Download Parenteral Dosage of Drugs

Parenteral Dosage of Drugs
Chapter 11
MAT 119
Parenteral Routes
• Route of administration other than
gastrointestinal
– Intramuscular (IM)
– Subcutaneous (subcut)
– Intradermal (ID)
– Intravenous (IV)
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Z-Track Injection
Z-Track
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Parenteral Routes
Used to describe drugs given by any route
other than oral, sublingual, topical, or
rectal
• Generally associated with drugs
administered by a needle
• The term “parenteral” means by injection.
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Parenteral Routes
• Benefits: Good for drugs that are poorly
absorbed, rapid response, patient is
uncooperative, unconscious, etc.
• Disadvantage: Expensive, require skilled
personnel, is an invasive technique
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Parenteral Routes
All routes have limitations:
• Limited to solutions, suspensions, and
emulsions
• Must be sterile (bacteria-free)
• pH must be maintained
• May require buffers
• Volume limited (IM, ID, Subcut)
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Parenteral Medications
• Most parenteral medications are prepared
in liquid form and packaged in single, or
multi-dose vials
– Ampules or prefilled syringes
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Parenteral dosages
Round amount to be administered to tenths if
the amount is greater than 1 mL and measure
it in a 3 mL syringe
Order: Administer 1.33 mL = 1.3 mL
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Parenteral dosages
• Measure amounts less than 1 mL rounded to
hundredths and all amounts less than 0.5 mL in
a 1 mL syringe.
• Order: Administer 0.65 mL
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Parenteral dosages
• Amounts of 0.5 mL to 1 mL calculated in tenths
can be accurately measured in either a 1 mL or
a 3 mL syringe (usually use 3 mL for IM > 0.5
mL)
• Order: Administer 0.6 mL
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Calculation of Drug Dosage:
Parenteral
Order: Cleocin 150 mg IM q 12h
Available: Cleocin (clindamycin
phosphate) 300 mg per 2 mL
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Three Steps
• Step 1: Convert
– All units of measurement must be in same
system and all units must be in same size
• Step 2: Think
– Estimate logical amount
• Step 3: Calculate
Dosage on hand = Dosage desired
Amount on hand X amount desired
D desired 
 Q (quanity)  X
H (have)
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Cleocin 150 mg IM q.12h
Available: Cleocin (clindamycin
phosphate) 300 mg per 2 mL
• Step 1: Convert
– No conversion is necessary
• Step 2: Think
– You want to give less than 2 mL
– Actually, you want to give 150 mg, which is
1/2 of 300 mg and 1/2 of 2 mL, or 1 mL
– Calculate to double-check your estimate
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Cleocin 150 mg IM q.12h
Available: Cleocin (clindamycin
phosphate) 300 mg per 2 mL
• Step 3: Calculate
150 mg
D
Q
 2 mL
H
300 mg
 1mL
300 mg = 150 mg
2 mL
X
Give 1 mL Cleocin IM every 12 hours
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Calculation of
Drug Dosage: Parenteral
• Order: Robinul 100 mcg IM stat
• Supply: Robinul 0.2 mg per mL
Convert: Equivalent: 1 mg = 1,000 mcg
0.2 mg = 0.200 = 200 mcg
Think: Give less than 1 mL about 1/2
Don’t be fooled into thinking 0.2 mg is
less than 100 mcg
0.2 mg is more than 100 mcg
0.2 mg = 200 mcg
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continued
• Order: Robinul 100 mcg IM stat
• Supply: Robinul 0.2 mg per mL
Step 3: Calculate:
D
100 mcg
Q 
 1 mL
H
200 mcg
1
 mL  0.5 mL
2
200mcg 100mcg

 X  0.5mL
1mL
X
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continued
•
Give IM
•
Select a 1 mL syringe
•
Measure 0.5 mL Robinul 0.2 mg per mL
•
You have to change needles, as this is
an IM injection.
• Change to
1-1 1/2”
needle
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Insulin Label
Find: Supply dosage/concentration
Total volume
Brand name
Type
Manufacturer
Label alerts
Generic Name
Species
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Insulin
• Supply dosage of insulin is 100 units per
mL
• Abbreviated on label as U-100
• Syringe must also be U-100
• Accuracy is critical
• Nurses must understand and correctly
interpret insulin order and label
• The correct syringe must be selected
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Insulin
Syringes
Standard U-100
50 Lo-Dose U-100
30 Lo-Dose U-100
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Interpreting the Insulin Order
• Brand name, including the species and
action time.
– Rapid-acting (Regular)
– Intermediate-acting (NPH)
– Long-acting (Lantus)
• Supply dosage (concentration and number
of units to be given)
• Route of administration and time or
frequency
– Regular insulin only type to be given IV
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Examples
• Humulin R Regular U-100 insulin 14 units
subcut stat
• Novolin N NPH U-100 insulin 24 units
subcut 1/2 hour ā breakfast
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Types of Insulin
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Other Delivery Systems
Insulin Pump
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Inhaled Insulin
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Insulin Sliding Scale
Insulin Dose
Glucose Reading*
No coverage
2 units
Glucose less than 160
160–220
4 units
6 units
8 units
221–280
281–340
341–400
*Glucose greater than 400: Hold insulin, call MD stat
Order: Humulin R Regular U-100 insulin subcut a.c. based
on sliding scale
p. 229 #26-30
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Insulin: Avoiding Errors
• Check dosage with two nurses
• When combination dosages are prepared,
two nurses must verify each step of the
process.
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