This document provides information on drug dosage calculation including objectives, types of medications, calculation methods, measurement systems, and terminology. It describes ratio and proportion, formula, and dimensional analysis methods. Measurement systems including metric, apothecary, and household are defined. Key terms like concentration, flow rate, and drop factor are explained. The document also covers titrating medications, oxytocin dosing recommendations, and barriers to accurate calculations.

1. DRUG DOSAGE CALCULATION
Dr MUSA MARENA

2. OBJECTIVES
• After completing this lecture, you should be able to:
• Describe the various types of oral medications.
• Apply ratio and proportion to solve oral drug dosage
problems.
• Apply the Formula Method to solve oral drug dosage
problems.
• Apply dimensional analysis to solve oral drug dosage
problems.
• Solve dosage calculation problems for medications in
similar and different measurement systems (use equivalent
values when necessary).
• Understand the rationales for critical thinking checks

3. WHY?
• Drugs are prescribed by their generic (official) name or trade (brand) names
and are packaged in an average unit dosage
• Tablets and capsules contain a solid concentration of drugs (paracetamol gr
x) whereas solution contain a specific amount of drug (usually gram weight)
dissolved in a specific amount of solution (usually mL’s or cc’s)
(promethazine 20mg per ml)
• Parenteral medications (IM, SC, IV) are package in vials, ampoules, and pre-
measured syringes. Dosages usually ranges from 1 to 3 ml
• Medication orders refer to drug dosages, so calculation will be necessary if
dosage prescribe is different from available dosage
• Some drugs are measured in units (heparin, insulin, penicillin), and others
are in solutions as mEq (grams per 1ml of solution). Some solutions need to
be reconstituted from a` powder form.
• Infants and children cannot receive the same dose of medication as adult
• Basic Math skills are needed to calculate most dosage and solution
problems encounter today in clinical practice
• Accurate dosage calculation are an essential component of total nursing
role in safe administration of medication

4. BARRIER TO DRUG CALCULATION
SUCCESS
Top ten reasons why healthcare professionals don’t think they need to maintain
competency in calculations:
 The computer does it
 The pharmacy does it
 The IV infusion pump does it
 We have charts and tables that do it
 The drug companies take care of it
 We use unit dose
 It’s just a nursing school exercise
 We have a unit-based pharmacist
 Math is just not one of my strengths
 It’s not a good use of my time
 It’s the responsibility of the doctor to explain what he meant (write the correct
amount)
Responsible professionals cannot afford to become complacent with drug
calculations as they are accountable for all drugs they administer

5. TERMS & TERMINOLOGY
• FLOW RATE: is the volume per unit time usually
expressed as ml/hr. can be ml/min or ml/sec
• DRIP RATE: is the number of drops per unit time usually
expressed as drops/min(dpm)
• DOSE: amount of drug per unit time given to the
patient expressed as mg/min, g/hr or IU/min
• CONCENTRATION: amount of the drug in a given
volume usually expressed as mg/ml, g/l or mIU/ml
• DROP FACTOR: is the number of drops per unit volume.
Expressed as drops/ml
• TITRATION: adjustment of the IV medication dosage
within prescribed parameters to achieve a desired
effects.

6. • NUMERATOR: the top portion of the fraction
• DENOMINATOR: the bottom portion of the fraction
• UNIT: a dimension that is given to a number. For
Example - If you are to give 50, you would ask, 50
what? This could be mg, mL, tablets, teaspoons, etc.
(mg, mL, tablets, tsp. are the units)
• UNIT EQUIVALENCIES: the value of equivalencies
between two units.
• For Example: 1 kg = 2.2lbs, 5mL = 1tsp, 30mL =
1ounce,
• CONVERSION FACTOR: it is a unit equivalency
written as a fraction.
1𝑘𝑔
2.2𝐼𝑏𝑠
𝑜𝑟
2.2𝐼𝑏𝑠
1𝑘𝑔
,
60𝑚𝑔
1𝑔𝑟𝑎𝑖𝑛
or
1𝑔𝑟𝑎𝑖𝑛
60𝑚𝑔

