1. Chapter 12
Objectives
Calculate dosages using the dosage formula and/or dimensional analysis
Use drug labels to gather dosage information to calculate the supply on hand
Shade syringes to the proper dosage per the doctor’s order
Convert among systems to calculate dosages
Convert a drug order to the format of the supply on hand
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2. Parenteral Dosage
Unit 12

3. Parenteral Dosage Page 253
Parenteral medications are not taken orally. Instead, these medications may be in the form of injections, inhalants, patches, or suppositories. The common parenteral routes are:
Route
Abbreviation
Entry point
intradermal ID
between the layers of skin
intramuscular IM
into a muscle
intravenous IV
into a vein
subcutanous
sub-Q
under the skin
Another abbreviation that is off limits for charting

4. Pages 255 – 256
Injections
Injections are mixtures of pure drug dissolved in an appropriate liquid. The dosage or solution strength will be be provided on the medication label and will be given in milligrams per milliliter as a ratio or as a percent. It is important to remember that parenteral doses are calculated based on the amount of drug contained in a specific volume of solution. Parenteral dosages are prescribed in grams (g), milligrams (mg), units, or in milliequivalents (mEq).
Example of Dosage
Given Form
Dosage Interpretation
Neurontin 250 milligrams/ 5 milliliter
milligram per milliliter
5 milliliters contains 250 milligrams of Neurontin
Epinephrine 1 : 1000
ratio
1000 milliliters contains 1 gram of Epinephrine
Lidocaine 2.5%
percent
100 milliliters contains 2.5 grams of Lidocaine
The Do Not Use List from the Joint Commission suggests that the abbreviation for “units” not be used. Just write “units”.

5. Syringes Page 256 Continue to next slide
3 cubic centimeter per milliliter syringe
1 milliliter per milliliter syringe, which is also called the tubercullin syringe
The insulin syringe, which come in various sizes. The dilution of insulin is such that 1 milliliter of insulin fluid has 100 standard units of insulin.
Note that “cubic centimeter” is not used much anymore, as it has been replaced with “millililiter.”

6. IM Injection Guidelines
Page 257
IM Injection Guidelines
There are guidelines for maximum volumes for injection sites.
This is important for accurate dosage calculation and consideration of multiple syringes.
Any dosage larger than the recommended amount is usually checked and verified with the physician, and the dosage is then divided equally or as close to equal as possible and given in two separate injection sites.
Continue to next slide
Client
AGE
Maximum Dos Per Site
Adult
12+
3 milliliters IM deltoid arm
Child
6-12 years
2 milliliters
0-5 years
1 milliliter
Infant
Premature
0.5 milliliter

7. Units of Measures Pages 257 – 258 dosage (D) supply on hand (H)
To calculate the dosage, there are several means of getting to the correct dose. One may use the dosage formula, ratio and proportion, or dimensional analysis. Choose your favorite and stick with it.
dosage (D)
supply on hand (H)
medication
given x
quantity (Q) =
Examples – pages – practice 1: evens
Group work – pages – practice 1: odds
dosage (D) : medication given :: supply on hand (H): quantity (Q)
quantity (Q)
supply on hand (H)
dosage (D) 1
medication
given x =