Drug Calculations

Question 1

Convert 4.56 g to mg

Answer 1

4560 mg

Question 2

Change 75 mcg to mg

Answer 2

0.075 mg

Question 3

Convert 0.78 mg to mcg

Answer 3

780 mcg

Question 4

Change 950 mg to g

Answer 4

0.95 g

Question 5

A patient has been prescribed 40 mg. The stock tablets you have are 20 mg. How many tablets do you give the patient?

Answer 5

40/20 = 2 tablets

Question 6

A patient has been prescribed 0.06 mg. The stock tablets you have are 30 mcg. How many tablets do you give the patient?

Answer 6

0.06mg=60mcg 60/30 = 2 tablets

Question 7

What is the formula to calculate how many tablets to give?

Answer 7

Precription for the patient/stock strength available = tablets given

Question 8

What is the formula to calculate volumes for injection?

Answer 8

Prescription for the patients x stock volume(ml) / stock strength available = volume given

Question 9

A patient has been prescribed 2mg of Pethidine. The stock strength you have is 10mg/ml. How many ml do you give the patient?

Answer 9

2 x 1 / 10 = 0.2ml

Question 10

Thepatientneeds250mcgofDrugX.Youhave1mgin1ml.Howmanymldoyou give?

Answer 10

250 x 1 / 1000 = 25/100 = 0.25ml

Question 11

What is thr formula to workout the required dosage based on the weight of the patient?

Answer 11

Dosage required = prescription x body weight

Question 12

A patient has been prescribed Erythromycin, 40 mg/kg/dose. He weighs 74 kg. What is the dosage in mg?

Answer 12

40x74=2960mg

Question 13

Cloxacillin, 50 mg/kg/dose has been prescribed to a patient, whose weight is 45 kg.

a) How many mg are required for a single dose?
b) How many grams is this?

Answer 13

3a) 50x45=2250mg

3b) 2.25 g

Question 14

What is the formula to calculate infusion rate?

Answer 14

Volume required for the patient (ml) / time (hours)