7. • DESIRED DOSE: the dose to be given, what you desire.
Also known as the GIVEN QUANTITY or DOCTOR’S
ORDER.
• WANTED QUANTITY: the answer (x); that is, mL, oz,
mg.
• AVAILABLE DOSE: the available amount of the drug,
what you have.
• UNIT PLACEMENT OR PATH AND CANCELLATION:
placement of the units of the fractions in the
numerator and the denominator positions so
cancellation can occur.
• COMPUTATION: the calculation process. Cancel first,
multiply the numerators, multiply the denominators,
and then divide the product of the numerators by the
product of the denominators.

8. MEASUREMENT SYSTEMS
• 3 main types
Apothecary
Household
Metric

9. VOLUME Metric Apothecary Household
4000ml 1gal(4qt)
1L (1000ml) 1qt (2pt)
500ml 1pt (16fl oz)
240ml 8 oz 1 glass/measuring cup
180ml 6oz 1 teacup
30ml 1 oz (8 dr) 2 tbsp
15ml ½ oz (4 dr) 1 tbsp (tablespoon)
5ml 1 dr (60M) 1 tsp (Teaspoon)
1ml 15 M 15 gtt
1 M(minim) 1 gtt(drop)
180mL 6 oz 1 teacup
WEIGHT 60-65 mg 1 gr -
1 g (1000mg) 15gr -
1kg (1000g) - 2.2 ib
1mg (1000mcg) - -
LENGTH 2.5cm - 1 inch

10. PREFIXES AND RELATIVE VALUES OF THE INTERNATIONAL SYSTEM (SI)
PREFIX MEANING
• Subdivisions
• atto- one quintillionth (1018) of the basic
unit
• femto- one quadrillionth (1015) of the
basic unit
• pico- one trillionth (1012) of the basic unit
• nano- one billionth (109) of the basic unit
• micro- one millionth (106) of the basic
unit
• milli- one thousandth (103) of the basic
unit
• centi- one hundredth (102) of the basic
unit
• deci- one tenth (101) of the basic unit
• Multiples
• deka- 10 times the basic unit
• hecto- 100 times (102) the basic unit
• kilo- 1000 times (103) the basic unit
• myria- 10,000 times (104) the basic
unit
• mega- 1 million times (106) the basic
unit
• giga- 1 billion times (109) the basic
unit
• tera- 1 trillion times (1012) the basic
unit
• peta- 1 quadrillion times (1015) the
basic unit
• exa- 1 quintillion times (1018) the
basic unit

11. CALCULATION METHODS
• Various methods are used for solving medication
calculation
• The most common methods are:
Formula,
Proportion
Dimensional Analysis
• No one method is best for solving every type of
problem. Several good approaches are available,
however and one of the best is dimensional analysis
• Rule #1 in drug calculations - STICK TO ONE
METHOD!

12. • REMEMBER: Drug calculation problems are simply story problems.
• You have to develop a mathematical problem from the information that is
provided.
• Reading comprehension is crucial in order to be successful at dosage
calculations. When reading the “story problem,” one must consider what
they have read and ask themselves several questions. These should include:
• What is being asked of me?
• What do I need to solve for?
• What units does my answer need to be expressed in?
• What units do I need in my problem and what units to I need to get rid of?
• Are there units in the problem that I need to convert in order to set up my
problem? (we always want to work with similar units whenever possible)
• What information in the problem do I need, and what information do I not
need?
• How do I set up my problem to leave only the desired units in the answer?
• Does my answer make sense? (very important)

