1
BSc (Hons) & Dip HE Mental Health & Learning
Disabilities Nursing
Numerical
Assessment in
Practice Workbook
Student
Name:
Cohort group:
The purpose of this workbook is to help you practice your
numeracy skills associated with the safe administration of
medication. These are required by the NMC for the
achievement of Practice Learning Outcomes relating to
competence in numeracy and calculation. This workbook
may be used as supportive evidence of your preparation
and therefore can be used in your discussions with your
assessor.
2
Advice to Students
Work your way through this workbook, working on the practice
questions as you go. The answers are provided but try not to look
at them before you have completed the exercises. Always show
how you have worked out a particular question – this helps you
identify any errors you might make and could help you and your
assessor understand how you have arrived at the answer.
Try wherever possible not to rely on using a calculator. By working
things out on paper and using your own numeracy skills you are
more likely to be able to spot where an answer seems to be wrong
– for example, you know ‘in your head’ that the answer is likely to
be 3 tablets and yet the calculator answer suggests 12.
Safe Administration of Medicines - Guidance for Students
The NMC Guide for Students of Nursing & Midwifery (April 2002)
reminds you that:
“During your studentship, you will come into close contact with
patients or clients. This may be through observing care being
given, through helping in providing care and, later, through full
participation in providing care. At all times, you should work only
within your level of understanding and competence, and always
under the appropriate supervision of a registered nurse or midwife,
or a health professional with a registered nurse or midwife
providing mentorship.”(available from www.nmc-uk.org.)
You must ensure that you follow the policies and guidelines of your
placement trust. If you are uncertain of your role and
responsibilities relating to any aspect of the safe administration of
medication that you seek advice from a qualified member of
nursing staff or your mentor.
Further sources of support
Whilst you are on practice you may also contact the designated
pharmacist for your practice area for additional advice, guidance
and information.
3
The Metric System
Weight
1 kilogram
1 gram
1 milligram
=
=
=
1000 grams
1000 milligrams
1000 micrograms
1 microgram =
1 nanogram =
1000 nanograms
1000 picograms
Recognised abbreviations of these units are:
kilogram = kg
microgram = mcg
gram = g
nanogram = ng
milligram = mg
(Abbreviations for microgram and nanogram should not be used in
prescribing.)
Volume
1 litre
=
1000 millilitres
Recognised abbreviations of these units are:
litre = L
millilitre = ml
Strength of a solution
This can be expressed as:
a) % weight versus volume = number of grams per 100mls
e.g. sodium chloride 30% = 30g in 100mls
b) Parts e.g. Adrenaline 1 in 1000 = 1g in 1000ml = 1mg in 1ml
Adrenaline 1 in 10,000 = 1g in 10,000ml = 1mg in 10mls
4
Converting Larger Units to the Next Smaller Unit
To convert a larger unit to a smaller unit you need to multiply by 1000.
Example:
Convert 5g to milligrams:
Convert 0.25kg to grams:
5 x 1000
0.25 x 1000
=
=
5000mg
250g
Practice:
Convert the following to micrograms
1. 0.5mg
2. 0.0625mg
3. 0.25 mg
Convert the following into nanograms
4 0.25 mcg
5 0.0625 mcg
6 1.5mcg
Converting smaller units to the next larger unit:
To convert a smaller unit to the larger unit you divide by 1000.
Example:
Convert 6000g to kilograms :
Convert 325mg to grams:
6000/ 1000 =
325/ 1000
=
Practice:
Convert the following into milligrams
7 300mcg
8 75mcg
9 187.5 mcg
6kg
0.325g
5
Dealing with Decimal Points
25
x 0.5
____
12.5
25
x 0.05
_____
1.25
There is one number
after the decimal point
in the sum therefore one
after the point in the answer.
There are two numbers
after the decimal point
in the sum therefore two
after the point in the answer.
Practice
10.
2.5 x 100 =
11.
0.3 x1000 =
12.
7.5 x 30
13.
36  60 =
14.
125 550 = (calculate to 2 decimal places)
=
15. 5.5  50 =
16.
250  1000 =
6
Fractions
To simplify fractions divide the top number into the bottom number, which
divides into both of these exactly.
This number is called a common factor.
e.g.
24 = 2
36
3
(both numbers have been divided by 12, which is a common factor used
in this fraction.)
