© 2012 The McGraw-Hill Companies, Inc. All rights reserved. Chapter 14 Parenteral Dosages and Other Medication Administration Forms PowerPoint ® Presentation

© 2012 The McGraw-Hill Companies, Inc. All rights reserved.

Chapter 14 Parenteral Dosages and Other Medication Administration Forms

PowerPoint® Presentation to accompany:

Math and Dosage Calculations for Healthcare ProfessionalsFourth Edition

Booth, Whaley, Sienkiewicz, and Palmunen

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14.1 Calculate doses of parenteral medication in solution and select a syringe based on the dosage calculation.

14.2 Calculate doses of medication expressed in percent or ratio format.

Learning Outcomes

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14.3 Calculate doses of reconstituted parenteral medications.

14.4 Differentiate other medication administration forms and equipment.

Learning Outcomes

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Key Terms Absorption rate

Inhalant

Instillations

Metered dose Inhalers (MDIs)

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Introduction

Parenteral medications Bypass the digestive tract

Include Injections Inhalants Rectal drugs Transdermal drugs

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Introduction (cont.)

Injection types & absorption rates

Intravenous (IV) – 30 to 60 seconds

Intramuscular (IM) – 10 minutes or more

Subcutaneous (Subcut) – 15 minutes or more

Intradermal (ID) – sustained rate

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Calculating Parenteral Dosages in Solution Injections

mixtures that contain the drug dissolved in an appropriate liquid

Dosage or solution strength the amount of drug contained within a

volume of solution

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Calculating Parenteral Dosages In Solution (cont.) Dosage strength expressed

in milligrams per milliliter

as a percent

Lidocaine 1% = 1 g lidocaine /100 mL

as a ratio

Epinepherine 1:1000 = 1 g epinepherine / 1000 mL

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Calculating Parenteral Dosages In Solution (cont.)

Physician’s order – the amount of medication

Calculate – milliliters of solution that contains the desired dose

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Follow the ABCs of dosage calculation.

Start with H, Q, and D

Step A: Convert

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Step B: Calculate Proportion Dimensional Analysis Formula Method

Step C: Think!...Is It Reasonable?

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Syringe Sizes

After you determine the amount to give,

you must select the appropriate syringe

and needle.

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Syringe Sizes (cont.)

RRuleule 14-1 14-1 Selecting a syringe:

1. If the amount of injection to administer is 1 mL or more, use a standard 3 mL syringe.

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Syringe Sizes (cont.)

RRuleule 14-1 14-1 (cont.)

2. If the amount of injection to administer is less than 1 mL, use a 1-mL tuberculin syringe.

3. If the amount of injection to administer is less than 0.5 mL, use a 0.5-mL tuberculin syringe.

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Calculating Parenteral Dosages in Solution (cont.)

Amount to be administered is calculated at 0.6 mL. Which

syringe would you use?

Since this is less than 1 mL and greater than 0.5 mL, a tuberculin syringe should be used.

Example Example

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Rule 14-2 Rule 14-2 Rounding the Amount to Administer:

1. Round volumes greater than 1 mL to the nearest tenth (one decimal).

2. Round volumes less than 1 mL to the nearest hundredth (two decimals).

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Amount to be administered is calculated to be 1.66 mL

The volume is greater than 1 mL – round to the nearest tenth – 1.7 mL

ExampleExample

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Amount to be administered is calculated to be0.532 mL.

The volume is less than 1 mL – round to the nearest hundredth – 0.53 mL.

Example Example

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Can the amount to be administered be safely injected into one site?

If not, divide the amount into equal (or nearly equal) parts.

Administer them in separate sites.

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Rule 14-3 Rule 14-3 Maximum volumes for injections:

Intramuscular Injections Adult 3 mL Adult Deltoid (arm) 1 mL Child (6-12 years old) 2 mL Child (0-5 years old) 1 mL Infant (premature) 0.5 mL

Subcutaneous injections 1 mL

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Ordered: Compazine 7.5 mg IM

On hand: Compazine 5 mg/mL

Find the amount to administer and select the proper

syringe.

