Dimensional Analysis and Drug Dosage Calculations Converting Units DIMENSIONAL ANALYSIS Changing from one unit to another unit requires: 1) Same type of measurement - you cannot convert length into mass

2) A conversion factor Conversion Factors Mathematical Ratio of the two units you are converting Ex: Conversion of inches to centimeters 1 inch = 2.54 cm Possible Conversion Factors 1 in or 2.54 cm

2.54 cm 1 in Choose the conversion factor that puts what you are converting to over what you are converting from Fence Post Method Covert 15.0 ft to cm Fence Post Method Covert 15.0 ft to cm

Fence Post Method Covert 15.0 ft to cm 15. 0 ft Fence Post Method Covert 15.0 ft to cm 15. 0 ft

12 in 1ft Fence Post Method Covert 15.0 ft to cm 15. 0 ft 12 in 1ft

2.54 cm 1 in Fence Post Method Covert 15.0 ft to cm 15. 0 ft 12 in 1ft

2.54 cm 1 in Fence Post Method Covert 15.0 ft to cm 15. 0 ft 12 in

1ft 2.54 cm 1 in = 457 cm Conversion Examples $12.00 to quarters

56 yards to feet 67 dimes to quarters 18.57 kg to mg 19.84 ft to m 12 450 mL to L 48 quarters 168 feet 26.8 quarters 1.857 X 107 mg

6.047 m 12.45 L Multiple Dimensions The number of dimensions determines the number of conversions Area is two dimensions (length x width) so two conversions are needed 12.5 m2 to cm2 25.0 ft3 to cm3

Conversions in the Denominator Unlike numerator conversions where what you want goes over what you have, denominator conversions are opposite = what you want goes under what you have Basically, the units have to cancel the beauty of the fence post method

Conversion Examples 55.0 g/L to g/mL 25.0 mi/hr to ft/sec 30.0 kg/m2 to g/cm2 0.055 g/mL 36.7 ft/sec 3.00 g/cm2 Drug Dosage Calculation

Reading Drug Labels Amount and Form NDC Number Trade Name Generic Name Contraindications

Storage Directions Manufacturer Dosage Strength Drug Labels 1. Trade Name: Brand name or proprietary name

2. Generic Name: Official name of drug 3. NDC number: identifies the labeler, product, and trade package size 4. Dosage Strength: amount per unit measure 5. Form: capsule, tablet, liquid.. 6. Route: administration pathway 7. Amount: Number of doses 8. Directions: Storage directions 9. Contraindicators: the DO NOTs of the meds 1. Name:

1.Trade 2. Generic Name: 3. Dosage Strength: 4. Form: 5. Amount: 6. Route: 7. Directions: 8. NDC Number: 9. Contraindicators: Cost Comparison

(Amazon.com) Aleve: 270 tablets for $16.40 Naproxen Sodium: 400 tablets for $13.77 Drug Dosage Calculations Calculation of Oral Dosage po = by mouth Ex: Prescription Augmentin 500 mg po daily

Ex: Prescription Augmentin 500 mg po daily 500 mg Ex: Prescription Augmentin 500 mg po daily 500 mg 1 tablet

250 mg Ex: Prescription Augmentin 500 mg po daily 500 mg 1 tablet 250 mg = 2 tablets

Examples 1) The order states Kantrex (antibiotic) 400 mg IM q12 h. The drug is supplied as 0.5 g/2 mL. How many mL should be administered? Examples The order states Kantrex 400 mg IM q12 h. The drug is supplied as 0.5 g/2 mL. How many mL should be administered?

IM = q12 h = Examples The order states Kantrex 400 mg IM q12 h. The drug is supplied as 0.5 g/2 mL. How many mL should be administered? IM = Intramuscular q12 h = every 12 hours 400 mg

400 mg 1g 1000 mg 400 mg 1g 1000 mg

2.0 mL 0.5 g 400 mg 1g 1000 mg 2.0

mL 0.5 g 400 mg 1g 1000 mg 2.0 mL

0.5 g = 1.6 mL Every 12 hrs A patient has an order for enalprilat (blood pressure medicine)0.625 mg daily IVPB (intravenous piggy back). The entralprilat is diluted to 50 mL of D5W (dextrose 5% in

water) and is to be infused over 20 minutes. The tubing drop factor is 60 gtt/mL. At what rate, in drops per minute, should the IVPB be programmed? All the med goes into the 50 mL. Not calculating the dose (that is 0.625 mg), you are calculating the rate that it is administered. Therefore you are calculating 50 mL in 20 minutes at a rate of 60 gtts/min.

50.0 mL 20.0 min All the med goes into the 50 mL. Not calculating the dose (that is 0.625 mg), you are calculating the rate that it is administered. Therefore you are calculating 50 mL in 20

minutes at a rate of 60 gtts/min. 50.0 60 gtt 20.0 mL mL min

All the med goes into the 50 mL. Not calculating the dose (that is 0.625 mg), you are calculating the rate that it is administered. Therefore you are calculating 50 mL in 20 minutes at a rate of 60 gtts/min. 50.0 mL 20.0

min 60 gtt mL = 150 gtt/min Review Problem A patient is receiving dopamine at 12 mL/ h. The concentration of dopamine is 200 mg in 250 mL of 0.9% NS. Calculate the

micrograms per kilogram per minute. The patients weigh is 70kg. Pediatric Dosage Calculation 1. Convert weight of child to kilograms. 2.2 pounds = 1 kg 2. Find the S&T (Safe and Therapeutic Dose Range) of the medicine. 3. Calculate the S&T range for the child and compare to the prescribed order.

