Clinical Calculation 5th Edition

1
Clinical Calculation5th Edition

• Chapter 6
• Calculation of Oral Medications
• Pages 40 - 54

2
Oral Medications

• Medications that are administered by mouth and
  absorbed via the gastrointestinal tract are known
  as PO (by mouth or orally) drugs.
• Variation of the oral route is called sublingual
  (sL) route, whereby medication is placed under
  the tongue for absorption via the mucous
  membrane.
• Buccal route, medication is placed between cheek
  and gum for similar absorption.
• Neither sublingual nor buccal medications should
  be chewed or swallowed whole, as a rule they are
  not followed by water.
• Finally it is important to know different forms
  of oral medication and symbol used and understand
  how to read labels of medication containers, and
  calibrating on equipment used to dispense liquid
  medications.

3
Oral medication forms

• Tablets
• Contain a powered drug compressed into a tablet
• Coated tablets
• Covered with flavored coating to help swallowing
  and taste
• Enteric coated
• Delay dissolution till it reaches intestine, no
  dividing or crushed
• Capsules
• Gelatin container to conceal taste, ok to open
  and placed in the food
• Caplets
• Looks like capsules it may be coated, but it
  should not be broken
• Sustained-release capsules or tablets (time
  release)
• Coated to dissolve at different time, should not
  be broken.
• Liquids
• Dispensed as elixirs, syrups, suspensions or
  solutions

4
Pictures
5
The medicine cup

• Basically there are 3 different type of measuring
  cups that we deal with here, and they are
  collaborated in one or more of the 3 measuring
  systems
• Metric system
• Apothecaries system
• Household system

6
When solution is poured into a cup page 42

• Concave surface is called meniscus and reading
  should be done at its lowest point.
• Read the amount in a cup at the eye level and on
  the flat surface setting.
• Look and note the smallest collaboration amount
  in each cup. When measuring smaller amount use
  syringe for accuracy if not pre-measured. You
  may use syringe and/or administer with spoon.
• check and double check before administrating to
  make sure it is done correctly, it may require to
  be opened at the bedside for one more opportunity
  for correct dosage.
• If between factors use syringe to collaborate the
  correct amount.
• It measuring in teaspoon or tablespoon, round to
  nearest tenth

7
When administrating tablets

• Tablet is scored in half or quarter
• Use pill splitter to score un-scored pills
• If oral medications that are not to be broken/
  and it require ½ quantity, consult the pharmacist
  or the physician in regard to rounding

• Can be broken
• Tablets
• Contain a powered drug compressed into a tablet
• Capsules
• Gelatin container to conceal taste, ok to open
  and placed in the food

• Can not be broken
• Enteric coated
• Delay dissolution till it reaches intestine, no
  dividing or crushed
• Caplets
• Looks like capsules it may be coated, but it
  should not be broken
• Sustained-release capsules or tablets (time
  release)
• Coated to dissolve at different time, should not
  be broken.

8
Reading labels and calculating dosage

• Name of the drug and its generic name
• Dosage strength amount or concentration of the
  drug, per mL,
• Name of manufacturer
• Form liquid-mL, tablet,
• Expiration date
• Lot number- manufacturer's code in order to be
  able to track and trace incase of recall.
• Total amount per container.
• Direction for administration (or scoring),
  mixing, shaking
• Bar code
• Recommendation for storage (not on the list)
• Web site http//www.accessdata.fda.gov/scripts/cd
  er/drugsatfda/index.cfm?fuseactionReports.Reports
  Menu

9
The label for a bottle of medication is shown.

1. Identify the manufacturer's name.
2. Identify the dosage strength of the medication
3. Identify the generic name of the medication.
4. Identify the form of the medication.
5. Identify the trade name of the medication.

1. Pfizer
2. 20 mg
3. piroxicam

1. Capsules
2. Feldene

10
Order Lasix 20 mg PO
How many tablets should be administered?

• Starting factor ORDER
• Answer unit
• Equivalents equation
• Conversion equation

11
Order Aldactone 50 mg PO
How many tablets should be administered?

• Starting factor ORDER
• Answer unit
• Equivalents equation
• Conversion equation

1. Identify the manufacturer's name.
2. Identify the dosage strength of the medication
3. Identify the generic name of the medication.
4. Identify the form of the medication.
5. Identify the trade name of the medication.
6. Total amount in the container

12
Order Augmentin 500 mg PO
How many mL should be administered?

• Starting factor ORDER
• Answer unit
• Equivalents equation
• Conversion equation

