LPN INTENSIVE CALCULATIONS�� PROGRESS TEST 2 ��� INTENSIVE GPHC Exam revision � programme FOR NOV 25
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QUESTION 1
A-60-year-old male weighing 85kg with AF is admitted to hospital and needs to be prescribed digoxin. His creatinine clearance is 40ml/min. The doctor prescribes a dose of digoxin to be administered orally twice a day . The target peak concentration for him is 1.5mcg/L . Calculate which strength of tablets the doctor should prescribe for this patient . His height is 5ft 11 inches.
CHOICES - 62.5 mcg tablets , 125mcg tablets or 250mcg tablets
CPss = F X S X D
CL x T
CL = 0.053 x CrCl + (0.02 x IBW )
F = bioavailability 0.9 , D = dose (mg) , CL = clearance, T = dosage interval (hours) , S = Salt factor 1, IBW = 60.5kg
ANSWER 1
CPss = F X S X D
CL x T
1.5 = 0.9 x 1 x D
3.33 x12 hrs.
= 66.6mcg DECISION MAKING
Round due to tablets strengths available.
ANSWER = 62.5mcg
QUESTION 2
You work as a hospital pharmacist in a renal transplant unit. A 10-year-old female patient was prescribed tacrolimus 5mg/ml solution for infusion for the Prophylaxis of kidney transplant rejection. The child weighs 33kg and is prescribed a dose of 0.05mg/kg/day as continuous 24-hour infusion. To reduce the risk of side-effects the infusion is to be prepared to the minimum recommended concentration using a suitable diluent.
The resource is provided below. section 6.6
Calculate the infusion rate in ml/min. Answer to 1 d.p.
London Pharmacist Network intensive GPhc exam calculations
ANSWER 2
ANSWER 2
0.05mg/kg/day . 0.05 x 33kg = 1.65mg
Minimum concentration = 0.004mg/ml
Hence 1.65mg = 412.5ml
412.5ml = 24 hours
17.1875ml = 1 hour
0.286458ml = 1 minute
ANSWER = 0.3ml/minute
QUESTION 3
An elderly patient takes Acidex oral suspension for heartburn and indigestion. However, his doctor is concerned about his sodium intake levels. He takes 10ml of Acidex oral suspension with his breakfast, with lunch and dinner. Given that each 5ml of Acidex oral suspension contains 133.5mg of sodium bicarbonate, Calculate the percentage of his sodium RDA he takes via a daily dose of Acidex. Answer the nearest whole number.
NB
RDA of sodium = 2.4g (6g of salt)
Sodium bicarbonate = NaHC03
Na = 23, H = 1, C = 12, O = 16
London Pharmacist Network intensive GPhc exam calculations
ANSWER 3
5ml of Acidex oral suspension contains 133.5mg of sodium bicarbonate
30ml per day = 801mg of sodium bicarbonate
Mmol = mass/ Mr
Mmol = 801 / 84 = 9.5357mmol
9.5357 x 23 = 219.3211mg
219.32/ 2400 x 100 = 9.138
ANSWER = 9%
QUESTION 4
Grace is a 3-month-old child weighing 12.1kg. The doctor has prescribed omeprazole 2mg/ml oral suspension sugar free at a dose of 0.65mg/kg/day using a 5ML syringe as shown in the picture underneath. Calculate the volume Grace will use in a month (28 days).
ANSWER in ml to 1.d.p
UK’s most INTENSIVE GPhC exam calculations
ANSWER 4
0.65mg/kg/day
0.65 X 12.1mg = 7.865mg per day
2mg = 1ml
7.865 = 3.9325ml
ROUND TO NEAREST 0.1ml as per syringe marking
3.9 x 28 = 109.2
ANSWER = 109.2ml
QUESTION 5 – Dose tapering
A patient is transitioning from Sertraline 100 mg once daily to Duloxetine 60 mg once daily, following the recommended cross-tapering schedule: You only have 50mg sertraline tablets in stock. How many Sertraline 50mg tablets will you supply?
Week 1: Reduce Sertraline to 75 mg once daily, introduce Duloxetine 20 mg once daily.
Week 2: Reduce Sertraline to 50mg once daily, increase Duloxetine to 40 mg once daily.
Week 3: Reduce Sertraline to 25 mg once daily, increase Duloxetine to 50 mg once daily.
