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1.07 Calculating medication dosages

Worksheet
Correct dosages
1

Consider the image below:

Determine the following:

a

The daily dosage for a person older than 12 years of age.

b

Whether this medicine is recommended for children under the age of 12.

2

A patient is prescribed a daily dose of 175 \text{ mg} of aspirin. Their local pharmacy sells tablets containing 350 \text{ mg} of aspirin. How many tablets should a patient take each day?

3

Consider the image below:

Determine the following:

a

The maximum daily dosage for a 15 year old teenager.

b

Whether these tablets are suitable for a 6 year old child.

4

Consider the image below:

Determine the following:

a

The recommended daily dosage for an adult.

b

The youngest age that this medication is recommended for.

5

Consider the image below:

Determine the following:

a

The daily dosage for a 25 year old adult.

b

Whether this medication is recommended for the following people:

i

A 15 year old

ii

An 11 year old

iii

An 18 year old

iv

An 8 year old

6

If the concentration of a drug in a liquid medication is 100 \text{ mg/}12 \text{ mL}, how much of the drug is present in 0.3 \text{ L} of the medication?

7

Some hospital patients may receive medication in liquid form through an intravenous (IV) drip. The required flow rate for the IV drip, in millilitres per hour, is determined using the formula below:

\text{Required flow rate} = \frac{\text{volume (in mL)}}{\text{time (in hours)}}
a

If a patient requires 4.2 \text{ L} of medication over a 12 hour period, calculate the required flow rate in \text{mL/h}.

b

A different patient's IV drip has a flow rate of 500 \text{ mL/h}. If this patient requires a total of 6.25 \text{ L} of medication, over how many hours must the drip be active?

8

Consider the images below:

Determine the following:

a

The maximum recommended daily dosage for a 16 year old teenager.

b

The maximum daily dosage for a 9 year old child.

c

Whether children of the following ages are recommended to take these tablets:

i

6 years old

ii

8 years old

iii

10 years old

iv

4 years old

Correct dosages for children
9

Young's formula, given below, is used to determine the dosage of medicine for children based on their age:

\text{Dosage} = \frac{\text{age of child (in years)} \times \text{adult dosage}}{\text{age of child (in years)} + 12}

a

A twelve year old child has bronchitis and needs augmentin. The normal adult dose is 450 \text{ mg}. Calculate the required dosage for the child correct to the nearest milligram.

b

For a particular drug, the adult daily dosage is 1320 \text{ mg}. A ten year old child is to be given tablets each containing 300 \text{ mg} of the drug. How many tablets should the child take each day?

c

For a different medicine, the adult dosage is 400 \text{ mg }. The correct dosage for a particular child is 160 \text{ mg}. Determine the age of the child, to the nearest year.

10

Clark's formula can be used to calculate the appropriate dosage for children over two years of age based on their mass:

\text{Dosage}=\frac{\text{mass in kg} \times \text{adult dosage}}{70}

a

The adult dosage for a particular medication is 800 \text{ mg} per day.

i

Calculate the dosage for a four year old child with a mass of 40 \text{ kg}. Give your answer correct to the nearest milligram.

ii

Calculate the dosage for a child with a mass of 24 \text{ kg}. Give your answer correct to the nearest milligram.

b

For a particular medicine, the adult dosage is 225\text{ mg} and the correct dosage for a particular child is 45 \text{ mg}. Determine the mass of the child, in kilograms.

11

Fried's formula, given below, is used to determine the dosage of medicine for children based on their age:

\text{Dosage for children 1 - 2 years}=\frac{\text{age in months} \times \text{adult dosage}}{150}

a

A twenty three month old child has asthma and needs prednisolone. The normal adult dose is 200 \text{ mg}. Calculate the required dosage for the child.

b

For a particular medicine, the adult dosage is 350 \text{ mg} and the correct dosage for a particular child is 42 \text{ mg}. Determine the age of the child in months.

c

If the adult dosage of a particular medicine is 200 \text{ mL} and the corresponding child dosage is 20 \text{ mL}, determine the age of the child in months.

12

Below is a table listing the ideal mass for children aged 2 to 12 years.

Use Clarke's formula and the given table to answer the following:

a

An adult is prescribed 500 \text{ mg} of paracetamol. Calculate, to the nearest \text{mg}, the correct dosage for:

i

A 4 year old girl

ii

A 12 year old boy

b

What is the adult dosage of a liquid medicine if the dosage for a 3 year old boy is 220 \text{ mL}?

Age Mass of Males (kg)Mass of Females (kg)
2 12.5 12.0
3 14.0 14.2
4 16.3 15.4
5 18.4 17.9
6 20.6 19.9
7 22.9 22.4
8 25.6 25.8
9 28.6 28.1
10 32.0 31.9
11 35.6 36.9
1239.9 41.5
13

A sixteen month old child has croup and needs prednisolone. The normal adult dose is 200 \text{ mg}.

a

Calculate the required dosage for the child using Fried's formula. Give your answer correct to the nearest milligram.

b

Calculate the required dosage for the child using Young's formula. Give your answer correct to the nearest milligram.

c

Explain the discrepancy in results from the two formulas.

14

A five year old child of mass 16 \text{ kg} has pain and needs ibuprofen. The normal adult dose is 200 \text{ mg}.

a

Calculate the required dosage for the child using Clark's formula. Give your answer correct to the nearest milligram.

b

Calculate the required dosage for the child using Young's formula.

c

Explain the discrepancy in results from the two formulas.

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MS11-6

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