13
Order Calan SR 240 mg PO
How many caplets should be administered?

1. Identify the manufacturer's name.
2. Identify the dosage strength of the medication
3. Identify the generic name of the medication.
4. Identify the form of the medication.
5. Identify the trade name of the medication.
6. Total amount in the container

• Starting factor ORDER
• Answer unit
• Equivalents equation
• Conversion equation

14
Order Brethine 5 mg PO
How many tablets should be administered?

1. Identify the manufacturer's name.
2. Identify the dosage strength of the medication
3. Identify the generic name of the medication.
4. Identify the form of the medication.
5. Identify the trade name of the medication.
6. Total amount in the container

15
Calculation based on body weight

• Prescription may prescribed according to a
  designated amount of drug per kilogram or pound.
• Because the amount of medication to be given is
  determined by the weight of the person, the
  weight and calculated dosage considered an
  equivalent relationship.
• Starting factor for this type of the problem is
  in pound or kilogram.
• Answer label is in whatever units the medication
  is dispensed (e.g., mL, mg, tab, etc.).

16
Use dimensional analysis to calculate the correct
amount to be administered per dose.

• Order Mintezol Suspension 25 mg per kg per dose
  PO for an adult weighing 60 kg
• Available Supply Mintezol Suspension
  (thiabendazole) 500 mg per 5 mL
• How many mL should be administered per dose?

• Starting factor weight
• Answer unit
• Equivalents equation
• Conversion equation

17
Use dimensional analysis to calculate the correct
amount to be administered per dose.

• Order Myambutol 15 mg per kg per dose orally for
  an adult weighing 118 lb
• Available Supply Myambutol (ethambutol) 400 mg
  per tab
• How many tablets should be administered per dose?

• Starting factor weight
• Answer unit
• Equivalents equation
• Conversion equation

18
A client who weighs 62 kg is to receive Nydrazid
5 mg per kg per day PO.  The drug label states
Nydrazid (isoniazid) 300 mg per tab. Use
dimensional analysis to calculate the correct
number of tablets to be administered per dose.

• Starting factor weight
• Answer unit
• Equivalents equation
• Conversion equation

19
Use dimensional analysis to calculate the correct
amount to be administered per dose.

• Order  Augmentin 20 mg per kg per day in divided
  doses PO every 8 hours for a client who weighs 38
  kg.

Remember to divide by the number of does per day.
20
Use dimensional analysis to calculate the correct
amount to be administered per dose.

• Order  Ancobon 50 mg per kg per day PO in
  divided doses every 6 hours for a client who
  weighs 176 lb
• Available Supply Ancobon (flucytosine) 500 mg
  per capsule 

g
n
Remember to divide by the number of does per day.
21
Clinical Calculation5th Edition

• Chapter 8
• Calculation of Parenteral Medications
• Pages 83 - 127

22
Parenteral Medication

• Medications that are administered via injection
  into dermal or intramuscular tissues or directly
  into vein are called parenteral medications.
• Administered by route outside the
  gastrointestinal tract.
• Parenteral route
• Intradermal (ID) -Chap 8
• Subcutaneous (subcut) -Chap 8
• Intramuscular (IM) -Chap 8
• Intravenous (IV) -Chap 10 and 11
• Intrathecal -not covered
• Intracardial -not covered
• Intra-articular -not covered

23
The Syringe and Needle

• Syringe
• Needle for penetration of the medication and the
  choice of needle depends on the route and site of
  administration, the size and obesity of the
  client, and viscosity of the medication.
• Hub lower end of the syringe and holds the
  needle.
• Barrel holds the medication
• Plunger made of clouded, color glass or plastic
  and it is operated to fill or empty the barrel
• Safety shield to protect its sterility for
  transport for injection and be locked into place
  to provide a permanent shield for disposal
  following injection, some syringes comes with
  retractable technologies which automatically
  retracts into the syringe barrel after injection.
  

