Calculations V: Exam - Style Math Practice

Term
1 / 24
A pharmacist receives a prescription for a 1.5% w/w hydrocortisone cream using cold cream as the base. She will use hydrocortisone injection (100 mg/mL, SG 1.5) to prepare the prescription because she has no hydrocortisone powder in stock. How many grams of cold cream are required to compound 60 grams of the preparation? Round to the nearest one decimal place.
Click the card to flip 👆
Terms in this set (24)
A pharmacist receives a prescription for a 1.5% w/w hydrocortisone cream using cold cream as the base. She will use hydrocortisone injection (100 mg/mL, SG 1.5) to prepare the prescription because she has no hydrocortisone powder in stock. How many grams of cold cream are required to compound 60 grams of the preparation? Round to the nearest one decimal place.
- 1.5% = 1.5 g/100 g
- 1.5 g/100 g = x/60 g = 0.9 g total hydrocortisone required
- 100 mg/mL *x = 900 mg = 9 mL
- 9 mL * 1.5 g/mL = 13.5 g
- 60 g -13.5 g = 46.5 g cold cream required
How many milliliters of a 1:2500 w/v solution of aluminum acetate can be made from 100 mL of 0.2% solution?
1/2500 * x/100 = 0.04%
- 0.2100 = 0.04 x
- x = 500
- 500 mL
A pharmacist will prepare an amoxicillin suspension to provide a 1600 mg daily dose for a child with an otitis media infection. The dose will be divided BID. To prepare amoxicillin 200 mg/5mL, the pharmacist should add 76 mL of water to the powder for a final volume of 100 mL. The pharmacist mistakenly adds too much water and finds that the final volume is 110 mL. The pharmacy has no other bottles of amoxicillin, so the pharmacist will dispense the bottle with extra water added. How many mL should the patient take twice daily to receive the correct dose? Round to the nearest whole number.
- 200 mg/5mL *100 mL = 4000 mg total
- 4g/110 mL = x/100 = 3.63% = 3.63 g/100 mL
- Patient requires 800 mg BID
- 3.63 g/100 mL = 36.36 mg/mL
- 36.36 mg/mL * x = 800 mg
- x = 22 mL
- 22 mL BID
What is the ratio strength w/v of 50 mL containing a 1:20 w/v ammonia solution diluted to 1 liter?
- 1:20 = 1/20 = 0.05 g/mL
- 0.05 g/mL * 50mL = 2.5 g
- 2.5 g/1000 mL = 0.0025 g/mL
- 0.0025 g/mL = 1/x = 400
- 1:400
A pharmacist receives an order for sodium chloride 4 mEq/kg/day for a patient who weighs 165 pounds. Using 1/2 NS, how many liters will the patient require per day? Round to the nearest tenth. (MW NA = 23, MW Cl = 35.5)
- 165 pounds = 75 kg
- 4 mEq * 75 = 300 mEq/day
- 1/2 NS = 0.45 g/100 mL = 0.045 g/mL
- mEq = (mg * valence)/MW
- 300 mEq = x*1/58.5 = 17550 mg = 17.550 g
- 0.0045 g/mL * x = 17.550 g = 3900 mL = 3.9 L
- 3.9 L
A patient is receiving D5 1/2NS with potassium chloride at 20 drops/min. After 10 hours, the patient has received a total of 40mEq of potassium chloride using tubing that delivers 15 drops/mL. What is the percentage concentration of potassium chloride in the patient's IV fluid? Round to 2 decimal places. MW of K = 39, MW of Cl = 36
- mEq = (mg * valence)/MW
- 40 = x*1/75 = 3000 mg
- 20 drops/min * 600 minutes (10 hours) = 12000 drops
- 12000 drops * 1/15 drops/mL = 800 mL
- 3g/800mL = x/100mL = 0.375 = 0.38%
An order is written for a dopamine drip in the ICU. The order reads "Start dopamine drip at 3 mcg/kg/min, titrate by 5 mcg/kg/min Q5 minutes to achieve SBP above 100 mmHg. Page the critical care resident for additional orders if maximum dose of 20 mcg/kg/min is reached. The patient weighs 165 pounds and the ICU stocks premixed dopamine drips (400 mg/250 mL) in the automated dispensing cabinet. What rate (mL/hr) should the dopamine drip be started at? round to the nearest whole number.
- 165 pounds = 75 kg
- 3 mcg/kg/min * 75 kg = 225 mcg/min
- 400 mg/250 mL = 1.6 mg/mL = 1600 mcg/mL
- 225 mcg/min*1/1600 mcg/mL = 0.140625 mL/min
- 0.140625 mL/min * 60 min/hr = 8.4375 mL/hr = 8 mL/hr

