1. Quick Review Chapter 10 Oral dosages of drugs Tablets, capsules
Liquid medications and volume
3 step approach to dosage calculations
Scoring of medication, fewest number of pills, sustained release, enteric coated

2. Step 1 Are the measurements in the same system?
convert
Are the measurements in the same system?
Are the units in the same size?
Math tip: more practical to covert from larger to smaller units (g to mg)

3. Step 2 Does the quantity or volume make sense?
estimate
Does the quantity or volume make sense?
What is the reasonable amount to be administered?

4. Step 3
calculate
Pills or capsules the amount on hand will always equal 1
Liquid meds depend on the concentration or supply dosage

5. Parenteral Dosage of Drugs
Chapter 11
Parenteral Dosage of Drugs

6. Parenteral Route of administration other than gastrointestinal
Intramuscular (IM)
Subcutaneous (SC)
Intradermal (ID) IV
Intramuscular is an injection directly into the muscle
Subcutaneuous means an injection given into the sq tissue
Intravenous is an injection given directly into a vein
when a pt has an iv, meds are typically ordered in that form
Intradermal is an injection given just underneath the skin (allergy test or tb) has the longest absorption time of all routes there fore used for sensitivity tests

7. Parenteral
Most medications prepared in liquid or solution form and packaged in:
Dosage vials
Ampules
Prefilled syringes
Injectable drugs measured in syringes

8. Injectable Solutions IM maximum dose volume for injection: RULE:
Average 150 lb adult = 3 mL
Maximum for deltoid site = 2 mL
Children age 6 to 12 years = 2 mL
Children birth to age 5 years = 1 mL
Need to take into consideration pt’s condition when selecting volume and needle size.

9. Solving Parenteral Dosage Problems
Apply same three steps used when calculating oral dosages
Convert
All units of measurement must be in same system and all units must be in same size
Think
Estimate logical amount
Calculate
Set up ratio between dosage on hand and desired dosage

10. Rules Parenteral dosages
Amounts greater than 1 mL…round amount to be administered (X) to tenths
Measure in 3 mL syringe
Amounts less than 1 mL… round the amount to be administered (X) to hundredths
all amounts less than 0.5 mL
Measure in a 1 mL syringe
Amounts of 0.5 mL to 1 mL calculated in tenths can be accurately measured in either 1 mL or 3 mL syringe
Talk about examples on page

11. 3 mL syringe 2.33 rounded to 2.3 mL

12. 1 mL syringe
0.297 round to 0.3 mL

13. Example One Order: Cleocin 150 mg IM every 12 h
Available: Cleocin 300 mg per 2 mL
How many mL are needed for each dose?
Prompt class to use 3 step approach to solve

14. Example One Convert Think Calculate No conversion necessary
Estimate giving less than 2 mL
Actually want to give 150 mg, which is half of 300 mg and half of 2 mL, or 1 mL
Calculate to double-check estimate
Calculate

15. Example One Calculate Cross-multiply Simplify
Ask class what would be best syringe

16. Example One 1 mL should be given intramuscularly every 12 hours
Select 3 mL syringe
Measure 1 mL of Cleocin from 300 mg per 2 mL (dosage supply) from vial

17. Example Two Order: Robinul 150 mcg IM stat
Available: Robinul 0.2 mg per mL
How many mL are needed for each dose?
Have class use 3 step method…. Convert and think…

18. Example Two Convert Think Equivalent: 1 mg = 1,000 mcg
Give less than 1 mL but more than 0.5 mL
Avoid being fooled into thinking 0.2 mg is less than 150 mcg
0.2 mg is more than 150 mcg
0.2 mg = 200 mcg
Have class calculate

19. Example Two Calculate Cross-multiply Simplify
Ask class what syringe they would choose

20. Example Two 0.75 mL of Robinul is to be given immediately
Select 1 mL syringe
Measure 0.75 mL of Robinul 0.2 mg per mL (dosage supply)
May need to change needles
Due to IM injection
REVIEW SET in class p. 280