Plunger
Barrel
Hub
Needle
24
The type of syringes

• The tuberculin syringes
• Measures a total of 1 mL, and it is calibrated in
  hundredths (0.01 mL) and also in minims (16
  minims per mL)
• Used for small quantities of medication and
  usually used with a 5/8 long needle
• The insulin Syringes
• Collaborated in Units and should be used only for
  administration of insulin. If very small
  quantity of medication ordered, it is also
  possible to use Tuberculin syringe, it requires
  conversion to mL or minims.
• It is available in 0.3 mL, 0.5 mL and 1 mL.
• The 0.5, 3, 6, 10, 12, and 35 mL Syringes
• Smaller ones are calibrated in 0.1 mL and larger
  ones 10, 12 are calibrated in 0.2 mL

25
The type of Needles

• The choice of needle depends on the route and
  site of administration, the size and obesity of
  the client, and viscosity of the medication.
• Varies in length from ¼ to 3.
• Shorter needles (1/4 1) are used for
  intradermal or subcutaneous injections
• Longer needles (1- 2) are used for
  intramuscular injections, irritating medications,
  and larger or obese clients.
• Diameter of the needle is indicated by a gauge
  number.
• Runs from 14 to 27, the larger the number , the
  smaller the diameter of the needle
• Fine needles are used for aqueous solutions and
  heavier needles for suspensions and oils.
• Bevel the angle point of the needle increases
  the sharpness of the needle
• See page 87 for pictures

26
Reading the Syringe

• On most single use syringes the plunger has a
  rubber tip that has 2 rings in contact with the
  barrel. Measurement must be made at the top
  ring, the one closer to the tip in order to read
  the accurate dose.

Read at this point and Not here
27
Read the following syringes
1.2 mL
6.4 mL
.38 mL
28
Rounding OFF

• Because clinical calculation does not round to
  nearest collaborate syringe size, it is necessary
  to round off these values.
• When calculating dose obtained does not results
  in tenths of milliliter, the carry your decimal
  to hundredths and then
• For 5 or more round up
• For less than 5 (4 or less) round down
• If using tuberculin syringe, it is possible to
  measure hundredths of mL. Therefore, the
  computation should be carried to thousandths and
  then round off to hundredths.

2.36 2.4 2.34 2.3
29
Parenteral Medication Forms

• Drugs for parenteral medication are available in
  a variety of forms. Some are powder or frozen
  form and it must be reconstituted to a liquid,
  where as others are in solution and are dispensed
  in
• Single Dose ampoules constricted stem that
  facilitates snapping them open
• Single- and Multiple-dose Vials the vial is
  entered through the rubber diaphragm
• Pre-filed Cartridges single-dose disposable
  cartridges, may or may not be a needle attached
  to the cartridge.

30
Reading Labels

• Manufacturers product insert describes, in
  detail, the composition of the drug, its action,
  indications and contraindications for use,
  precautions and adverse reactions, dosage,
  direction for dilution or reconstitution, and if
  necessary direction for administration.
• See sample on pages 93-94

31
Calculating dosages obtained from Premixed
Solutions

• Many parenteral drugs are dispensed in vials or
  ampoules that contain single or multiple doses.
• Label or printing on each container indicates the
  amount and the solution strength of the contents.
• Use this values as equivalent when calculating
  quality of solution is needed for the required
  dosage.

32
Read label

1. Identify the manufacturer's name.
2. Identify the dosage strength of the medication
3. Identify the generic name of the medication.
4. Identify the form of the medication.
5. Identify the trade name of the medication.
6. Total amount in the container

33
Read Label

1. Identify the manufacturer's name.
2. Identify the dosage strength of the medication
3. Identify the generic name of the medication.
4. Identify the form of the medication.
5. Identify the trade name of the medication.
6. Total amount in the container

34
Calculate the correct amount to be administered
per dose.
Order diazepam 2.5 mg IM

• Starting factor order
• Answer unit
• Equivalents equation
• Conversion equation

35

1. Identify the manufacturer's name.
2. Identify the dosage strength of the medication
3. Identify the generic name of the medication.
4. Identify the form of the medication.
5. Identify the trade name of the medication.
6. Total amount in the container
7. The medication should be stored below what
   temperature?

36
Calculate the correct amount to be administered
per dose.
Order Robinul 0.2 mg IM

• Starting factor order
• Answer unit
• Equivalents equation
• Conversion equation

37
A client is to receive chlorpromazine HCl 20 mg
IM.  The available supply is labeled Thorazine
(chlorpromazine HCl) 25 mg per mL.  How many
milliliters should the nurse withdraw for the IM
injection?

• Starting factor order
• Answer unit
• Equivalents equation
• Conversion equation

38
Prescription order states trimethobenzamide 0.2
g  IM.  The vial of medication is labeled
trimethobenzamide 100 mg per mL.  How many
milliliters should the nurse withdraw for the IM
injection?
39
Calculations based on Body Weight

• Method of calculating based on the body weight is
  similar to the method used in Parenteral dosages.
• You have to start from clients body weight.