8 mL/hr
A 46 year old female with radiation enteritis is receiving 1800 kcal from her parenteral nutrition. The solution contains amino acids, dextrose, and electrolytes. There are 84.5 grams of protein in the PN and it is running at 85 mL/hr over 24 hours. What is the final concentration of dextrose in the PN solution? Express the answer as a percentage. Round to the nearest whole number.
- 84.5 G protein * 4 kcal/g = 338 kcal
- 1800 - 338 kcal = 1462 kcal
- 1462 kcal = 3.4 kcal/g = 430 g of dextrose
- 85 mL/hr * 24 = 2040 mL
- 430 g/2040 mL = x/100 mL = 21%

21%
ML is a 165 pound male receiving a premixed dopamine drip 400 mg/250 mL in the ICU. The order states that the drip can be titrated to a maximum dose of 20 mcg/kg/min. What is the maximum rate (mL/hr) at which the drip can be run? Round to the nearest whole number
- 165 pounds = 75 kg
- 20 mcg/kg/min * 75 kg = 1500 mcg = 1.5 mg/min
- 1.5 mg/min *60 min/hr = 90 mg/hr
- 400 mg/250 mL = 1.6 mg/mL
- 90 mg/hr * 1/1.6 mg/mL = 56.25 mL/hr = 56 mL/hr

56 mL/hr
A pharmacist in an oncology clinic receives the following prescription for a patient with Hodgkin's lymphoma: Prednisone 40 mg/m^2/day PO on days 1-14. The patient is 5'1'' and weighs 116 pounds. The hospital uses the following formula for BSA (m^2) = 0.007184 x height (cm)^0.725 *weight (kg)^0.425. How many 20 mg tablets should be dispensed?
- Height = 61 inches = 155 cm
- Weight = 116 pounds = 53 kg
- BSA = 0.007184 155^0.725 52.72^0.425 = 0.00718438.725.39= 1.5m^2
- 40 mg/m^2/day * 2.37 m^2 = 60 mg
- 60 mg/20 mg tablets = 3 tablets/day
- 3 tablets/day * 14 days = 42 tablets total