This could also have been completed in several steps:
24
36
= 12
18
(common factor is 2)
= 4
6
(common factor is 3)
= 2
3
(common factor 2)
Then
12
18
Then
4
6
Converting fractions to decimals
In order to convert a fraction to a decimal, you need to divide the top number
by the bottom number.
e.g.
1 =
2
2
(divide the top number by the bottom one)
0.5
1.0
= 0.5
Practice
17.
3
9
21.
3 =
4
=
18.
22.
6 =
2
1
100
19.
=
25 =
75
20.
7 =
8
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Fluid Requirements
First 10kg
= 100ml/kg
Second 10kg
= 50ml/kg
Subsequent
= 20ml/kg
Practice:
Using the above formula calculate the daily fluid requirements
23. 6.2kg
24. 3.8kg
25. 29kg
Unit conversion
26.
4000 micrograms =
2 litres =
mg
ml
6mg
=
0.24 micrograms =
micrograms
nanograms
75 mg =
grams
187.5 micrograms =
mg
650 ml =
litres
0.25 micrograms =
nanograms
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Oral Liquids
Triclofos is a sedative produced in concentration of 500mg/5mls. Calculate
the volumes for the following doses:
27.
Dose Prescribed (mg)
250
350
65
150
750
Volume Required (ml)
Ranitidine comes in a concentration of 150mg in 10mls; calculate the volumes
needed for the following doses:
28.
Dose Prescribed (mg)
25
16
35
65
150
Volume Required (ml)
Drug Dosages for Injection
Volume Required = Dose prescribed
Dose you have
available
x
volume of stock solution
e.g.
A patient is prescribed cortisone 40 mg. The ampoules contain 50 mg in 2mls.
Calculate the volume required.
Using the formula
40 mg x 2ml
50mg
= 40 x 2
9
50
Answer =
8
5
1
= 1.6 mls
Practice
29. If 50 mg of a drug is contained in 10ml of solution, how much must be
given to give 25mg?
30. Prescribed: Erythromycin 270 mg
Available:
300mg in 10 mls
31 Morphine 9 mg is required and the stock solution is 15mg in 1 ml. How
much is required?
32. The ampoule reads 500micrograms in 5 mls of solution. How much
solution is needed to give 10 micrograms?
More Practice Questions:
Q1.
Mellisa Wayfield is due to be discharged from the unit where you are working.
She has been prescribed Paroxetine 40mgs daily for her feelings of panic.
These are dispensed as 20mg tablets and she will need enough tablets for 4
weeks.
(a)
How many 20mg tablets will need to be dispensed?
a)
Paroxetine is available in packs of 15 tablets per pack. How many
whole packs should be in her discharge medication?
10
Q2.
David, who has a bi-polar disorder, is going through a period of significant
depression and there is some concern that his fluid balance is not being well
maintained (see chart below for details).
a) Complete this table to give the daily total for both intake and output
FLUID INTAKE (millilitres)
TIME
3rd March
4th March
5th March
08:00
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
17:00
18:00
19:00
300
300
250
DAY
TOTALS
20:00
21:00
22:00
23:00
00:00
01:00
02:00
03:00
04:00
05:00
06:00
07:00
FLUID OUTPUT (millilitres)
6th March 3rd March 4th March 5th March. 6th March
250
280
280
230
250
250
125
135
225
300
135
133
240
300
250
175
220
370
270
140
152
200
230
270
250
525
225
250
300
450
330
125
100
380
150
350
320
400
300
NIGHT
TOTALS
24 HOUR
TOTALS
b) What is David’s average daily fluid intake over these 4 days?
345
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c) What is David’s average daily fluid output over these 4 days?
David is thought to be developing a chest infection, so 400mg of an antibiotic
is prescribed, to be administered 6-hourly. The antibiotic comes in a
suspension of 125mg in 5 ml.
d) How many ml will be needed for all doses over a 24-hour period?
David is being treated with Lithium Citrate in order to help him control his
mood. Currently he is being given that in liquid form and it comes in a
suspension which contains 520mg/5mls. He is prescribed 2.6 g daily to be
given in 2 evenly divided doses
e) How many millilitres should be given in each dose?