40
Use dimensional analysis to calculate the correct
amount to be administered per dose.  Carry the
answer to the hundredths place and round to the
nearest tenth. 

• Order isoniazid 5 mg per kg per day IM for an
  adult weighing 45 kg (maximum 300 mg per day)
• Available Supply isoniazid 100 mg per mL

41
Use dimensional analysis to calculate the correct
amount to be administered per dose.  Carry the
answer to the hundredths place and round to the
nearest tenth. 

• Order Amikin 10 mg per kg as a loading dose for
  an adult weighing 125 lb
• Available Supply Amikin (amikacin) 250 mg per mL

42
Reconstitution of Drug in Powder Form

• Some drugs lose their potency a short time after
  being placed in solution, so they are not
  reconstituted until they are ready to be used.
• A sterile diluents, usually water or 0.9 sodium
  chloride (normal saltine) must be added according
  to directions on the label or manufacturers
  inserts.
• Label must indicate for injection or for
  injection. It is important that only diluents
  designed in the directions be used for
  reconstitution, because they have been determined
  to be compatible with the drug or the IV
  solutions to which the drug will be added.
• If asked for water do not added 0.9 sodium
  chloride.

43
Powder Form

• After the diluents is added, the vial must be
  shaken to dissolve the powder, then it may be
  drawn up into syringe for administration.
• Diluents volume
• May expand the volume of the solution.
• May not expand the volume of the solution.
• Read the drug label closely to make sure correct
  strength or concentration of the reconstituted
  solution to use for correct volume in your
  calculation.

44
Read label

1. Identify the manufacturer's name.
2. Identify the dosage strength of the medication
3. Identify the generic name of the medication.
4. Identify the form of the medication.
5. Identify the trade name of the medication.
6. Total amount in the container

45
Refer to the information on the medication
package provided. In addition to the IM
administration route, by which other route can
the medication shown be administered?
Intravenous
46
Units of Medication

• Some drugs are measured in quantities called
  units.
• It is frequently is used for hormones, vitamins,
  antibiotics,
• Because the type of effect varies for each drugs,
  there is no common definition for a units.

47
Read Label

1. Identify the manufacturer's name.
2. Identify the dosage strength of the medication
3. Identify the generic name of the medication.
4. Identify the form of the medication.
5. Identify the trade name of the medication.
6. Total amount in the container

48
Use dimensional analysis to calculate the correct
amount to be administered per dose.  Round to the
nearest tenth.  Calculate the number of mL to be
administered for the loading dose. Indicate this
amount on the syringe.
Order heparin sodium 3500 units subcut
49
Read label

1. Identify the manufacturer's name.
2. Identify the dosage strength of the medication
3. Identify the generic name of the medication.
4. Identify the form of the medication.
5. Identify the trade name of the medication.
6. Total amount in the container

50
Use dimensional analysis to calculate the correct
amount to be administered per dose.  Carry the
answer to the hundredths place and round to the
nearest tenth.  Calculate the number of mL to be
administered for the loading dose
Order Pfizerpen 3.2 million units in 4 divided
doses per day
51
Use dimensional analysis to calculate the correct
amount to be administered per dose.  Round to the
nearest tenth.  Calculate the number of mL to be
administered for the loading dose.
Order Pfizerpen  400,000 units IM
Available Supply reconstituted supply of Pfizerpen (penicillin G potassium) 500,000 units per mL
52
Clinical Calculation5th Edition

• Chapter 9
• Administration of Parenteral Medications
• Pages 138 - 142

53
Insulin Preparations

• Person with diabetes caused by insulin-secretion
  deficiency may be treated by one or more
  injection daily of manufactured insulin.
• Regular insulin is clear solution designated by
  letter R on the bottle. It is the only type of
  insulin that can be administered intravenously.
• Modified insulin designated by L (Lente Insulin),
  N (NPH insulin) and U (Ultralente insulin). They
  can only be administered subcutaneously.
• Lantus is a long acting synthetic human insulin
  administered subcutaneously.
• Combination of regular and modified insulin may
  have been ordered. Such combination may be
  reported as proportions of regular and modified.

54
Read Label
55
State the dosage strength of the insulin.
100 units per mL
56
Which of the following syringes should be used to
administer the order?  Answer using the name of
the correct syringe.
Order Humulin 50/50 insulin 18 units
subcutaneously
Unit-100