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Dosage Calculations Practice
1 Dram = _____ mL - ---------------ANS: 4 1 gm = _____ gr. - ---------------ANS: 15 1 grain = ___ mg - ---------------ANS: 64.8 mg (60) 1/4 gr. = _____ mg - ---------------ANS: Answer: 15 Convert 1/4 to a decimal => 0.25, then solve 2 gm = _____ gr. - ---------------ANS: 30 A child weighs 10 lb 2 oz. What is their weight in kg? - ---------------ANS: 1. First, convert the 2 oz to lbs. 2 oz is 0.1 lbs. This gives you 10.1 lbs.
- Now convert 10.1 lbs to kg.
- Answer: 4.59 => 4.6 kg A patient has a bottle of warfarin (Coumadin) 5 mg tablets at home. After his most recent international normalized ratio (INR), the doctor calls and tells him to take 7. mg/day. How many tablets (scored) should the patient take? - ---------------ANS: 1. Calculate the patient's total urinary output for the shift. The patient has continuous bladder irrigation and a Foley catheter. 0800-1000: 3 Liters of bladder irrigation 1000: emptied Foley catheter 3600 mL 1100: 1 Liter of bladder irrigation 1200: 2 Liters of bladder irrigation and emptied 3250 mL from Foley catheter 1300: 1 Liter of bladder irrigation 1400: 1 Liter of bladder irrigation 1500: 1 Liter of bladder irrigation and emptied 3120 mL from Foley Catheter 1600-1900: 3 Liters of bladder irrigation 1900: emptied 4200 mL from Foley catheter - ---------------ANS: Intake: 2170 mL Remember, irrigation in NOT urine. You can not count it. The patient received 3000 mL of irrigation from 0800-1000. When the Foley cath was emptied at 10, there was
a total of 3600 mL. 3000 mL of that was irrigation fluid. Only 600 mL was urine and considered output. Calculate the patients INTAKE during your 12-hour shift. 0800: Two pieces of toast, 2 cups of oatmeal, 8 oz yogurt, 12 oz orange juice, 2 oz grits 1000: Two 8 oz of coffee w/ 2 oz of cream in each 1100: 24 oz of ice chips 1200: IV infusion of Zosyn 50 mL, 2 mL IV push Zofran and 10 cc saline IV flush 1230: house salad, 12 oz soda, three 12 oz popsicles 1400: One pack of red blood cells (250 mL) 1500: 2 mL Morphine and 10 cc saline flush IV 1715: 10 cc saline flush IV 1600-1900: Normal Saline IV 100 cc/hr - ---------------ANS: Intake: 3394 mL Remember, intake is measured in mL. Convert all ounces to mL. 1 oz = 30 mL Also, ice melts to ONE HALF the total ounces. So, 24 ounces of ice melts to 12 ounces. Do NOT count solids like the toast, oatmeal, yogurt, grits, or salad. It has to be liquid at room temp to be counted. Convert 0.3 g to kg. - ---------------ANS: 300 Convert 0.3 g to mg. - ---------------ANS: Answer: 300 mg Since milli means 1000, just move the decimal 3 spots to the right. Or, set up an equation as follows: We know 1 g = 1000 mg. 1 g/1000 mg = 0.3 g/x Solve for x by cross mulitiplying. Convert 0.625 to a fraction. - ---------------ANS: Write down 0.625 over 1. (0.625/1) Multiply the top and bottom by 1000. You are multiplying by 1000 because there are 3 digits after the decimal. If there were only 1 digit, you would multiply by 10. If there were 2 digits, you would multiply by 100. 4 digits would be 10000 and so on.