21. High-Alert Parenteral Medications
Drugs that bear a heightened risk of causing significant patient harm when they are used in error
Examples:
Heparin*
Insulin*
Heparin and Insulin have been identified as 2 of the highest risk medications for severe error potential…in dosage calculations, fatal dosing errors, reading drug labels incorrectly, making mistakes in filling ADC’s; ALSO
-both used daily in nursing
-both use units (potential for mix up)
-units are usually small…use of incorrect syringe
-may have multidose vials which may look alike
-both given subcut and/or IV

22. Heparin Anticoagulant New label content and design per USP
Strength per total volume as primary expression
Followed by strength per mL
ALWAYS identify the concentration of supply
as well as total volume in container.
Prevents formation of blood clots…aka thrombosis…used as prophylaxis (pre and post surgery)
Page look at labels page 292

23. Insulin Accuracy in insulin preparation/administration is critical!
Inaccuracy can be life threatening!
Essential to read/understand label, interpret order, choose correct insulin syringe!
Is a hormone made in the pancreas necessary for metabolism of glucose, proteins, and fats.
Patients who are deficient in insulin are required to take insulin by daily injection.

24. Insulin Common supply dosage of insulin is 100 units per mL
Abbreviated on label as U-100
Syringe must also be U-100
Is a hormone made in the pancreas necessary for metabolism of glucose, proteins, and fats.
Patients who are deficient in insulin are required to take insulin by daily injection.
Insulin is a ready to use solution measured in UNITS
© Cengage Learning 2016

25. Insulin Syringes 100 unit dose 100 units/1 mL
50 unit low-dose 50 units/0.5 mL
30 unit low-dose 30 units/0.3 mL

26. Insulin Also available as 500 units per mL
Used only in special circumstances for diabetic pt’s marked insulin resistance (daily requirement of > 200 units)
Use extreme caution when administering
Accidental overdose may result in irreversible insulin shock or death
U-500 insulin syringe not available
Use 1 mL syringe

27. Insulin Critical to be accurate
Nurses must understand and correctly interpret insulin order
Identify components of label
Must select correct syringe
Page 296 to look at label identification

28. Interpretation of insulin label
Brand and generic names
Supply dosage or concentration
Other instructions
Have class look at labels page

29. Remember: Two nurses check Insulin at 4 steps: Physician order
Insulin selected
Calculated dose
Dose drawn up

30. Insulin Action and Times
Onset
Peak
Duration
Rapid-acting (lispro, aspart, glulisine)
5 to 15 minutes
45 to 75 minutes
2 to 4 hours
Short-acting (regular)
30 minutes
5 to 8 hours
Intermediate-acting (NPH)
2 hours
6 to 10 hours
18 to 24 hours
Long-acting (detemir, glargine) –
Up to 24 hours
Talk about Regular and NPH insulin first (page 2970
Insulin is categorized by ACTION TIMES, with Onset, Peak, and Duration times
Page 297 looks at the different types of insulin labels and their ACTION TIMES

31. Insulin
An insulin analog is the newest type of insulin that has been chemically modified to act faster or slower than the type of insulin naturally made by the body.
Most people with type 1 diabetes should use insulin analogs to reduce hypoglycemia risk
(American Diabetes Association, 2013)
The rapid acting and long acting analogs

32. Premixed Combination Insulin
Combination of short-acting and intermediate-acting insulin mixed in one vial
Read label carefully to understand each type of insulin and concentration included in combination
Two types that are often mixed:
Regular (R)
NPH (N)
Pre-mixed are used as a CONVENIENCE for pt’s who are in a treatment plan using these 2 insulins which reduce the # of injections daily.
LOOK at labels page

