescribed\ mg/kg/day}$. Divide by doses per day only if the daily amount is divided.

How many doses per day does an every-$8$-hour schedule indicate?

There are $24\div8=3$ doses in $24$ hours, so an every-$8$-hour schedule means $3$ doses per day.

For $15\,\mathrm{mg/kg/day}$ at $18\,\mathrm{kg}$, divided every $8$ hours, what is each dose?

The daily total is $18\,\mathrm{kg}\times15\,\mathrm{mg/kg/day}=270\,\mathrm{mg/day}$. With $3$ equal doses daily, each dose is $270\div3=90\,\mathrm{mg}$.

What is the key difference between $\mathrm{mg/kg/dose}$ and $\mathrm{mg/kg/day}$?

They are not interchangeable: $\mathrm{mg/kg/dose}$ specifies an amount for each dose, while $\mathrm{mg/kg/day}$ specifies a total for the day. Applying a daily amount to every dose can cause a major error.

What determines which medication safe-dose range applies?

Use a current, reliable reference for the specific medication, indication, route, age, and dosing schedule. A safe range cannot be inferred from weight alone.

At $18\,\mathrm{kg}$, what range corresponds to $4$–$6\,\mathrm{mg/kg/dose}$?

Multiply the weight by both ends of the range: $18\times4=72\,\mathrm{mg/dose}$ and $18\times6=108\,\mathrm{mg/dose}$. The patient-specific range is $72$–$108\,\mathrm{mg/dose}$.

What daily maximum corresponds to $18\,\mathrm{mg/kg/day}$ for $18\,\mathrm{kg}$?

Multiply the weight by the daily limit: $18\,\mathrm{kg}\times18\,\mathrm{mg/kg/day}=324\,\mathrm{mg/day}$.

If a $324\,\mathrm{mg/day}$ maximum is divided into $3$ equal doses, what is the maximum per dose?

Divide the daily maximum by the number of equal daily doses: $324\,\mathrm{mg/day}\div3=108\,\mathrm{mg/dose}$.

How should a calculated dose be compared with a reference range?

Compare like with like: a dose per administration against a per-dose range, or a total daily amount against a daily range.