Example Example

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H = 5 mg

Q = 1 mL

D = 7.5 mg

Step A No conversion is needed.

Example (cont.) Example (cont.)

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Step B Use method of choice to calculate

amount to administer.

7.5 mg / 5 mg x 1 mL = A

1.5 x 1 mL = 1.5 mL = A


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Step C Desired dose is 1.5 times the dose on hand, so it is reasonable.

Standard 3 cc syringe is used since amount to administer is greater than 1 cc.


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Medications Expressed in Percent or Ratio Format

Medications labeled as percents or ratios must be converted before calculating amount to administer.

Percent (per 100) means grams per 100 mL.

Ratio means gram per mL.

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Rule 14-4Rule 14-4 When a solution strength is expressed as a percent or ratio:

1. Convert the percent or ratio to a dosage strength of g/mL, mg/mL, or units/mL.

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Rule 14-4Rule 14-4 (cont.)

2. Calculate the amount to administer; then apply Rules 14-1 to 14-3.

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Medications Expressed in Percent or Ratio Format (cont.)

Find the amount to administer and select the proper syringe.

Ordered: magnesium sulfate 300 mg IM

On hand: magnesium sulfate 10% solution

Patient: 75 pound 8 year-old female

Example Example

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H = 10 g Q = 100 mL D = 300 mgStep A Convert

10 % solution = 10 g (H) / 100 mL (Q)

D : 300 mg = 1 g : 1000 mg

300 x 1 g = D X 1000

300 g/1000= 0.3 g = D


0.3 g

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Step B Calculate using method of choice.

0.3 g / 10 g x 100 mL = A

0.03 x 100 mL = A

3 mL = A

Example (cont.)Example (cont.)

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Step C The concentration of the medication is 1 to 10, so the volume to be administered should be 10 times the desired dose.

3 is 10 times larger than 0.3, so it is reasonable.


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The amount to administer is 3 cc, so a standard 3 cc syringe can be used.

However, because the patient is 8 years old, the medication must be given in divided doses.

Example (cont.)Example (cont.)

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Practice

Find the amount to administer, and select appropriate syringe.

Answer: 0.4 mL

Ordered: 0.4 mg Epinephrine stat

On Hand: Epinephrine 1 : 1000 Solution

Use a 0.5 mL tuberculin syringe.

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Practice

Find the amount to administer.

Ordered: Zinacef 500 mg IM

On Hand: Zinacef (cefuroxime for injection) 750 mg reconstituted with 3mL sterile water.

Dosage strength after reconstitution is 225 mg/mL

Answer: 2.2 mLin a standard 3 mL syringe

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Reconstituting Powdered Medications Medications that lose potency quickly in

solution are supplied in powdered form;

are reconstituted using an appropriate diluent.

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Reconstituting Powdered Medications (cont.)

Determine the solvent to be used to dilute medication. Sterile water Saline Bacteriostatic solution

Some meds are packaged with the appropriate solvent.

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Some medications are mixed with lidocaine. This decreases pain on injection.

Label or package insert indicates when lidocaine can be used.

Must have a physician’s order to use it.

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Rule 14-5Rule 14-5 To reconstitute a powdered medication:

1. find the directions;

2. use a sterile syringe and aseptic technique to draw up the diluent;

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3. inject the diluent into the medication vial;

4. agitate the mixture by rolling, inverting, or shaking the vial.

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5. make sure the powdered medication is completely dissolved.

The solution must be free of visible particles.

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Use the specified amount of diluent.

Too much – Dosage strength will be incorrect.

Too little

Powder may not dissolve completely.

Dosage strength will be incorrect.

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Rule 14-6Rule 14-6 When storing a medication after reconstitution:

1. record the date, the time of expiration, and your name or initials;

2. for multiple-dose medications, also record the solution strength.