33. Interpreting the Insulin Order
Order must include:
Brand name, generic name, and action time
Supply dosage (concentration) and number of units
Route of administration and time frequency
Example:
Novolin N NPH U-100 insulin 24 units, Subcut, 30 minutes before breakfast daily
Must be written CLEARLY and contain SPECIFIC information to negate errors! (write on board from book, page 299)
Other examples: Humulin R regular U-100 insulin 14 units subcut stat
Page 319 questions 5-10

34. Insulin Sliding Scale Purpose: Order:
To cover or correct elevation in patient’s blood glucose level
Order:
Humulin R U-100 insulin Subcut based on glucose reading at 1600
(Orders are based on algorithms in facility)
This is a special insulin order needed to “cover” a pt’s increasing blood sugar that is not yet regulated.
Because a short onset of action is needed, a rapid acting insulin or short acting insulin will be used.

35. Insulin Correctional Scale
Insulin Dose
Glucose Reading*
No coverage
Glucose less than 160
2 units
160 to 220
4 units
221 to 280
6 units
281 to 340
8 units
341 to 400
If glucose reading is 250, how many units of Humulin R U-100 insulin should be administered?
* If greater than 400, hold insulin and call MD stat
Page 325 questions 36-40

36. Rules for Measuring Insulin in an Insulin Syringe
Measure U-100 insulin in U-100 insulin syringe only
Use U-100 insulin syringes only to measure U-100 insulin
Measure U-500 insulin in 1 mL syringe
Two nurses must check insulin dosage before administration to patient

37. Measuring U-500 Insulin in a 1 mL Syringe
Order: Humulin R U-500 regular insulin units Subcut stat
Available: Humulin R U-500 regular insulin
How many mL are needed?
Calculating Insulin using 3 step approach:
Have class do 1,2,3

38. Measuring U-500 Insulin in a 1 mL Syringe
Convert
Recall that U-500 equals 500 units per mL
Think
There are 500 units in 1 mL
280 units is slightly more than half
Estimate giving a little more than 0.5 mL
Calculate to determine exact amount

39. Measuring U-500 Insulin in a 1 mL Syringe
Calculate
Cross-multiply
Ask class what syringe they will choose
Simplify

40. Measuring U-500 Insulin in a 1 mL Syringe
0.56 mL must be given immediately
Draw up 0.56 mL of Humulin R U-500 regular insulin in 1 mL syringe

41. Combination Insulin Dosing
Two types of insulin prescribed to be administered at same time
Usually rapid- or short-acting and intermediate-acting insulin ordered for same time
If compatible, both insulins can be drawn up into same syringe
Check manufacturer recommendation
Long-acting insulins cannot be mixed in syringe with another insulin
E.g., detemir, glargine

42. Combination Insulin Dosing
Example order:
Novolin N NPH U-100 insulin 40 units and Novolin R U-100 insulin 12 units Subcut before breakfast daily
First determine total number of units needed and choose correct insulin syringe
= total of 52 units
Need standard U-100 insulin syringe

43. Preparing Combination Insulin Dose
Follow clear-to-cloudy rule
Draw up clear insulin (regular) first
Then draw up cloudy (NPH) insulin
Roll vial of cloudy insulin in hands to mix before beginning procedure
If you withdraw too much NPH, you must discard the entire medication and start over
Never combine long-acting insulin with other insulin solutions, as this may be life threatening

44. Procedure for Combining Two Insulins in the Same Syringe
Draw back and inject 40 units of air into NPH insulin vial
Withdraw needle
Draw back and inject 12 units of air into regular insulin vial
Leave needle in vial
Page 307

45. Procedure for Combining Two Insulins in the Same Syringe
Turn vial of U-100 regular insulin upside down and draw out insulin to 12-unit mark
Insert needle into NPH insulin vial and withdraw insulin to 52-unit mark
Page 307 shows example of combining insulins in the syringes

46. Insulin: Avoiding Errors
Check dosage with two nurses **
When combination dosages prepared, two nurses must verify each step of the process **
have class name each step of the process:
Physician order
Insulin selected
Calculated dose
Dose drawn up
REVIEW SET 25: BEGIN WITH QUESTION