Week 4: Stop Sertraline, increase Duloxetine to 60 mg once daily.
SEE TABLE ON NEXT PAGE
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ANSWER 5
WEEK 1 = 1.5 tabs x 7 days
WEEK 2 = 1 tabs x 7 days
WEEK 3 = 0.5 tabs x 7 days
TOTAL = 21 TABLETS
ANSWER = 21 TABLETS
QUESTION 6
Mr. H., a 71-year-old patient has been taking Alprazolam 500mcg three times daily for 9 months. His doctor would like to wean him off alprazolam tablets using diazepam 5mg tablets. You are required to Switch his weekly dose to diazepam equivalent then calculate how many tablets of diazepam 5mg you would supply to Mr. H given that his dose will be reduced by Diazepam 5mg each week until completion.
London Pharmacist Network intensive GPhc exam calculations
ANSWER 6
Alprazolam 250mcg = 5mg of diazepam
Patient takes 1500mcg daily = 30mg diazepam (6 tablets)
WEEK 1 = 6 tabs x 7 days
WEEK 2 = 5 tabs x 7 days
WEEK 3 = 4 tabs x 7 days
WEEK 4 = 3 tabs x 7 days
WEEK 5 = 2 tabs x 7 days
WEEK 6 = 1 tabs x 7 days
TOTAL = 147
ANSWER = 147 Tablets
QUESTION 7
You work as a pharmacist in a hospital on the geriatric ward. An elderly patient is prescribed an antibiotic via intravenous infusion at a dose of 7mg/kg/min . The patient weighs 180 lbs. and is 182cm tall. You have the drug available at a concentration of 0.1g/10ml solution.
1lb = 0.45kg
Use the information provided to calculate the infusion rate for this patient in Litre /hour.
State your answer to nearest 0.5 .
QUESTION 7 ANSWER
180 lbs. = 81kg
7mg x 81kg = 567mg per min
567mg x 60 mins = 34,020mg
If 0.1g = 10ml
Then 34.02g = 3402ml
ANSWER = 3.5L/hour
QUESTION 8
You work as a pharmacist in a community pharmacy. A female presents a prescription for herself. Phenoxymethylpenicillin 1g QDS for ten days.
You have 100ml bottles of phenoxymethylpenicillin 125mg/5ml suspension powder in stock.
You realize that the drug expires 7 days after reconstitution. The patient is happy to take 5 days treatment today and return for the rest later.
How many bottles would you supply today?
State your answer as whole number.
QUESTION 8 ANSWER
40ml phenoxymethylpenicillin 125mg/5ml suspension QDS for 10 days.
40ml x 4 = 160ml
160ml needed daily.
For 5 days = 800ml
ANSWER = 8 bottles
QUESTION 9
You are required to mix four glucose solutions together.
Solution A - 300ml of glucose 5% solution
Solution B – 500ml of glucose 12.5% solution
Solution C – 700ml of glucose 7.5% solution
Solution D – 400ml of glucose 3.5% solution
Calculate the concentration of the resulting solution.
Give your answer in %w/v to the nearest 0.1.
ANSWER 9
QUESTION 10
Mr. and Mrs. Okabo and their son who regularly use your pharmacy will be travelling from the UK to France for a week then from France to Uganda for 5 weeks before travelling back to the UK. After a brief consultation, you are required to supply Mefloquine for malaria prophylaxis. You only have 5 tablets of mefloquine in stock. Mr. Adams weighs 71kg , Mrs. Okabo weighs 65kg and their son weighs 30kg.
Specifically using the resource provided on next page, calculate the quantity of tablets to be supplied and state your answer as how many tablets owed?
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ANSWER 10
QUESTION 11
You work on an aseptic ward at a hospital.
A patient requires an antiseptic solution for wound dressing.
You need to prepare 300ml of an antiseptic solution such that when diluted 1 in 25 by the patient they will have a 1000ppm solution to use.
Your stock is 5 litres of 20%w/v solution.
What volume of this stock in ml should be used?
Answer to 1.d.p.