13. FORMULA METHOD
• DOSE (D)=
𝐴𝑀𝑂𝑈𝑁𝑇 (𝐴)
𝑇𝐼𝑀𝐸 (𝑇)
• CONCENTRATION ( 𝐂) =
𝐴𝑀𝑂𝑈𝑁𝑇 (𝐴)
𝑉𝑂𝐿𝑈𝑀𝐸 (𝑉)
• FLOW RATE (𝐅𝐑) =
𝑉𝑂𝐿𝑈𝑀𝐸 (𝑉)
𝑇𝐼𝑀𝐸 (𝑇)
• FLOW RATE (𝐅𝐑) =
𝐷𝑂𝑆𝐸 (𝐷)
𝐶𝑂𝑁𝐶𝐸𝑁𝑇𝑅𝐴𝑇𝐼𝑂𝑁 (𝐶)
• DRIP RATE 𝐃𝐑 = 𝐹𝐿𝑂𝑊 𝑅𝐴𝑇𝐸 𝐹𝑅 × 𝐷𝑅𝑂𝑃 𝐹𝐴𝐶𝑇𝑂𝑅(𝐷𝐹)

14. PROPORTION METHOD
• Ratio is same as fraction
Use to express a relationship between two units or
quantities
A slash (/) or colon (:) is use to indicate division and both
are read as is to or per
With medication usually refers to weight of drug (i.e.
gram) in a quantity of the solution ( i.e. cc’s)
50mg/cc= 50mg of a drug (solute) in 1cc of a liquid
(solution)
• A proportion states that two ratios are equal
In fraction form where two fractions are equal 1/3=3/9
Colon form e.g. 1:3 :: 3:9

15. • A proportion consists of two ratios of equal value. The ratios are
connected by a double colon (::), which symbolizes the word as.
2 : 3 :: 4 : 6
• Read the above proportion: “Two is to three as four is to six.”
• The first and fourth terms of the proportion are the extremes. The
second and third terms are the means. 2 : 3 :: 4 : 6
• 2 and 6 are the extremes
• 3 and 4 are the means
• A helpful way to remember the correct location of the extremes
and means is
E = The end of the problem
M = The middle of the problem
• In a proportion the product of the means equals the product of
the extremes because the ratios are of equal value

16. DIMENSIONAL ANALYSIS
• Also known as factor analysis, factor-label
method, or unit-factor method, “chemistry
math”
• Dimensional Analysis relies on two simple
mathematical concepts.
Concept 1: When a nonzero quantity is divided
by the same amount, the result is 1.
Concept 2 When a quantity is multiplied by 1,
the quantity is unchanged.

17. • Given quantity: the beginning point of the problem,
commonly the doctor’s order.
• Wanted quantity: the answer to the problem
• Unit path: the series of conversions necessary to
achieve the answer to the problem
• Conversion factors: equivalents necessary to
convert between systems of measurement and to
allow unwanted units to be canceled from the
problem
• Each conversion factor is a ratio of units that equals
1.

18. METHODS
• Sequential
• random

19. Given quantity Conversion
factor for given
Quantity
Conversion
Factor For
Wanted
Quantity
Conversion
computation
Wanted
quantity

20. SEQUENTIAL METHOD
The problem-solving method of dimensional analysis uses the
following five steps.
• Identify the given quantity in the problem.
• Identify the wanted quantity in the problem.
• Establish the unit path from the given quantity to the wanted
quantity using unit equivalents as conversion factors.
• Set up the conversion factors to permit cancellation of unwanted
units. Carefully choose each conversion factor and ensure that it is
correctly placed in the numerator or denominator portion of the
problem to allow the unwanted units to be canceled from the
problem.
• Multiply the numerators, multiply the denominators, and divide
the product of the numerators by the product of the denominators
to provide the numerical value of the wanted quantity.

21. • Step 1. Identify the given quantity and its unit of measurement.
• Step 2. Identify the wanted unit of the answer.
• Step 3. Establish the unit path (to go from the given quantity and
unit to the arithmetic answer in the wanted unit), and identify the
conversion factors needed. This might include:
 (a) a conversion factor for the given quantity and unit, and/or
 (b) a conversion factor to arrive at the wanted unit of the answer.
• Step 4. Set up the ratios in the unit path such that cancellation of
units of measurement in the numerators and denominators will
retain only the desired unit of the answer.
• Step 5. Perform the computation by multiplying the numerators,
multiplying the denominators, and dividing the product of the
numerators by the product of the denominators.

