Script Notes and Prescribing Practices Flashcards
1kg = 1000g
1g = 1000 milligrams (mg)
1mg = 1000 micrograms (mcg)
1mcg = 1000 nanograms (ng)
Americans use decilitres (dl)
dl = millilitres
This is % weight (w) by weight)
- % weight by weight (w/w)
- a weight of medicine is added to the weight of a diluent
- 1% w/w contains 1g of medicine in 100g
How much medicine would there be in a 0.5% w/w in a 100g?
1 - 1g
2 - 0.5g
3 - 1.5g
4 - 2g
2 - 0.5g
- 0.5% w/w = 0.5g /100g
How much medicine is present in sodium chloride at 0.9% w/w in 100ml in milligrams (mg)?
1 - 900
2 - 90
3 - 9
4 - 9000
1 - 900
- 0.9g in 100ml
- 0.9g/100ml = 900mg/100ml
- 900mg/100ml = 9mg/ml
This is % weight (w) per volume (v)
- % w/v
- a weight of medicine is added to the volume of a diluent
- 1% w/v contains 1g of medicine in 100ml
How much medicine would there be in a 0.9% w/v in a 100ml?
1 - 90mg
2 - 9g
3 - 0.9g
4 - 9000mg
3 - 0.9g
- 0.9% w/v = 0.9g/100ml
- same as 900mg/100ml
- same as 9mg/ml
This is % weight (v) per volume (v)
- % v/v
- a volume of medicine is added to the volume of a diluent
- 1% v/v contains 1ml of medicine in 100ml
How much medicine would there be in a 70% v/v in a 100ml?
1 - 7ml
2 - 70ml
3 - 70g
4 - 700ml
2 - 70ml
- 70% v/v = 70ml/100ml
- 0.7ml/100ml
A 500ml solution has a 5% glucose. How much glucose is in the 500ml?
1 - 50g
2 - 500ml
3 - 5g
4 - 25g
4 - 25g
- 5% of 500 = 25
- 5% w/v = 25 g of glucose
- same as 5g/100ml
A lidocaine solution has a 0.5% w/v in a 10ml injection. How much lidocaine is in the solution?
1 - 500mg
2 - 0.05g
3 - 0.5g
4 - 5000mg
2 - 0.05g
- 10ml x 0.005 = 0.05g
this is basically half a %
OR - 10ml x 0.01 = 0.1
0.1 / 2 = 0.05g - 0.05g = 50mg
A sodium bicarbonate solution has a 8.4% w/v in a 100ml infusion. How much sodium bicarbonate is in the solution?
1 - 8.4g
2 - 84,000mg
3 - 84g
4 - 8.4mg
1 - 8.4g
- 100 / 0.084 = 8.4g
- 8.4g = 840mg
Ratio calculations
1:1000 of adrenaline
= 1g adrenaline in 1000ml
= 1000mg / 1000ml
= 1mg/1ml
Ratio calculations
1:200,000 of adrenaline
= 1g adrenaline in 200,000ml
= 1000mg / 200,000ml
(divide both sides by 1000)
= 1mg/200ml
divide both sides by 200
= 5 micrograms/1ml
Weight conversions:
1 stone = 14 pound (lbs)
1lb = 450g
1 stone = 6.35kg
Height conversions:
1 foot = 12 inches
1 inch = 25.4 millimetres
1 foot = 304.8 millimetres
Patient weights 13.4 stone. What is the closest to their weight in metrics?
1 - 95kg
2 - 70kg
3 - 84kg
4 - 105kg
3 - 84kg
- 1 stone = 6.35kg
6.35 x 13 = 82.55kg - 1lb = 450g
(4 x 450)/1000 = 1.8kg - 1.8 + 82.55 = 84.35kg
Patient weights 7 stones and 8 lbs. What is the closest to their weight in metrics?
1 - 48kg
2 - 44kg
3 - 50kg
4 - 52kg
1 - 48kg
- 14lbs in 1 stone
(14 x 7) + 8 = 106lbs - 1lbs = 450g
(106 x 450) /1000 = 47.7kg
divide by 1000 as the number
is initially in g and we need kg
A patient is 5 foot and 5 inches tall. Convert this to metres?
1 - 1.70m
2 - 1.60m
3 - 1.65m
4 - 1.55m
3 - 1.65m
- 1 foot = 12 inches
(5 x 12) + 5 = 65 inches - 25.4mm in 1 inch
25.4 x 65 = 1651mm - 1m = 1000mm
1651 / 1000 = 1/651m
When prescribing gentamicin, we base the dose on which of the following:
1 - actual body weight
2 - ideal body weight
3 - body surface area
2 - ideal body weight
- avoids excessive dose in obese patients
If a patient weighs 100kg, with an ideal body weight of 54.5kg, and a body surface area of 1.49m2. What dosage should she be given if the standard dose is 5mg/kg?
1 - 55mg
2 - 100mg
3 - 280mg
4 - 500mg
3 - 280mg
- we need to use ideal body weight
- 5 x 54.5 = 272.5mg
Vancomycin needs to be diluted to 5mg/ml and run at a rate no faster than 10mg/min.
- 1st
1000mg in 1000ml = 1mg/ml
2nd
- 1000ml / 5 =200ml
1000mg / 5 = 5mg/200ml
So if you have a solution of 1000mg (or 1g) and we need to run it at no more than 10mg/min:
- 1000mg / 10 = 100 minutes
We then need to known how much is in a standard 250ml bag:
- in a 250ml bag = 4mg / 1ml
- so we need: 10 / 4 = 2.5
so in 2.5ml we have 10mg - so we can run the solution at 2.5ml/min, or 150ml/hour