Now David has recovered a little and it has been decided to return him to the
tablet form of Lithium Carbonate. The pharmacy is preparing a bottle of
tablets for David to take away with him for a weekend break. The tablets
come in 200 mg. David is prescribed 0.6 grams twice daily.
f) If David is going away for 3 days how many tablets does the pharmacist
need to dispense for his trip?
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g) David actually returned home early after 2 days. How many tablets should
be left in his drug bottle?
Q3.
Susan has regular epileptic seizures but these are reasonably controlled
through the use of medication. Currently she is prescribed Phenytoin in a
suspension which contains 15mg/2.5ml. The initial dose is worked out
according to body weight (3.5mg per kg daily).
a) If Susan is 86kg what would her initial daily dose be (to the nearest 10mg)?
Because Susan’s epilepsy is now generally well-controlled she is actually
prescribed 255 mg Phenytoin a day to be given in 2 equal doses.
b) How many millilitres of suspension should be given in each dose?
Susan then has a bout of flu and this interferes with her ability to control her
seizures. She enters a state of Status Epilepticus and requires Diazepam
rectal solution to be administered. She is prescribed 30 mg as a one off dose
to be repeated after 12 hours if necessary. Rectal tubes contain 4mg per ml
and come in 2.5 ml tubes.
c) How many tubes are required for that first treatment?
Q.4
Zuclopenthixol Acetate (Clopixol Acuphase) is administered by injection for
the treatment and management of acute psychosis, mania or exacerbations of
chronic psychosis. Ben Yuhuru has exhibited increasingly impulsive and
dangerous behaviour over the past 24 hour period, placing others at
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considerable risk. He is prescribed Clopixol Acuphase 150mgs by deep
muscular injection.
a) Clopixol Acuphase is available in ampoules of 50mgs in 1ml liquid
suspension. How many ampoules will need to be drawn up for the
correct dose to be given?
b) He is prescribed a further injection after 2 days of the same dose of
Clopixol Acuphase after the first injection was given and another
injection 1 day later of a reduced dose of 100mg. The maximum
accumulative dose should not exceed 400mgs over the course of a
few days, has this been exceeded?
c) How many ampoules have been used in total?
Q5.
Stephen Wilson, a service user has become very distressed and aggressive
on the unit. He is at risk of harming himself and of harming other people. It
has been decided by the team that for his own safety and for the safety of
others he will need to have an injection of lorazepam. The medicine card
indicates that a 2mg dose should be given. Lorazepam is available as 4mg/ml
solution in 1ml ampoules, and it should be diluted with an equal volume of
water for injection.
a) What volume of lorazepam injection is needed?
b) Once this is diluted with an equal amount of water what will be the total
volume in the syringe?
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Answers to Practice Questions
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
500 micrograms
62.5 micrograms
250 micrograms
250 nanograms
62.5 nanograms
1500 nanograms
0.3 mgs
0.075 mgs
0.1875 mgs
250
300
225
0.6
0.23
0.11
0.25
0.333
3
0.333
0.875
0.75
0.01
620 mls
380 mls
1680 mls
26.
4000 micrograms = 4 mg
6mg
= 6000 micrograms
2 litres = 2000ml
0.24 micrograms = 240 nanograms
75 mg = 0.075grams
187.5 micrograms = 0.1875 mg
650 ml = 0.65 litres
0.25 micrograms = 250 nanograms
15
27.
Dose Prescribed (mg)
250
350
65
150
750
Volume Required (ml)
2.5
3.5
0.65
1.5
7.5
28.
Dose Prescribed (mg)
25
16
35
65
150
29
30
31
32
Volume Required (ml)
1.66
1.066
2.33
4.33
10
5 mls
9 mls
0.6 mls
0.1 mls
Answers to More Practice Questions
Q1. Mellisa Wayfield is due to be discharged from the unit where you are
working. She has been prescribed Paroxetine 40mgs daily for her feelings of
panic. These are dispensed as 20mg tablets and she will need enough tablets
for 4 weeks.
(a) How many 20mg tablets will need to be dispensed? 56 tablets
b)
Paroxetine is available in packs of 15 tablets per pack. How many
whole packs should be in her discharge medication?