22. RANDOM METHOD
• Similar to random sequential method
• The sequences of conversion factors is randomly
placed. The factors are placed without considering
which factor precedes its
• The units of the numerator portion correlates with
the numerator unit of the wanted quantity whilst
the denominators should correlates too.
• The unwanted units should cancel each other out

23. PERCENT & RATIO STRENGTH
• Percentage is Always a division of 100
• It means the “hundredth part”
• Has a symbol of %
• The concentrations of weak solutions are frequently
expressed in terms of ratio strength. Because all
percentages are a ratio of parts per hundred, ratio
strength is merely another way of expressing the
percentage strength of solutions or liquid
preparations (and, less frequently, of mixtures of
solids).

24. For example, 5% means 5 parts per 100 or
5:100.
Although 5 parts per 100 designates a ratio
strength, it is customary to translate this
designation into a ratio, the first figure of which
is 1; thus, 5:100 = 1:20.

25. • The concentrations of weak solutions are frequently expressed in terms of ratio
strength. Because all percentages are a ratio of parts per hundred, ratio strength is
merely another way of expressing the percentage strength of solutions or liquid
preparations (and, less frequently, of mixtures of solids). For example, 5% means 5
parts per 100 or 5:100. Although 5 parts per 100 designates a ratio strength, it is
customary to translate this designation into a ratio, the first figure of which is 1;
thus, 5:100 = 1:20.
• When a ratio strength, for example, 1:1000, is used to designate a concentration, it is
to be interpreted as follows:
• For solids in liquids=1 g of solute or constituent in 1000 mL of solution or liquid
preparation.
• For liquids in liquids = 1 mL of constituent in 1000 mL of solution or liquid
preparation.
• For solids in solids = 1 g of constituent in 1000 g of mixture.
• The ratio and percentage strengths of any solution or mixture of solids are
proportional, and either is easily converted to the other by the use of proportion.
• Some medications like epinephrine are written as 1 in1000, 1in 10000, 1 in 100000
or as 1:1000, 1:10000, 1:100000.
• This means 1g of solute in 1000ml of solution, 1g in 10000ml, 1in 100000ml, 1g in
1000000ml or 1g:1000ml

26. TITRATING MEDICATIONS
• Titration is adjustment of the dose, either
increasing or decreasing, to attain the desired
patient response.
• Weaning is a gradual decrease of the dose
when the medication is being discontinued

27. OXYTOCIN RECOMMENDATION
• Low dose 0.5-3mIU/min
 Mainly use for induction of labour
 Practical purpose starting dose: 2.5mIU/min increasing every 20-30min interval.
 Adequate contraction may be establish at 12-16mIU/min
 Maximum licensed dose is 20mIU/min
• High dose 4-6mIU/min
 Augmentation or active management of labour
 Practical purpose starting dose: 5mIU/min increasing every 20-30min interval
 Maximum licensed dose is 20mIU if higher dose is required should not be more than 32mIU/min.
 Note for nulliparous maximum dose can be as high as 60mIU/min
• For ease of calculation multiples of 5 are taken as the starting dose. Ie 2.5mIU/min for low
dose and 5mIU/min for high dose.
• Standard concentrations prepared are 5mIU/ml, 10mIU/ml or 20mIU/ml corresponding
to2.5IU, 5IU and 10IU in 500mls of fluid respectively
• Preparation of oxytocin
• Oxytocin is administered via an infusion pump to allow precise control of the rate of
administration
• Oxytocin is diluted by mixing 30 units in 500 mL to allow an infusion pump setting that
matches dose administration, i.e., 1 mIU per minute equals 1 mL per hour.
• Oxytocin is given IV and reaches a steady state in plasma in about 30-40 minutes. The
therapeutic response to a certain dose of oxytocin is unpredictable, although most patients
enter labor and go on to delivery with doses of 11-13 mIU per minute.

