Pharmacy Calculations
How many milliliters of a stock solution of 1:750 benzalkonium chloride are required to prepare 15 mL of a 0.01 % w/v ophthalmic solution? Round to 1 decimal place.
0.0015
What is the labelled strength of epinephrine hydrochloride in a 50 gram of a topical gel containing 50 mg of epinephrine hydrochloride? Round to 2 decimal places.
0.1%
A prescription calls for the preparation of 15 mL of a 0.5% tobramycin ophthalmic solution. How many grams of sodium chloride should be included in the formulation to make it isotonic with tears. (The sodium chloride equivalent for tobramycin is 0.07.) Round to 2 decimal places.
0.13 g NaCl to add
A prescription calls for the preparation of 30 mL of a 2% tropicamide ophthalmic solution. How many grams of sodium chloride should be included in the formulation to make it isotonic with tears. (The sodium chloride equivalent for tropicamide is 0.11.) Round to 3 decimal places.
0.204 g NaCl to add
3) What is the percentage strength % w/v of a 90 mL of an aqueous solution containing 200 mg sodium benzoate? Round to 2 decimal places.
0.22%
How many sildenafil 50 mg tablets are required to prepare 25 mL of compounded 0.2% sildenafil otic drops?
1 tab
A prescription for a testosterone gel includes 1.2 mL of the surfactant polysorbate 80. How many grams does polysorbate 80 contribute to the total weight of the preparation? (The specific gravity of polysorbate 80 = 1.08). Round to 1 decimal place.
1.3 PS 80
How many grams of precipitated sulfur powder should be mixed with 60 grams of an 8% sulfur ointment to prepare a 10% sulfur ointment? Round to 2 decimal places.
1.33 g sulf
Gemcitabine was prescribed for a 62-inch, 112-pound female with ovarian cancer, to be infused at a dose of 1,000 mg/m2 over a 30-minute period. Calculate the dose for this patient. Round to a whole number.
1.489 m^2
Gentamicin sulfate is prescribed for IV infusion at a dose of 2.5 mg/kg for a 1.5 kg neonate. Calculate the dose and the pump rate (mL/min) if the dose will be in a 50 mL IV bag and it is administered over a 30-minute period. Round to 1 decimal place.
1.7ml/min
What would be the resulting strength of 500 mL of a 25% v/v ethanol solution is diluted to 1.2 L?
10.4 %
How many milliequivalents of chloride ion are provided in a 10 mL vial of 10% calcium chloride dihydrate (calcium chloride dihydrate, MW = 147)? Round to a whole number.
14 mEq Cl
How many milligrams of indomethacin sodium trihydrate (MW 433.8) should be weighed to prepare a 120 mL solution of 1 mg/mL indomethacin (MW 357.8)? Round to 1 decimal place.
145.5 mg
A TPN formula includes 9 mMol of sodium phosphate (Na3PO4). How many mEq of sodium are provided by this amount of sodium phosphate (MW = 164)? Round to a whole number.
15 mL inj
A prescription for one-liter bag of an IV admixture requires 60 mEq of sodium chloride. How many mL of sodium chloride injection, 23.4% should be added to the bag? (MW NaCl = 58.5) Round to a whole number.
15 ml
How many grams of sodium chloride are required to prepare 120 mL of a 25 mEq/mL sodium chloride solution? (MW NaCl = 58.5) Round to a whole number.
176 g NaCl
A vaginal cream contains 0.01% w/w dienestrol. Express this concentration as a ratio strength, with the first figure in the ratio being 1.
1: 10,000
If 45 mL of a 5% drug suspension is diluted to 60 mL, what is the concentration of the 60 mL suspension? Round to 2 decimal places.
2.25 g
Calculate the theoretical osmolarity of an 8.4% sodium bicarbonate (MW = 84) solution. Round to a whole number.
2000 mOsm SB/L * sol
A patient is prescribed lithium carbonate 300 mg tabs, 1 tab po tid. How many milliequivalents of Li+ is the patient consuming each day? (Li2CO3 MW 74). Round to a whole number.