London Pharmacist Network intensive GPhc exam calculations
ANSWER 11
1000 ppm = 0.1%w/v
Initial conc = FC X DF --- 0.1 X 25 = 2.5%w/v
C1V1 = C2V2
20 X V1 = 2.5 X 300
V1 = 750/20
V1= 37.5ml
QUESTION 12 – Synchronize a prescription
Mrs. G. a 71-year-old female would like you to synchronize one of her medication. She currently has a stock of:-
56 metformin 500mg tabs - take one twice daily, 28 Atorvastatin 20mg - take one daily, 42 Levothyroxine 50mcg tabs - take one every morning, 14 levothyroxine 25mcg tabs - take one on alternate mornings and 24 methotrexate 2.5mg tablets - Take 10mg every week.
The patient would like you to synchronize levothyroxine 25mcg tablets. How many tablets would she need to synchronize?
London Pharmacist Network intensive GPhc exam calculations
ANSWER 12
Highest = methotrexate 2.5mg = 6 weeks (42 days)
Levothyroxine 25mcg = 14 tabs on alternates days = 28 days
42 days – 28 days = 14 days
7 tablets needed as she takes on alternate days
ANSWER = 7 TABLETS
QUESTION 13
Mr. Ken is to receive an IV infusion.
The doctor has prescribed a dose of 5ml/minute.
The infusion bag contains
NacL - 21 mmol/Litre
Cacl - 32mmol/ litre
NaHCO3 - 42mmol/Litre
Glucose - 5 mmol/Litre
Calculate the total amount of sodium he would receive after 1 hour of the infusion.
Answer in gram to 1.d.p.
Na = 23 Cl=35.5 H= 1 C= 12 O = 16 Ca = 40
London Pharmacist Network intensive GPhc exam calculations
ANSWER 13
NacL = 58.5g/mol
5ml per min . So, 300ml per hour
NacL 21mmol = 1000ml (1 litre) So,6.3mmol = 300ml
6.3mmol x 23 = 144.9mg of sodium
NaHC03 = 84g/mol
5ml per min. So, 300ml per hour
NaHCO3 42mmol = 1000ml (1 litre) So, 12.6 = 300ml
12.6mmol x 23 = 289.8mg of sodium
TOTAL = 434.7mg .
IN gram = 0.4g ANSWER
QUESTION 14
Mr. Raj weighs 65kg and is prescribed morphine via IV infusion at a dose of 1.25mg/kg/hour. Morphine is available as 10mg/ml concentrate. The nurse is required to dilute morphine to 3mg/ml using glucose 5%w/v solution, prior to infusion.
Calculate the infusion rate in ml/minute for Mr. Raj.
Answer to nearest 0.5.
London Pharmacist Network intensive GPhc exam calculations
ANSWER 14
1.25mg x 65kg = 81.25mg
Diluted to, 3mg = 1ml
81.25mg = 27.83ml
27.83ml = 60 minutes ( 1 hour)
0.4638ml = 1 minute
ANSWER = 0.5ml/min
QUESTION 15
Ms. Z is a pregnant female in labour and requires levobupivacaine 5mg/ml as epidural. The doctor recommends a dose of 500mcg/kg/min for 18 minutes. Before administration, the drug should be diluted to a concentration of 0.2mg/ml using sodium chloride 0.9% w/v. Calculate the volume of sodium chloride required to dilute the recommended amount of levobupivacaine for the entire treatment.
Patient's height is 5 ft''7 inches and weight is 200lbs.
1 foot = 30.48cm 1 inch = 2.54cm and 1lb = 0.45kg
Answer in ml as a whole number.
London Pharmacist Network intensive GPhc exam calculations
ANSWER 15
500mcg x 90 x 18 = 810000mcg i.e., 810mg
Levobupivacaine 5mg/ml
810mg = 162ml
After dilution, concentration = 0.2mg/ml
Hence ; 810mg = 4050ml
4050ml – 162ml = 3888ml
ANSWER = 3888ml
QUESTION 16
Andrew a 19-year-old student is keen to lose weight and has hired a personal trainer at the local gym. He currently weighs 12 stone and 7lb and is 165cm tall. Calculate how much weight in Kg, Andrew needs to lose in order to reach a body mass index of 24.9kg/m2.
Give your final answer to nearest 0.5kg.
1 STONE = 6.35KG and 1 lb = 0.45kg
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ANSWER 16
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QUESTION 17
A 75kg patient is prescribed Gentamicin 80mg/2ml bolus injection. At 8am today, he is prescribed a loading dose of 3mg/kg via bolus injection this will be followed by maintenance doses of 1.5mg/kg every 12 hours. Given that the first maintenance dose will be administered 24 hours after the loading dose, calculate the total volume of gentamicin the patient would receive after six doses of her entire treatment.