28. OXYTOCIN PROTOCOL
• Example of low-dose protocol:
• Initial dose of oxytocin..................................0.5 to 3 mU/min
• Increase interval......................................................30 minutes
• Dosage increment....................................................1 to 2 mU
• Usual dose for good labour.........................8 to 12 mU/min
• Maximum dose before reassessment.................30 mU/min
• Example of high-dose protocol:
• Initial dose of oxytocin..................................4 to 6 mU/min
• Increase interval............................................15 to 30 minutes
• Dosage increment...........................................4 to 6 mU/min
• Usual dose for good labour.........................8 to 12 mU/min
• Maximum dose before reassessment.................30 mU/min

29. Induction: High vs Low Dose protocols
Regimen Starting dose
mU/min
Incresae
mU/min
Interval
min
Usual Dose
for good
labour
mU/min
Maximum
recommended
dose mU/min
Low dose 0.5-3 0.5-3 30-60 8-12 30
High dose 4-6 4-6 15-30 8-12 30

30. BNF
• Induction-------: 0.001-0.004unit/min (1-4mIU/min)
• Adequate contraction usually 0.01unit/min
(10mIU/min)
• Max license --------------------------------- 0.02unit/min
(20mIU/min)
• Incomplete abortion------- 0.02-0.04unit/min (20-
40mIU/min)

31. SAFE DOSE
• Doses recommended for a given drug so as to
avoid toxicity.
• Its is the therapeutic range of the drug
• Found compile in documents
• British national drug formula (BNF)
• Normally based on
Amount per unit time
Amount per body weight
Amount per body surface area

32. BODY SURFACE AREA
• Use either a normogram chart to fine the
body surface area or
• Body surface area BSA=√
𝑤𝑒𝑖𝑔ℎ𝑡 𝑘𝑔 ×ℎ𝑒𝑖𝑔ℎ𝑡(𝑐𝑚)
3600

33. • Remember, in any drug calculation, if you do not
include the proper unit in your answer, your answer
will be WRONG!
• Example: 5 mL, not 5………2 tsp, not 2………1 tablet,
not 1

34. PAEDIATRICS DRUG CALCULATION
• Posology ( Greek póso(s) how much + -logy)
the branch of medicine concerned with the determination of appropriate doses of
drugs or agents [ from French posologie, from Greek posos how much]
1. Proportion to age
A. Young’s formula
𝑑𝑜𝑠𝑒 𝑓𝑜𝑟 𝑎 𝑐ℎ𝑖𝑙𝑑 =
𝑎𝑔𝑒 (𝑦𝑒𝑎𝑟𝑠)
𝑎𝑔𝑒 + 12
× 𝑎𝑑𝑢𝑙𝑡 𝑑𝑜𝑠𝑒
The above formula is used for calculating the doses for children less than 12years of
age (1-12years)
A. Dilling’s formula
𝑑𝑜𝑠𝑒 𝑜𝑓 𝑎 𝑐ℎ𝑖𝑙𝑑 =
𝑎𝑔𝑒(𝑦𝑒𝑎𝑟𝑠)
20
× 𝑎𝑑𝑢𝑙𝑡 𝑑𝑜𝑠𝑒
The above formula is used for calculating the doses of a child in between 4-20years of
age
A. Fried’s formula
𝑑𝑜𝑠𝑒 𝑓𝑜𝑟 𝑎 𝑐ℎ𝑖𝑙𝑑 =
𝑎𝑔𝑒 𝑖𝑛 𝑚𝑜𝑛𝑡ℎ𝑠
150
× 𝑎𝑑𝑢𝑙𝑡 𝑑𝑜𝑠𝑒

