Dosage Calculations Metric Conversion
basic medication dosage calculation
a patient is ordered 50mg of Dilatin PO BID. The unit only has the drug available in a 125mg/10mL concentration. How many milliliters do you give this patient per dose? 50mg ÷ 125mg x 10 mL 0.4 x 10mL = 4mL
Injectable Dosage: A nurse is preparing to administer heparin 8,000 units subcutaneously every 12 hours. Available is heparin injection 10,000 units/mL. How many mL should the nurse administer per dose. Round the answer to the nearest tenth. Use a leading zero if it applies. Do not use a trailing zero
per unit: 8,000 ÷ 10,000 = 0.8 mL
Celcius to Fahrenheit
x9; ÷5; +32 example: 37.8° C = 100° C 37.8 x 9= 340.2 340.2 ÷ 5= 68.04 68.04 + 32= 100.04 Round up to the nearest whole number = 100° F
Fahrenheit to Celcius
-32; ×5; ÷9
2.54 cm
1 inch
1000 g
1 kg
15 gtts
1 mL
1000 mcg
1 mg
240mL
1 cup
12 inches
1 foot
To find drops per minute
gtts/min = divide the amount by the minutes (if hours convert to minutes by multiplying the amount of hours by 60) then multiply by the amount of drops. Linezolid 600 mg IV once a day is ordered for a patient. The linezolid is dissolved in 300 mL of NS and should infuse in 1 hour. Using tubing with a drop factor of 10 gtt/mL, how many drops per minute should the linezolid be infused. 300 mL ÷ 60mins × 10 gtt = 50 gtt/min
Big to small
multiply
Kg to lbs
multiply by 2.2
500 mL
1 pint
1 cm
10 mm
1 kg
1000 g
1 L
1000 mL
1 liter
1000 mL
30mL
1oz
15mL
1tbsp
5mL
1tsp
1 kg
2.2 lbs
An infant who weighs 8 kg is to receive ampicillin 25 mg/kg I.V. every 6 hours. How many milligrams should the nurse administer per dose? Record your answer using a whole number.
25 mg/kg x 8 kg = 200 mg
IV Infusion with Electronic Infusion Pumps: A nurse is preparing to administer dextrose 5% in water (D5W) 500 ml IV to infuse over 4 hours. The nurse set the IV infusion pump to deliver how many mL/hr? Round the answer to the nearest whole number. Use leading zero if it applies. Do not use a trailing zero
500 ÷ 4 = 125 mL
A nurse is preparing to administer cefotaxime 1g intermittent IV bolus over 45 minutes. Available is cefotaxime 1 gram in 100 ml 0.9% sodium chloride (0.9% in see in NaCl). Then nurse should set the IV fusion pump to deliver a how many mL/hr. Round the answer to the nearest whole number
Asking for hours but only showing 45mins. 60mins ÷ 45 mins = 1.333333333 1.333333 x 100 mL = 133.33333 133 mL/hr
Dosage by weight. A nurse is preparing to administer Epoetin 50 units/kg/dose 3 times weekly subcutaneously to a client who weighs a 198 pounds. Epoetin solution is available for injection at 4000 units/mL. How many mL should the nurse administer per dose? (Round the answer to the nearest tenth. Use a leading zero if applicable but do not use a trailing zero)
Convert weight from lbs to kg (198 ÷ 2.2 = 90) Multiply the weight by the ordered amount (90 × 50 = 4,500) Multiply the dose available by the dose desired (4,000 ÷ 4,500 = 1.125 mL) Round to the nearest tenth (1.1 mL)
Right of Medication Administration
Right drug, Right dose, Right time, Right route, Right patient, Right documentation
Small to big
divide
lb to kg
divide by 2.2
how to calculate the intake
mL plus mL (convert oz to mL).... example A patient consumes 2 oz of an ice pop and 30 mL of ice chips during the shift. Intravenous fluids infused at 125 mL/h during the shift. The Foley catheter was emptied of 800 mL at 6 pm. 80 mL were emptied from a drain at 6 pm. Calculate the input for the 6 am to 6 pm shift. add the consumed amounts together 2 oz (1 oz equals 30 mL, 30 times 2 equal 60 mL) plus 30 mL plus 125 mL times (amount of hours) 12 hrs Answer: 1590 mL
how to calculate the output
mL plus mL... example A patient consumes 2 oz of an ice pop and 30 mL of ice chips during the shift. Intravenous fluids infused at 125 mL/h during the shift. The Foley catheter was emptied of 800 mL at 6 pm. 80 mL were emptied from a drain at 6 pm. Calculate the output for the 6 am to 6 pm shift. add the emptied amounts together 800 mL plus 80 mL Answer: 880 mL