42 tablets total
A nephrologist is treating a patient with hyponatremia. She estimates the patient's sodium deficit to be 210 mEq. How many milliliters of normal saline (MW NA =23, MW Cl = 35.5) will be required to replace the deficit?- mEq = [mg * valence]/MW - 210 = x*1/58.5 = 12285 mg = 12.285 g - NS = 0.9g/100 mL = 0.009 g/mL - 0.009 g/mL * x = 12.285 g = 1365 mL 1365 mL requiredA pharmacy technician is asked to compound three 500 mL doses of 5% albumin. How many 50 mL vials of 25% albumin will be required?- 5% = 5g/100 mL = 0.05 g/mL - 0.05 g/mL * 500 mL*3 doses = 75g - 25% = 25g/100 mL - 25 g/100 mL = x/50 = 12.5 g - 75g/12.5 g = 6 vialsA patient is to receive a potassium acetate infusion prepared by adding 9 mL of 39.2% potassium acetate to 0.45% NS to make 1 liter. The patient is to receive the potassium acetate at 5 mEq/hr. What rate (mL/hr) qill provide this dose? Round to the nearest whole number. (MW of K = 39 MW of acetate = 59 )- 39.2 g/100 mL = x/9 mL = 3.528 g = 3528 mg - x mEq = 3528 mg * 1/98 = 36 mEq - 1000 mL/36 mEq * 5 mEq/hr = 138.88 mL/hr = 139 mL/hrAn intravenous infusion contains 2 mL of a 1:1000 w/v solution of epinephrine and 250 mL of D5W. At what flow rate (mL/min) should the infusion be administered to provide 0.3 mcg/kg/min of epinephrine to an 80 kg patient? Round to the nearest whole number.- 0.3 mcg/kg/min * 80 kg = 24 mcg/min - 1:1000 = 0.1% = 0.001 g/mL - 1000 mcg/mL * 2 mL = 2000 mcg - 252 mL/2000 mcg * 24 mcg/min = 3 mL/minA cough syrup contains 4 grams of brompheniramine maleate per liter. How many milligrams are contained in one teaspoonful of the elixir?- 4 g/L = 4000 mg/1000 mL = 4 mg/mL - 1 tsp = 5 mL - 4 mg/mL * 5 mL = 20 mgA patient is to receive acyclovir 5 mg/kg every 8 hours for an acute outbreak of herpes zoster. What daily dose in milligrams should a 110 pound female receive?- 110 pounds = 50 kg - 5 mg/kg = 250 mg - 250 mg * 3 times per day = 750 mg totalA patient received 4 mg IV morphine. What is an equivalent dose of oral hydromorphone? Round to the nearest whole number (10 mg of IV morphine is equivalent to 7.5 mg of oral hydromorphone).- 10 mg/7.5 mg = 4 mg/x = 3 mg oral hydromorphoneIf 200 capsules contain 500 mg of an active ingredient, how many milligrams of the active ingredient will 76 capsules contain?- 200 capsules/500 mg = 76/x = 190 mg 190 mgIf phenobarbital elixir contains 18.2 mg of phenobarbital per 5 mL, how many grams of phenobarbital would be used in preparing a pint of the elixir? Round to the nearest tenth.- 18.2 mg/5 mL = 3.64 mg/mL = 0.00364 g/mL - 1 pint = 16 fl oz = 480 mL - 0.00364 g/mL * 480 = 1.74 g = 1.7 gA penicillin V 250 mg tablet equals 400,000 units of penicillin activity. A patient is taking penicillin V 500 mg tablets QID for 7 days. How much penicillin activity, in units, will this patient receive in the total prescription?- 400,000 units/250 mg = x/500 mg = 800,000 units - 800,000 * 4 * 7 = 22,400,000 unitsOral potassium chloride 20% solution contains 40 mEq of potassium per 15 mL of solution. A patient needs 25 mEq of potassium daily. How many milliliters of 20% potassium chloride should the patient take? Round to the nearest tenth.40 mEq/15 mL = 25 mEq/x = 7.49 mL = 9.36 mL = 9.4 mLPatient JR is 41 years old and weighs 70 kg and is 6'1''. The patient is to receive IV Bactrim 20 mg/kg/day Q6h. What dose of IV bactrim should be given according to the following parameters? CrCl More than 30 mL/min = no dose adjustment 15-30 mL/min = administer 50% of dose Less than 15 mL = Do not give dose- TBW = 70 kg - IBW = 50 + 2.3 * 13 = 79.9 kg - (140-41) * 70/(72 * 0.8) = 120 Keep dose the same = 1400 mg/day = 350 mg Q6hMH is a 72 year old male patient hospitalized with decompensated HF and fever. Cultures are positive for aspergillosis. MH weighs 110 kg and will receive 0.25 mg/kg per day of amphotericin B (diluted to 0.1 mg/mL) by IV ifusion. How many milliliters of amphotericin solution are required to deliver the daily dose?- 110 kg * 0.25 mg/kg = 27.5 mg/day - 0.1 mg/mL * x = 27.5 mg = 275 mLWhat is the pH of a solution containing 2 mole of a weekly basic drug and 0.02 mole of its salt per liter of solution? pKa = 9.36- pH = 9.36 + log (0.2/0.02) = 9.36 + 1 = 10.36