24 mEw Li /day
A pharmacist is asked to prepare a metronidazole benzoate oral suspension equivalent in concentration to 20 mg/mL of the free base form of metronidazole (MW 171.2). How many grams of the benzoate form (MW 275.3) should be weighed to prepare 100 mL of this suspension? Round to 1 decimal place.
3.2 g
How many grams of niacinamide are required to prepare 90 g of a 4% acne gel? Round to 1 decimal place.
3.6 niac
An order for 2 grams lidocaine in 500 mL of D5W is to be administered intravenously at a rate of 2 mg per minute via an infusion pump. Calculate the flow rate, in mL per hour, to program the pump. Round to a whole number
30 ml/hr
A 10-year-old, 65-pound child was prescribed valproic acid syrup 250 mg/5 mL at a dose of 150 mg PO bid. The recommended dosage range is 10 to 15 mg/kg/day up to a maximum of 60 mg/kg/day. Calculate the daily dosage range for this child and state whether the child's daily dose is within the proper range.
300 mg /day
How long (hr) will it take a 700 mL of an IV fluid to infuse if it is running at 25 drops per min using an administration set with a drop factor of 15? Round to a whole number.
31 mL/hr
How many grams of calcium chloride dihydrate (CaCl2-2H2O) would be needed to produce 90 mOsm of CaCl2? (FW for CaCl2-2H2O = 147. Note: Water of hydration becomes part of the solvent water, so is not osmotically active.) Round to 2 decimal places.
4.41 g CCD
A prescription calls for the preparation of 200 mg / mL solution of ceftriaxone for IM injection. You have a vial of ceftriaxone sodium for injection, a sterile powder containing 1 g of ceftriaxone, such that reconstitution with 3.6 mL of diluent will yield a ceftriaxone concentration of 250 mg/mL. How many milliliters of diluent should be added to the powder to produce a concentration of 200 mg/mL? Round to 1 decimal place.
4.6 mL
A prescription is written for 160 mg/5 mL amoxicillin oral suspension. You will prepare it using amoxicillin powder for suspension, 200 mg/5 mL. The label on the container states that 39 mL of water are to be added to reconstitute the powder to produce 50 mL of a 200 mg/5 mL oral suspension. How much water (mL) should be added to produce the requested 160 mg/5 mL suspension? Round to 1 decimal place.
51.5 ml
C. S. is a 26-inch, 15 kg girl with neuroblastoma. Calculate her dose of cisplatin, prescribed as of 60 mg/m2 by IV infusion. Round to a whole number.
66 cm
The intravenous dose of mannitol is 1.5 g/kg of body weight, administered as a 15% (w/v) solution. How many milliliters of solution should be administered to a 150 lb patient? Round to a whole number.
682 mL sol
One liter of a 0.3% intravenous infusion of potassium chloride is to be infused over 4 hours. If the drip chamber delivers 20 drops/mL, calculate the rate of flow in drops per minute, needed to administer the infusion over the desired time interval. Round to a whole number.
7 hr
How many milliliters of mineral oil are contained in 1 tablespoonful of Kondremul (55% mineral oilmicroemulsion)? Round to 1 decimal place.
8.3 mL
Calculate the theoretical osmolarity (mOsm/L) of 23.4 % sodium chloride injection (MW NaCl = 58.5). Round to a whole number.
8000 mOsm NaCl/L * sol
Calculate the theoretical osmolarity of a 15% w/v mannitol (MW = 182) solution? Round to a whole number.
824 mOsm mann/L * sol
What will be the flow rate (mL/hr) of an IV infusion with a concentration of 50 mg in 500 mL at a rate of 1 mcg/kg/min to a 51 kg patient? Round to a whole number.
83 drops inf /min
Cefazolin was prescribed as 125 mg q6h for a child weighing 40 lbs. The manufacture recommends 25 to 50 mg/kg/day divided into 4 doses. Calculate the manufacture-recommended dosage range per dose for this child and state whether the child is being dosed properly.
The child is being dosed properly.