4 whole packs
16
2. a) Complete this table to give the daily total for both intake and output
FLUID INTAKE (millilitres)
TIME
3rd March
4th March
5th March
08:00
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
17:00
18:00
19:00
300
300
250
DAY
TOTALS
20:00
21:00
22:00
23:00
00:00
01:00
02:00
03:00
04:00
05:00
06:00
07:00
FLUID OUTPUT (millilitres)
6th March 3rd March 4th March 5th March. 6th March
250
280
280
230
250
250
125
135
225
300
135
133
240
270
140
152
200
300
250
175
220
370
230
270
250
525
225
250
300
1645
925
920
1215
950
450
695
330
700
125
100
760
380
150
350
320
400
300
NIGHT
TOTALS
0 average100
125 over these
150
What is David’s
daily fluid intake
4 days? 850
630
670
725
24 HOUR
TOTALS
1270ml
1325
1370
1485
1645
1025
1045
1365
1800
What is David’s average daily fluid output over these 4 days 1495ml
b) What is David’s average daily fluid intake over these 4 days?
1270 ml
c) What is David’s average daily fluid output over these 4 days?
1495 ml
345
17
David is thought to be developing a chest infection, so 400mg of an antibiotic
is prescribed, to be administered 6-hourly. The antibiotic comes in a
suspension of 125mg in 5 ml. How many ml will be needed for all doses over
a 24-hour period? 64ml
David is being treated with Lithium Citrate in order to help him control his
mood. Currently he is being given that in liquid form and it comes in a
suspension which contains 520mg/5mls. He is prescribed 2.6 g daily to be
given in 2 evenly divided doses How many millilitres should be given in each
dose.
12.5ml
Now David has recovered a little and it has been decided to return him to the
tablet form of Lithium Carbonate. The pharmacy is preparing a bottle of
tablets for David to take away with her for a weekend break. The tablets
come in 200 mg. David is prescribed 0.6 grams twice daily. If David is going
away for 3 days how many tablets does the pharmacist need to dispense for
his trip?
18 tablets
David actually returned home early after 2 days. How many tablets should be
left in his drug bottle?
6 tablets
Q3.
Susan has regular epileptic seizures but these are reasonably controlled
through the use of medication. Currently she is prescribed Phenytoin in a
suspension which contains 15mg/2.5ml. The initial dose is worked out
according to body weight (3.5mg per kg daily). If Susan is 86kg what would
her initial daily dose be (to the nearest 10mg)? 300mg
Because Susan’s epilepsy is now generally well-controlled she is actually
prescribed 255 mg Phenytoin a day to be given in 2 equal doses. How many
millilitres of suspension should be given in each dose?
21.25ml
Susan then has a bout of flu and this interferes with her ability to control her
seizures. She enters a state of Status Epilepticus and requires Diazepam
rectal solution to be administered. She is prescribed 30 mg as a one off dose
to be repeated after 12 hours if necessary. Rectal tubes contain 4mg per ml
and come in 2.5 ml tubes. How many tubes are required for that first
treatment?
3 tubes
Q4.
Zuclopenthixol Acetate (Clopixol Acuphase) is administered by injection for
the treatment and management of acute psychosis, mania or exacerbations of
18
chronic psychosis. Ben Yuhuru has exhibited increasingly impulsive and
dangerous behaviour over the past 24 hour period, placing others at
considerable risk. He is prescribed Clopixol Acuphase 150mgs by deep
muscular injection.
(a) Clopixol Acuphase is available in ampoules of 50mgs in 1ml liquid
suspension. How many ampoules will need to be drawn up for the correct
dose to be given?
3 ampoules
(b) He is prescribed a further injection 2 days of the same dose of Clopixol
Acuphase after the first injection was given and another injection 1 day
later of a reduced dose of 100mg. The maximum accumulative dose
should not exceed 400mgs over the course of a few days, has this been
exceeded? No
(c) How many ampoules have been used in total? 8 ampoules
Q5.
Stephen Wilson, a service user, has become very distressed and aggressive
on the unit. He is at risk of harming himself and of harming other people. It
has been decided by the team that for his own safety and for the safety of
others he will need to have an injection of lorazepam. The medicine card
indicates that a 2mg dose should be given. Lorazepam is available as 4mg/ml
solution in 1ml ampoules, and it should be diluted with an equal volume of
water for injection.
c) What volume of lorazepam injection is needed? 0.5ml lorazepam is
needed
d)
Once this is diluted with an equal amount of water what will be
the total volume in the syringe? 0.5ml lorazepam + an equal volume of
water will give a total of 1ml in the syringe