Convert 8 lbs 4 oz to kg. - ---------------ANS: 3.8 kg Convert 89 kg to lbs. - ---------------ANS: 195. During your 12-hour shift from 7p - 7a, what is your patient's INTAKE and OUTPUT? 2000-0600: Jevity 50 mL/hr 0615: 50 cc free water flush 2100-0215: Two 250 mL of red blood cells 0115: 20 cc saline flush IV 0300: Zosyn IV 50 mL 0400: 10 cc saline flush IV Continuous Fluids: Heparin 10 mL/hr Normal Saline 100 mL/hr Ileostomy: 300 mL NG suction: 50 cc Urine: 1850 mL Wound vac: 100 cc - ---------------ANS: Intake: 2450 mL Output: 2300 mL Remember that 1 cc = 1 mL Notice that the Jevity is running at 50 mL/h for 10 hours, so that is a total of 500 mL. Continuous fluids are constant and run your entire shift. gr. X = _____ mg - ---------------ANS: Answer: 600 mg In this problem, X represents the roman numeral 10. So, the question is asking how many mg in 10 grains. 1 grain = 60 mg, so 10 grains = 600 mg How many grams are in a kilogram? - ---------------ANS: 1000 How many mcg in a mg? - ---------------ANS: 1000 How many mL in a cup? - ---------------ANS: 240
How many mL in a pint? - ---------------ANS: Answer: 480 (500) 16 oz x 30 mL = 480, but study materials say 500 How many mL in a tablespoon (T or tbs)? - ---------------ANS: 15 How many mL in a teaspoon (tsp)? - ---------------ANS: 5 How many mL in one ounce? - ---------------ANS: 30 How many ounces are in a pint? - ---------------ANS: 16 How many ounces are in a pound? - ---------------ANS: 16 How many ounces in a cup? - ---------------ANS: 8 How many pints are in a quart? - ---------------ANS: 2 How many pounds are in a kilogram? - ---------------ANS: 2. How many teaspoons are in a tablespoon? - ---------------ANS: 3 How would you write 1000 mg/1 g as a ratio? - ---------------ANS: 1000 mg : 1 g http://www.cwladis.com/math104/lecture3.php Scroll down to find some examples on reading labels. - ---------------ANS: If your IV bag says 5% dextrose solution, what does the 5% represent? - --------------- ANS: There are 5 g of dextrose per 100 ml in the bag. Know how to read labels. Info on label: NDC 0009-0856- 1mL Hemabate (large purple type)
The patient weighs 10 kg. Is this order safe? - ---------------ANS: 1. First, calculate the minimum and maximum dose per day. The minimum amount would be 200 mg. ( x 10) The maximum amount would be 400 mg. (40 x 10)
- Now, since the dose is given every 8 hours, divide the minimum and maximum by 3, since 3 doses can be given in one day (24 hours). The minimum single dose is 66.7 mg, and the maximum single dose is 133.3 mg.
- NO, the ordered dose is not safe. The doctor ordered 200 mg for a single dose which is more than the maximum allowed single dose of 133.3 mg. Order: Ampicillin 500 mg IV in 50 mL in D5 1/2NS in 30 minutes. What is the infusion rate in mL/h? - ---------------ANS: Answer: 100 mL/h Divide total mL by total minutes, then multiply by 60. (total mL ordered/total minutes) x 60 minutes (50 mL/30 min) x 60min 1.67 x 60 = 100.2 => 100 mL/h OR Convert 30 min to hours. 30 min = 0.5 hours 50 mL/0.5 = 100 mL/h Order: Ancef 2 gm IVPB in 100 mL D5W in 45 minutes What is the infusion rate? - ---------------ANS: Answer: 133 mL/h (100/45) x 60 = 133.3 => 133 Order: Armour Thyroid gr. X by mouth daily Supply: 300 mg tablets How many tablets will you administer per dose? - ---------------ANS: Answer: 2
Convert the grains to mg. gr. X means 10 grains. Since 1 grain = 60 mg, 10 grains = 600 mg, so you need 2 tablets. Order: Biaxin 200 mg p.o. q 12 h for a child who weighs 45 lbs. Have: Biaxin 125 mg per 5 mL Biaxin label states 15 mg/kg/day in two equal doses. Is this dosage safe? - ---------------ANS: 1. Convert lbs to kgs. 45lbs = 20.5 kg
- Calculate the recommended dose per day. A child weighing 20.5 kg can have 307.5 mg PER DAY. So, divide 307.5 by 2 to get a single dose. So, the maximum single dose is 153.75 mg.