Answer in ml as whole number.
UK’s most INTENSIVE GPhC exam calculations
ANSWER 17
Gentamicin 80mg = 2ml
TOTAL = 19.6875ml
ANSWER = 20ml
QUESTION 18
You receive a prescription for Co-beneldopa capsules 12.5mg/ 50mg.
Take one capsule four times a day then increase in steps of 12.5mg/50mg every week until a maintenance dose of 200mg of levodopa is reached, then continue for 3 weeks.
How many Co-beneldopa 12.5mg/ 50mg capsules would you supply for this prescription.
London Pharmacist Network intensive GPhc exam calculations
ANSWER 18
QUESTION 19
You have a 1000ml stock solution of 25%w/v strength when diluted 1 in 20 by the patient, produced an intermediate strength solution .
What volume of the intermediate solution is required to make a 1000ppm of a 100ml final solution.
Give your answer as whole number ?
London Pharmacist Network intensive GPhc exam calculations
ANSWER 19
QUESTION 20
You work as a hospital pharmacist. Mr. Jay- 62-years who weighs 65kg is to receive an infusion of an antibiotic . He was prescribed 195mg of gentamicin to be given in 3 equally divided doses. The drug will be diluted in glucose 5% solution. Assuming the infusion will be given over the maximum time allowed , calculate the rate of infusion per dose in mcg/kg/min. Use the resource extract provided. Answer to 1.d.p.
ANSWER 20
QUESTION 21
A female patient needs to be treated with oral fluconazole capsules for Maintenance therapy to prevent relapse of cryptococcal meningitis. Given that the patient is 80-years-old and has a weight of 66kg and is 165cm tall with a serum creatinine is 280 micromol/L. Calculate creatinine clearance and state your answer as how many fluconazole 50mg capsules you would supply for 14 days treatment.
Male constant = 1.23 female = 1.04
See Link below
https://www.medicines.org.uk/emc/product/4437/smpc
London Pharmacist Network intensive GPhc exam calculations
ANSWER 21
QUESTION 22
London Pharmacist Network intensive GPhc exam calculations
ANSWER 22
QUESTION 23
A patient with a severe infection is prescribed meropenem at 1.25 g every 8 hours via IV infusion over 30 minutes. The available stock is 500 mg vials, which when reconstituted by adding sterile water to each vial. the final concentration after reconstituting a vial is 49mg/ml. You are aware that 500mg meropenem has a displacement volume of 0.1ml. Using the information provided, calculate the volume of sterile water that was added to reconstitute a 500mg meropenem vial.
ANSWER to 1 d.p.
UK’s most INTENSIVE GPhC exam calculations
ANSWER 23
49mg = 1ml
500mg = 10.204ml
Total volume – DV = volume added
10.204ml – 0.1ml = 10.1ml
ANSWER = 10.1ml
QUESTION 24
Mrs. F. a-43-year-old woman who has been experiencing very heavy, painful periods since the birth of her first child. Her GP has prescribed tranexamic acid 500 mg tablets. She presents in your chemist with her new prescription for use during her menstrual cycle whilst abroad for 2 months.
The SmPC for tranexamic acid 500 mg tablets is provided below.
The instructions on the prescription are to take 'as directed' and the patient cannot remember the maximum dosage her GP advised. What is the maximum recommended dosage of tranexamic acid that should be taken during her menstrual cycle whilst abroad for 2 months and state your answer as number of tablets you would supply to cover the treatment period whilst abroad.
UK’s most INTENSIVE GPhC exam calculations
ANSWER 24
From resource - 4g is maximum daily
8 tablets = 1 day
32 tablets = 4 days = 1 menstrual cycle
64 tablets = 2 menstrual cycles
ANSWER = 64 TABLETS
QUESTION 25
You require the following to make 250mg clobetasone ointment. Ingredients are listed below
1…….. Emulsifying ointment = 120mg
2…….. White soft paraffin = 30mg
3…….. Clobetasone butyrate = 62.5mg
4…….. Glycol stearate = 37.5mg
What is the concentration in % w/w of clobetasone in the ointment? Answer as a whole number
ANSWER 25
250
ANSWER = 25% w/w
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