35. 1. Calculation base on body surface area
A. Catzel rule:
𝐷𝑜𝑠𝑒 𝑓𝑜𝑟 𝑡ℎ𝑒 𝑐ℎ𝑖𝑙𝑑 =
𝑠𝑢𝑟𝑓𝑎𝑐𝑒 𝑎𝑟𝑒𝑎 𝑜𝑓 𝑐ℎ𝑖𝑙𝑑
𝑠𝑢𝑟𝑓𝑎𝑐𝑒 𝑎𝑟𝑒𝑎 𝑜𝑓 𝑎𝑑𝑢𝑙𝑡
× 𝑎𝑑𝑢𝑙𝑡 𝑑𝑜𝑠𝑒
The average body surface area for an adult=1.73m2
Hence
𝐷𝑜𝑠𝑒 𝑓𝑜𝑟 𝑡ℎ𝑒 𝑐ℎ𝑖𝑙𝑑 =
𝑠𝑢𝑟𝑓𝑎𝑐𝑒 𝑎𝑟𝑒𝑎 𝑜𝑓 𝑐ℎ𝑖𝑙𝑑
1.73𝑚2
× 𝑎𝑑𝑢𝑙𝑡 𝑑𝑜𝑠𝑒
1. Calculation base on body weight:
A. Clark’s rule
𝐷𝑜𝑠𝑒 =
𝑤𝑡 𝑖𝑛 𝑙𝑏
150𝑙𝑏
× 𝑎𝑑𝑢𝑙𝑡 𝑑𝑜𝑠𝑒(𝑚𝑔)
𝐷𝑜𝑠𝑒 =
𝑤𝑡 𝑖𝑛 𝑘𝑔
70𝑘𝑔
× 𝑎𝑑𝑢𝑙𝑡 𝑑𝑜𝑠𝑒(𝑚𝑔)
The rule is applicable only when child dose is less than 150lb or 70kg

36. Temperature Conversions
• Medication orders often use Centigrade temperature.
• The relationship of centigrade © and Fahrenheit (F)
degrees is
 90 𝐶 = 50 𝐹 − 1600
• To convert from Fahrenheit to Centigrade, use this formula:
 °C = (°F − 32) ÷ 1.8
 °C = (°F − 32) ÷
9
5
• To convert from Centigrade to Fahrenheit, use this formula:
 °F = (°C × 1.8) + 32
 °F = (°C ×
9
5
) + 32

37. Here is a table of approximate
temperature equivalents:
fahrenheit centigrade
212 100
105 40.56
104 40
103 39.44
102 38.89
101 38.33
100 37.78
99 37.22
98.6 37
97 36.11
96 35.56
32 0

38. FLUID THERAPY
• In fluid therapy maintenance is calculated using 4, 2, 1 formula (Holliday-
Segar’s Formula): This was standard looking at maintenance daily fluid
requirement of health children
 4ml/kg/hr. for first 10kg,
 2ml/kg/hr. for next 10kg
 1ml/kg/hr. for remaining kilogram weight.
• This can be simplified by using formula
• Maintenance fluid requirement (ml/hr) = {60+ (Weight kg-20)} ml/hr for
weight ≥20kg
• Example: 65kg women who is nil per Os will require
 Fluid required= 60+ (65-20)
 60+45
 105ml/hr of intravenous infusion
• Similarly 70kg who had fasted over (night) 8hrs for elective surgery will have
deficit of
 Fluid deficit = 60 + (70-20)
 =60 + 50ml
 =110ml/hr
 Hence total fluid deficit is 110ml/hr ×8hr=880ml