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Amount of diluent = 5 mL

Route = IV only

Diluent = 0.9% NaCl without preservatives

Instructions = shake to dissolve

Solution strength = 38 mg/mL

Storage = no refrigeration

Example Example

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Ordered: Gemcitabine HCl

125 mg IVSS

On hand: see label

H = 38 mg

Q = 1 mL

D = 125 mL


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Step A No conversion is necessary.

Step B Calculate amount to administer using preferred method.

125 mg / 38 mg x 1 mL = A

3.29 x 1 mL = A

3.3 mL = A


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Step C Dose ordered (125 mg) is greater than 3 time that of dose on hand (38 mg),so 3.3 mL is reasonable.


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Error Alert!

Select the correct instructions for the strength and route ordered.

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PracticeHow much diluent should you add to this vial?

What are the storage instructions?

Answer: 1 mL

Answer: store between 2° and 8° C

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Practice

Ordered: Synagis 75 mg IM Q8H

On hand:

What is the amount to administer?

Answer: 0.75 mL

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Other Medication Administration Forms

Intradermal (ID) injections Small doses given under first layer of skin

0.1mL or less administered with tuberculin syringe

Most often used for diagnostic testing

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Other Medication Administration Forms (cont.)

Drops Also called instillations Deliver medication to

nose, eyes, and ears Administered with droppers Administered with

plastic squeeze bottles

Use equipment that comes with drugs that are administered as drops or sprays.

Sprays Deliver medication

to nose and throat Administered with

plastic squeeze bottles

Administered with atomizers

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Mists Inhaled by patient

Delivered with the

following equipment Vaporizers Nebulizers Meter dose inhalers (MDIs)

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Inhalants Metered dose inhalers

(MDI) An MDI is a

measured doseof medication in a puff.

Read manufacturer’s instructions.

Techniques for use Closed mouth Open mouth Closed mouth

with spacer

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Nebulizers Liquids mixed with sterile saline solution

Single doses (sterile saline must be added)

Single doses premixed with saline Multiple-dose containers (come with

special droppers)

Physician specifies solution strength and amount to administer.


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Vaginal Medications

Douche

Tablet or suppository

Rectal Medications

Enema

Suppository

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Topical medications Applied directly to the skin

Gels Creams Ointments Pastes

Follow manufacturer’s instructions.

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Transdermal Systems Patches

Release liquid medication at a constant rate Dosage strength expressed in mg or mcg per

hour

Ointments and creams

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Practice

Ordered: Transderm Nitro 0.8 mg/h top

On hand: 0.1 mg/h, 0.2 mg/h and 0.6 mg/h

What is the amount to administer?

Answer: 2 patches; 1 – 0.2 mg/h and 1 – 0.6 mg / h

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In Summary

In this chapter you learned to: calculate doses of parenteral medication in

solution and select syringes based on dose calculation.

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In Summary

In this chapter you learned to: calculate doses of medication expressed in

percent or ratio format;

calculate doses of reconstituted parenteral medications.

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In Summary

In this chapter you learned to:

differentiate other medication administration forms and equipment.

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Apply Your Knowledge

How would you interpret a label that reads as follows?

Heparin 1:5000

Answer: Each 1 mL contains 5000 units of heparin.

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What kind of syringe would you use to administer 0.4 mL IM?

What kind of syringe would you use to administer 2.3 mL IM?

Answer: 0.5 mL tuberculin syringe

Answer: 3 mL standard syringe

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What is the maximum amount of medication that can be administered IM in one site to an adult?

Answer: 3 mL

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A 20% solution means that there is 20 g in how many mL?

Answer: 100 mL

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End of Chapter 14

The best

way to escape

from a problem is

to solve it.

-- Alan

Saporta

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© 2012 The McGraw-Hill Companies, Inc. All rights reserved. Chapter 14 Parenteral Dosages and Other Medication Administration Forms PowerPoint ® Presentation