Chapter 6: Calculations - APA's "The Pharmacy Technician"

False.

True.

True.

False.

Three.

1. Digits other than zero are significant.

2. Final zeros after a decimal points are always significant.

3. Zeros between two other significant digits are always significant.

4. Zeros used only to space the decimal are NOT significant.

Liquids:

1 L = 10 dL = 1000 mL

Liquids:

1 dL = 0.1 L = 100 mL

Liquids:

1 mL = .001 L = .01 dL

Solids:

1 kg = 1000 g

Solids:

1 g = .001 kg = 1000 mg

Solids:

1 mg = .001 g = 1000 mcg

Solids:

1 mcg = .001 mg = .000001 g

Avoirdupois:

1 lb = 16 oz

Avoirdupois:

1 oz = 437.5 gr

Apothecary:

1 gal = 4 qt

Apothecary:

1 qt = 2 pt

Apothecary:

1 pt = 16 fl oz

Apothecary:

1 fl oz = 8 fl dr (drams)

Apothecary:

1 fl dr = 60 min (minims)

Household:

1 tsp = 5 mL

Household:

1 tbsp = 3 tsp = 15 mL

Household:

1 cup = 8 fl oz

Temperature:

F= 1 4/5 x C + 32

Temperature:

9C = 5F - 160

Temperature:

C = 5/9 x (F - 32)

Common conversions:

1L = 33.8 fl oz

Common conversions:

1 pt = 473.167 mL

Common conversions:

1 fl oz = 29.57mL

Common conversions:

1 kg = 2.2 lb

Common conversions:

1 lb = 453.59 g

Common conversions:

1 oz = 28.35 g

Common conversions:

1 g = 15.43 gr

Common conversions:

1 gr = 64.8 mg

Equations and variables:

1 mL = 29.57 fl oz

x fl oz = (total prescribed mL) / (mL/fl oz conversion rate)

x fl oz = 120 mL / 29.57 mL

x = 4 fl oz

Equations and variables:

x (doses needed) = (capsules per dose) x (doses per day) x (# of days)

x= 1 x 3 x 7

x= 21

Equations and variables:

First: x KCI per mL = ?

20 mEq per 10 mL = 2 mEq per mL

Then:

x (mLs of KCI solution) = KCI needed / KCI per mL

x = (45 mEq) / (2 mEq)

x = 22.5

add 22. 5 mL of KCI solution to the IV bag

Mg per kg dose:

1. Convert lbs to kilograms (1 kg = 2.2 lbs)
2. Multiply the prescribed mg/kg by the child's weight in kg.

Formula for calculating children's doses (lb. based):

Weight of child/150 lbs x adult dose = child's dose

Body Surface Area formula for calculating children's doses:

Child's BSA x adult dose / avg. adult BSA = child's dose

Flow rate equation:

x mL/min or
x mL/hr = x mL/60 min
e.g. 80 mL/hr
= 80 mL/60 min
= 80/60
= 1.33 mL/min

Drops per minute equation:

x gtt/mL
x mL/hr = x mL/60 min

e.g. 30 gtt/min
80 mL/hr
= 80 mL/60 min x 30 gtt/1 mL (ratio)
= 2400 gtt/60 min
= 40 gtt/min

Milliequivalent equation:

Each electrolyte has a different mEq value based on atomic weight.

e.g. need 5 mEq of something that's in a 1.04 nEq/ml solution

how many mEq do you need?
x mL/5 mEq = 1 mL/1.04 mEq (ratio)
5/1.04
= 4.8 mL of solution is needed

Percent Solutions equation:

x volume wanted/ % wanted = x volume prescribed / % have (ratio)

then add all mL prescribed and subtract from total mL solution desired, what's left is the q.s.a.d.

It means there are 50 grams of Dextrose per 100 mL, totaling 500g of Dextrose in a 1000mL bag.

It means there are 25 grams of Dextrose per 100mL, totaling 250g of Dextrose in a 500mL bag.

(percent means grams 'per 100' in this case, 100 mL)

Determining concentration and converting a solution at one concentration to a solution having a different concentration.

Alligation method:

y = amount needed of weaker solution found by substracting the desired solution concentration from the concentration with the highest percentage. (95-70 = 25)

x= amount needed of the stronger solution by subtracting the weaker solution concentration from the desired solution concentration (70-50=20)

x/y ratio: 20/25

e.g. 20 parts 95% solution are needed for every 25 parts of 50% solution

*or* 4 parts 95% for every 5 parts 50%