- NO, the ordered dose is not safe. The doctor ordered 200 mg which is more than 153.75 mg. Order: D5LR 1250 mL IV over 8 hours. What is the infusion rate in mL/h? - ---------------ANS: Answer: 156 mL/h Divide 1250 by 8 156.25 => 156 Order: D5W IV at 125 mL/h Drop factor: 10 gtt/mL Calculate flow rate in gtt/min. - ---------------ANS: Answer: 21 gtt/min (volume in mL/time in min) x drop factor (125/60) x 10 2.08 x 10 = 20.8 => 21 Order: Diazepam 5 mg IV for q 6 h for agitation as needed Supply: gr. iss/2mL (the ss has a line over the top) How many mL will you administer per dose? - ---------------ANS: Answer: 0.1 mL
250 mL divided by 4 is 62.5. Round to the nearest whole number. Order: Tylenol 1 gm by mouth q 6 h as needed for pain Supply: 5 gr. capsules How many capsules will you give? - ---------------ANS: Answer: 3 Convert 1 gm to grains. 1 gm = 15 grains. So, you need 3 of the 5 gr. capsules to make 15 gr. The MD orders your patient to start an IV Heparin drip at 18 units/kg/hr and to administer a loading bolus dose of 30 units/kg IV before initiation of the drip. You're supplied with a Heparin bag that reads 25,000 units/500 mL. The patient weighs 172 lbs. What is the flow rate you will set the IV pump at (mL/hr) and the amount of units for the IV bolus? - ---------------ANS: Answer: 28 mL/h, Bolus: 2346 units First, convert 172 lbs to kg. 172 lbs = 78.2 kg The doctor wants 18 units per kg. So, multiply 78.2 by 18 to get 1407.6 units. Set up your equation. I set up my equations by putting what I NEED = to what I am SUPPLIED. x (mL needed) over 1407.6 mg = 500 mL over 25000 units Solve for x by cross multiplying. For the bolus, you will multiply 30 by 78.2 and get 2346. The patient's output is 2025 mL during your 12-hour shift. If the patient had an intake of 3394 mL, what should you monitor the patient for as the nurse? A. Fluid volume overload B. Dehydration C. These findings are within normal limits. Continue to monitor. - ---------------ANS: A Tridil is infusing at 15 mL/hr on an infusion pump. The drug is mixed 50 mg in 500 mL DsW. How many mcg/min is the patient receiving? - ---------------ANS: Answer: 25 mcg/min First, convert the 50 mg to mcg. 50 mg = 50,000 mcg
Now, how many mcg is in 1 mL? 50,000 mcg/500 mL = 100 mcg/mL Now, how many mcg/hr is the pt receiving? 100 mcg x 15 mL = 1,500 mcg/hr So, 1500 mcg/60 min = 25 mcg/min What is 0030 in regular time? - ---------------ANS: 12:30 A.M. What is 3:00 P.M. in military time? - ---------------ANS: 1500 What is the BMI for Mr. Jones weighing 210 lbs with a height of 6 feet, 3 inches? - ---------------ANS: Answer: 26.3 kg/m Convert lbs to kg. 220 lbs = 95.45 kg Convert height to meters. 6'3" = 75 inches 75" = 190.5 cm 190.5 cm = 1.905 meters Square the height...1.905 meters x 1.905 meters is 3. BMI is calculated by dividing the weight in kg by the height in meters squared. 95.45/3.63 = 26. You are caring for a patient at home who must take magnesium hydroxide/aluminum hydroxide (Maalox) 30 mL PO. How many tbsp will you instruct the patient to take? - ---------------ANS: 2 You have an IVPB of ranitidine (Zantac) 50 mg in 50 mL D5W to run over 30 minutes. The tubing has a drip factor of 15. How many drops per minute will you set on the IV infusion controller? - ---------------ANS: Answer: 25 gtt/min (volume in mL/time in min) x drip factor (50/30) x 15 1.67 x 15 = 25.05 => 25
the PTT in 6 hours. The patient is currently receiving a Heparin drip at 22 units/kg/hr from a bag that reads 25,000 units/250 mL. The patient weighs 129 lbs. How many units will the patient receive as a bolus, and how many units per kilogram per hour will the patient receive based on the new PTT result? - ---------------ANS: Answer: bolus will be 1758 units, increase drip to 24 units/kg/h Convert 129 lbs to kg => 58.6 kg To calculate the bolus, multiply 58.6 by 30 to get 1758 Your shift is from 7a-7p. The patient had the following intake and output during your shift. Based on your calculation, the patient is at risk for? 0800: 8 oz orange juice, 6 oz yogurt, slice of bread, 10 cc flush 1000: 8 oz coffee w/ 1 oz of cream 1200: 12 oz soda, Two 12 oz cherry popsicles, 3 oz chocolate pudding, 4 oz chicken broth 1300: 6 oz soda, 12 oz custard 1600: 8 oz ice chips 1400-1900: 50 cc/hr IV infusion 0700: 500 cc urine 1100: emesis 100 cc, ileostomy stool 350 cc 1200: wound vac drainage 200 cc 1300: 250 cc urine 1500: JP drain 400 cc 1700: 350 cc urine 1730: 400 cc urine 1800: 350 cc urine 1830: ileostomy stool 400 cc 1845: 500 cc urine A. Intake: 2080 mL & Output: 3520 mL; monitor the patient for dehydration B. Intake: 2270 mL & Output: 3800 mL; monitor the patient for dehydration C. Intake: 3890 mL & Output: 2200; monitor the patient for fluid volume overload D. Intake: 4005 mL & Output: 2270 mL - ---------------ANS: Answer: B Do not count solids like yogurt, bread, pudding, or custard. Intake and output is measured in mL. Convert ounces to mL. 1 oz = 30 mL
Stool from an ileostomy is usually mostly liquid. Count it as output.