39. SAMPLE QUESTION
• A woman is admitted to the labor room with a diagnosis of preterm labor. She states that she has not seen a
physician because this is her third baby and she “knows what to do while she is pregnant.” Her initial workup
indicates a gestational age of 32 weeks, and she tests positive for Chlamydia and Strep-B. Her vital signs are: T
100° F; P 98; R 18; B/P 140/88mmHg; and the fetal heart rate is 140–150. The orders include the following:
• NPO
• IV fluids: D5/RL 1,000 mL q8h
• Electronic fetal monitoring
• Vital signs q4h
• Dexamethasone 6 mg IM q12h for 2 doses
• Brethine (terbutaline sulfate) 0.25 mg subcutaneous q30 minutes for 2h
• Rocephin (ceftriaxone sodium) 250 mg IM stat
• Penicillin G 5 million units IVPB stat; then 2.5 million units q4h
• Zithromax (azithromycin) 500 mg IVPB stat and daily for 2 days
1. Calculate the rate of flow for the D5/RL in mL/h.
2. The label on the dexamethasone reads 8 mg/mL. How many milliliters will you administer?
3. The label on the terbutaline reads 1 mg/ml. How many milliliters will you administer?
4. The label on the ceftriaxone states to reconstitute the 1 g vial with 2.1 mL of sterile water for injection, which
results in a strength of 350 mg/mL. How many milliliters will you administer?
5. The instructions state to reconstitute the penicillin G (use the minimum amount of diluent), add to 100 mL
D5W, and infuse in one hour. The drop factor is 10drops/ml. What is the rate of flow in gtts/min? The label on
Penicillin G reads pfizerpen (penicillin G Potassium) for injection 5million units. Additional information
18.2ml diluent added gives 250 000units/ml, 8.2ml diluent added gives 500 000units/ml and 3.2ml diluent
added gives 1 000 000units/ml of solution.
6. The instructions for the azithromycin state to reconstitute the 500 mg vial with 4.8 mL until dissolved, and
add to 250 mL of D5W and administer over at least 60 minutes. What rate will you set the infusion pump if
you choose to administer the medication over 90 minutes? If drop factor is 15drops/ml, what is the drip rate?

40. The patient continues to have uterine contractions, and a new order has been written:
 Magnesium sulfate 4g IV bolus over 20 minutes, then 1g/h.
 The label on the vial of magnesium sulphate is 50% w/v and IV bag states magnesium
sulfate 40 g in 1,000 ml.
1. What is the rate of flow in mL/h for the bolus dose? If the drop factor is 20gtt/mL,
determine the drip rate?
2. What is the rate of flow in mL/h for the maintenance dose? If the drop factor is 60gtt/min,
determine the flow rate in gtt/min?
3. What volume of magnesium sulphate was withdrawn for the bolus and how many
mililitres of magnesium sulphate was place in the IV bag?
The patient continues to have contractions and her membranes rupture. The following orders
are written:
 Discontinue the magnesium sulfate.
 Pitocin (oxytocin) 10 units/1,000 mL RL, start at 0.5mIU/min increases by 1 mU/min q20
minutes.
 Stadol (butorphanol tartrate) 1mg IVP stat.
1. What is the rate of flow in mL/h for the initial dose of Pitocin? The drop factor is
60mcgtt/mL. Calculate the flow rate in mcgtt/min.
2. The Pitocin is infusing at 9 mL/h. How many mU/h is the patient receiving? Find the drip
rate if the drop factor is 10gtt/mL?
3. What would be the drip rate after 1hr of initiating Pitocin using drop factor of 15.
4. The vial of butorphanol tartrate is labeled 2 mg/mL. How many milliliters will you
administer?

41. Postpartum the woman developed postpartum haemorrhage. The following orders are written
 Massage uterus for contraction q15min, continuous monitoring vitals.
 Pitocin 20unit in 500ml NS, giving at 20miU/min
 Ergometrin 1mg IM stats
 Tablets Misoprostol 800mcg PR stats
 Transfuse 2units of whole blood over 6hours.
1. what is the flow rate of the Pitocin drip? Using IV set of 20drops/ml at what drip rate would the nurse regular
the drip?
2. Label on the Ergometrin ampoule 0.5mg/ml. how many millileters will the nurse administer?
3. Misoprostol packet label 200mg/tablets. How many tablets should be inserted PR?
4. A unit of blood has 400ml. if the blood giving set gives 15drops/ml what rate should the flow rate hence
calculate the drip rate be regulated
3 days later patient develop fever chill rigors foul smelly vaginal discharge and uterine tenderness. Diagnosis of
puerperal sepsis was made and the following order are written
 Tablets paracetamol 1g every 6hours
 IV Clindamycin 900mg every 8hours
 IV Gentamycin 1.5mg/kg every 8hours
 IV 500mlof NS over 30minutes then maintenance of 3liters over the next 24hrs
1. Sachet of paracetamol has 250mg/tablet. How many tablets should the patient receive?
2. Label on the clindamycin vial is 150mg/ml. how many milliters should the patient receive each dose?
3. Gentamycin vial label 20mg/ml. the patient weighs 65kg. How many milligrams is the patient supposed to
receive hence how many milliliter of gentamycin should be given to the patient for each dose?
4. If the drop factor of the set is 15drops/ml. what is the flow rate for the maintenance. What should be the
drip rate? If the patient weighs 75kg what should be appropriate maintenance fluid requirement?
5. Patient was discharge two weeks after admission.

