Dosing and calculation

Question 1

Answer 1

Question 2

Answer 2

Question 3

What unotes should doses be written for paediatrics (& all?)

Answer 3

Mg unless otherwise specified in the BNF

Question 4

How do you calculate lean body weight? [1]

Answer 4

Body fat weight - actual body weight

Question 5

In paedatriac intermediate life support, how should you calculate babys weight? [1]

Answer 5

(Age + 4) x 2 (kg)

Question 6

what does ‘%w/w’ mean? [1]

Answer 6

Question 7

what does ‘%v/v’ mean? [1]

Answer 7

Question 7

Explain what ‘%w/v’ means? [1]

Answer 7

Question 8

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Question 9

Answer 9

Question 10

Calculate how much sodium bicarbonate is in the following preparation:

’ Sodium bicarbonate 8.4% w/v 100ml’

Answer 10

An 8.4% solution contrains 8.4g in 100ml

Question 11

How much MgS is in:

‘Magnesium sulfate 20% w/v 20ml ampoule for injection’

Answer 11

Question 12

Explain how ratios can be used to express drug calculations [2].

Answer 12

1:1000 = 1g in 1000ml
- 1g in 1000ml = 1000mg in 1000ml = 1mg in 1ml

1:10 000 = 1 g in 10 000ml
- 1g in 10,000ml = 1000mg in 10,000ml = 1mg in 10ml = 100microgram in 1ml

Question 13

Answer 13

Question 14

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Question 15

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Question 16

Answer 16

Question 17

Answer 17

Question 18

Answer 18

In the BNF:
‘Child 3–5 months: 60 mg every 4–6 hours; maximum 4 doses per day”

Therefore max dose: 60x4 = 240mg

Question 19

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Question 20

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Question 21

Answer 21

Question 22

What is the standard practise when withdrawing benzodiazepine medication?

Answer 22

Change benzo to equivalent dose of diazepam then carefull reduce the dose of this to zero

Question 23

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Question 24

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Question 25

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Question 26

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Question 27

Answer 27

Question 28

He takes 40mg twice a day morphine sulfate. He also takes 20mg morphine sulfate daily PRN. Covert his 24hr dose of morphine sulfate to a fentanyl patch Fentanyl 25 micrograms/ hr patch Fentanyl 37 micrograms/ hr patch Fentanyl 50 micrograms/ hr patch Fentanyl 100 micrograms/ hr patch

Answer 28

He takes 40mg twice a day morphine sulfate. He also takes 20mg morphine sulfate daily PRN. Covert his 24hr dose of morphine sulfate to a fentanyl patch Fentanyl 25 micrograms/ hr patch **Fentanyl 37 micrograms/ hr patch** Fentanyl 50 micrograms/ hr patch Fentanyl 100 micrograms/ hr patch

Question 29

Convert his oral morphine sulfate to diamorphine via sub infusion

Question 30

What should vancomycin be diluted to a concentration of when dosing? [1] What should the infusion rate not exceed? [1]

Answer 30

**5mg/ml** Should not exceed **10mg/minutes**

Question 31

You need to prescribe 1 gram of vancomycin. Describe how you decide what size infusion bag you would use [1] | NB: Vancomycin is infused at 5mg/ml

Answer 31

1 g = 1000 mg Need to dilute to 5mg/ml Therefore 1000 mg in 1000 ml = 1mg/ml But we want 5mg/ml so divide 1000ml by 5 = 200ml BUT bags only come in 250ml

Question 32

State how you would prescribe the correct infusion rate for vancomycin

Answer 32

Question 33

What are the steps need to enact when prescribing NAC infusion? [4]

Answer 33

1. **Find out actual body weight**: max weight should use is 110kg 2. **Add with glucose 5%** 3. **The total dose regimen is to be prescribed and adminstered in three parts**: - First (loading) dose is given over 1hr in 200ml of glucose 5% - Second dose given over the next 4hrs, in 500ml of glucose 5% - The third and final is given over 16hrs, 1 litre of glucose 5% 4. **Those dose of NAC varies at each steps:** - For the first you need 150 mg/kg - For the second you need 50 mg/kh - For the third you need 100 mg / kg - Thats a total dose of 300 mg/kg over 21 hrs! | Look Up in BNF: Poisoning, emergency treatment

Question 34

Answer 34

## Footnote Look up BNF xx

Question 35

Answer 35

Question 36

Answer 36

Question 37

Answer 37

Question 38

How do you calculate volume required of a paraenteral drug? [1]

Answer 38

Vol = (Dose prescribed x vol of solution) / amount of drug in solution (same as vol required = what you want / waht youve got) x whats in it

Question 39

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Question 40

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Question 41

Answer 41