Examples Calculate the S&T dose range of ibuprofen for a child who weighs 36 lbs. Ibuprofen is available 100 mg/5mL. How many mL would you administer for the ordered dose to be S&T if that range is 5 to 10 mg/kg/dose q6-8 h? Examples Calculate the S&T dose range of ibuprofen

for a child who weighs 36 lbs. Ibuprofen is available 100 mg/5mL. How many mL would you administer for the ordered dose to be S&T if that range is 5 to 10 mg/kg/dose q6-8 h? 36 lbs 1 Kg 2.2 lbs Examples

Calculate the S&T dose range of ibuprofen for a child who weighs 36.0 lbs. Ibuprofen is available 100 mg/5mL. How many mL would you administer for the ordered dose to be S&T if that range is 5 to 10 mg/kg/dose q6-8 h? 36.0 lbs 1 Kg 2.2 lbs

= 16.4 Kg Examples Calculate the S&T dose range of ibuprofen for a child who weighs 36.0 lbs. Ibuprofen is available 100 mg/5mL. How many mL would you administer for the ordered dose to be S&T if that range is 5 to 10 mg/kg/dose h? 16.4 Kg

5 q6-8 mg 1Kg 16.4 Kg 10 mg 1Kg Examples Calculate the S&T dose range of ibuprofen for a child who weighs 36.0 lbs. Ibuprofen

is available 100 mg/5mL. How many mL would you administer for the ordered dose to be S&T if that range is 5 to 10 mg/kg/dose h?5 mL 16.4 Kg 5 q6-8 mg 1Kg 16.4 Kg

10 mg 1Kg 100 mg = 4.1 mL 5 mL 100 mg = 8.2 mL

36.0 lbs 1 Kg 5 mg 5 mL 2.2 lbs

1Kg 100 mg = 4.1 mL An infant is admitted to the hospital to rule out sepsis. The infant weighs 8 lbs and ampicillin is prescribed. Calculate the S&T 24 hour dosage range for this infant with a possible severe infection. The

recommended dose is 200 to 400 mg/kg/24 h. Obstetric Dosage The physician ordered 1000 mL D5W with 10 units oxytocin intravenously. Begin at 1 mU/min (mU = milliunit, 1000 milliunits = 1 unit) and then increase by 1 mU/min every 30 minutes until contraction begin. The maximum dose is 20 mU/min. Calculate the beginning IV rate (mL/hr).

The physician ordered 1000 mL D5W with 10 units oxytocin intravenously. Begin at 1 mU/min (mU = milliunit, 1000 milliunits = 1 unit) and then increase by 1 mU/min every 30 minutes until contraction begin. The maximum dose is 20 mU/min. Calculate the beginning IV rate (mL/hr). 1 mU min

= hr mL/ The physician ordered 1000 mL D5W with 10 units oxytocin intravenously. Begin at 1 mU/min (mU = milliunit, 1000 milliunits = 1 unit) and then increase by 1 mU/min every 30 minutes until contraction begin. The maximum dose is 20 mU/min.

Calculate the beginning IV rate (mL/hr). 1 mU min 60 min 1 hr = hr mL/

The physician ordered 1000 mL D5W with 10 units oxytocin intravenously. Begin at 1 mU/min (mU = milliunits, 1000 milliunits= 1 unit) and then increase by 1 mU/min every 30 minutes until contraction begin. The maximum dose is 20 mU/min. Calculate the beginning IV rate (mL/hr). 1 mU min

60 min 1 unit 1 hr 1000 mU = hr

mL/ The physician ordered 1000 mL D5W with 10 units oxytocin intravenously. Begin at 1 mU/min (mU = milliunit, 1000 milliunits = 1 unit) and then increase by 1 mU/min every 30 minutes until contraction begin. The maximum dose is 20 mU/min. Calculate the beginning IV rate (mL/hr). 1 mU

min 60 min 1 unit 1000 mL 1 hr 1000

mU 10 unit = hr mL/ The physician ordered 1000 mL D5W with 10 units oxytocin intravenously. Begin at 1

mU/min (mU = milliunit, 1000 milliunits = 1 unit) and then increase by 1 mU/min every 30 minutes until contraction begin. The maximum dose is 20 mU/min. Calculate the beginning IV rate (mL/hr). 1 mU min 60 min 1 unit

1000 mL 1 hr 1000 mU 10 unit = 6 mL/hr

What is the maximum IV rate (mL/hr)? The physician has ordered 500 mL D5W with 20 units oxytocin IV. Begin at 1 mU/min and then increase by 1 mU/min every 30 minutes until contraction begin. The maximum dose is 30 mU/min. What is the initial and maximum flow rate for the IV (mL/hr)?

IV + Bolus Dosage Bolus: a larger, more concentrated dose given prior to the steady IV dose to help speed response time It is also the mushy ball of chewed food that you swallow. But these are not the same thing. The physician has ordered 1000 mL lactated Ringers with 20 g magnesium sulfate. You are to administer a bolus with

4g/30 min, then maintain a continuous infusion at 2g/h. 1) Calculate the IV rate (mL/h) for the bolus order. 2) Calculate the continuous rate (mL/h). The physician order Amikacin 150 mg IM q8 h. The following is available. How many mL should be administered?