1. Parenteral Dosage of Drugs
Chapter 11

2. Calculation of Drug Dosage: Parenteral

3. Calculation of Drug Dosage: Parenteral
Order
Cleocin 150 mg IM every 12 hours
Available
Cleocin (clindamycin phosphate) 300 mg per 2 mL

4. Calculation of Drug Dosage: Parenteral
Step 1. Convert
No conversion is necessary.

5. Calculation of Drug Dosage: Parenteral
Step 2. Think
You want to give less than 2 mL
Actually, you want to give 150 mg, which is of 300 mg and of 2 mL, or 1 mL
Calculate to double-check your estimate.

6. Calculation of Drug Dosage: Parenteral
Step 3. Calculate

7. Calculation of Drug Dosage: Parenteral
Given intramuscularly every 12 hours
Select a 3 mL syringe
Measure 1 mL of Cleocin 300 mg per 2 mL

8. Ratio-Proportion Method: Parenteral with Conversion
Order: Robinul 150 mcg IM stat
Supply: Robinul 0.2 mg per mL

9. Ratio-Proportion Method: Parenteral with Conversion
Step 1. Convert
Equivalent:

10. Ratio-Proportion Method: Parenteral with Conversion
Step 2. Think
Give less than 1 mL but more than 0.5 mL
Don’t be fooled into thinking 0.2 mg is less than 150 mcg
0.2 mg is more than 150 mcg
0.2 mg = 200 mcg

11. Ratio-Proportion Method: Parenteral with Conversion
Step 3. Calculate

12. Ratio-Proportion Method: Parenteral with Conversion
Given intramuscularly immediately
Select a 1 mL syringe
Measure 0.75 mL Robinul 0.2 mg per mL
You may have to change needles, as this is an IM injection.

13. Guidelines for Syringe Selection
Standard doses more than 1 mL
Round to tenths and measure in a 3 mL syringe
3 mL syringe is calibrated to 0.1 mL increments
1.53 mL is rounded to 1.5 mL
Drawn up in a 3 mL syringe

14. Guidelines for Syringe Selection
Small (less than 1 mL), critical care, or children’s doses
Round to hundredths and measure in 1 mL syringe
1mL syringe is calibrated in 0.01 increments
0.257 mL is rounded to 0.26 mL
Drawn up in a 1 mL syringe

15. Guidelines for Syringe Selection
Amounts of 0.5 –1 mL calculated in tenths
Can be accurately measured in either a 1 mL or 3 mL syringe

16. Insulin Label Concentration Manufacturer Brand Name Storage Species
Type
Generic Name
Expiration Date

17. Combination Insulin Dosage
40 units
NPH
Units-100 insulin
12 units
Regular
Units -100 insulin
Total insulin dosage = 52 units

18. Preparing Combination Insulin Dosage
2. Inject 10 units of air.
Inject 30 units of air.

19. Preparing Combination Insulin Dosage
3. Withdraw
10 units regular.
4. Withdraw
30 units NPH for a total of 40 units.

20. Insulin Sliding Scale Order
Humulin R Regular units-100 insulin subcut based on glucose reading at 1600

21. Insulin Sliding Scale Insulin Dose Glucose Reading* No coverage
Glucose less than 160
2 units
160–220
4 units
221–280
6 units
281–340
8 units
341–400
* Glucose is greater than 400: Hold insulin; call MD stat.