42. 1.The physician has ordered 1000mL D5W with 5units oxytocin intravenously. Begin at
1mU/min and then increase by 1mU/min every 30 minutes until regular contractions
occur. The maximum dose is 20mU/min.
Calculate the IV flow rate (mL/hr.) for the beginning infusion.
Calculate the IV drip rate for the beginning infusion.
Calculate the maximum IV flow rate the Pitocin infusion may be set for.
Calculate the maximum IV drip rate the Pitocin infusion may be set for
2. The physician has ordered 1000mL D5W with 10units oxytocin intravenously. Begin
at 5mU/min and then increase by 5mU/min every 30minutes until active labor is
achieved. Maximum dose is 30mU/min.
Calculate the IV flow rate (ml/hr) for the beginning infusion
Calculate the IV drip rate for the beginning infusion.
Calculate the maximum IV flow rate (mL/h) for the beginning infusion.
What is the maximum IV drip rate the Pitocin infusion may be set for?
3. The physician has ordered 500mL D5W with 10units oxytocin intravenously. Begin
at 5mU/min and then increase by 5mU/min every 30minutes until regular contractions
occur. The maximum dose is 60mU/min.
a. Calculate the IV flow rate (mL/h) for the beginning infusion.
b. Calculate the IV drip rate for the beginning infusion.
c. Calculate the maximum IV flow rate the Pitocin infusion may be set for.
d. Calculate the maximum IV drip rate the Pitocin infusion may be set for.

43. 4. The physician has ordered 1000mL lactated Ringer’s with 20g magnesium sulfate.
You are to administer a bolus with 4g/30min, then maintain a continuous infusion at
2g/hr.
Calculate the IV rate (mL/hr) for the bolus order.
Calculate the IV drip rate for the bolus order.
Calculate the IV rate (mL/hr) for the continuous infusion.
Calculate the IV drip rate for the continuous infusion.
5: The physician has ordered 500mL lactated Ringer’s with 10g magnesium sulfate. You
are to administer a bolus with 2g/20min, then maintain a continuous infusion at 1g/hr.
a. Calculate the IV rate (mL/hr) for the bolus order.
b. Calculate the IV drip rate for the bolus order.
c. Calculate the IV rate (mL/hr) for the continuous infusion.
d. Calculate the IV drip rate for the continuous infusion
6: The physician has ordered 1000mL lactated Ringer’s with 10g magnesium sulfate.
You are to administer a bolus with 2g/30min, then maintain a continuous infusion at
2g/hr.
a. Calculate the IV rate (mL/hr.) for the bolus order.
b. Calculate the IV drip rate for the bolus order.
c. Calculate the IV rate (mL/hr) for the continuous infusion.
d. Calculate the IV drip rate for the continuous infusion.

44. Oxytocin ordering
• IV oxytocin (pitocin) 10units infuse at 20mU/min
• 1000ml D5W with 10units oxytocin intravenously.
Begin at 1mU/min and then increase by 1mU/min
every 30min until regular contractions occur. The
maximum dose is 20mU/min.

45. • In obstetrics, a pitocin (oxytocin) drip can initiate
labour. The standard solution is 15units in 250ml
(60mIU/ml). Because 1unit=1000miliunits.
• Order Pitocin (oxytocin) drip 2miliunits/minutes
IV. Supply: infusion pump, standard solution
15units in NS 250ml.
• Pitocin (oxytocin) 2miliunits/minutes IV. Supply
infusion pump, solution of 9units in 150ml NS
(60mIU/ml).

46. THANK YOU