COMPLEX / DORIS TURNER MED MATH QUESTIONS

1. Problem type: IV infusion rate + infusion pump Medication: azithromycin PROBLEM Suppose Mrs. Turner’s orders call for 500 mg of azithromycin to be administered intravenously for community­acquired pneumonia. The solution has been diluted to a concentration of 2 mg/mL and needs to be administered over 1 hour. At what rate should the infusion pump be set? HINT Start by figuring out how many milliliters will be needed to administer the ordered dose. SAMPLE SOLUTION 1. Determine how many milliliters of the concentration will be delivered to administer the ordered dose. 500 mg x 1 mL = 250 mL 2 mg 2. Divide the total number of mL needed to deliver the 500 mg by the expected duration of 1 hour. 250 mL = 250 mL/hr 1 hr ANSWER Number: 250 Units / Rate: mL/hr 2. Problem type: Dosage calculation + Stock on hand Medication: venlafaxine PROBLEM Mrs. Turner’s daily medications include venlafaxine extended­release, 150 mg, by mouth, once a day. However, the hospital pharmacy only carries 75 mg extended­release tablets. How many tablets of venlafaxine extended­release should be administered to her? HINT You can use the equation below, where X is the number of tablets that should be administered. D (ordered dose) x Quantity = X H (dose on hand) SAMPLE SOLUTION 1. Determine what information you have. D (ordered dose) = 150 mg H (dose on hand) = 75 mg Q (quantity) = 1 tablet 2. Plug into the equation and solve. D (150 mg) x 1 tablet = X H (75 mg) X = 2 tablets ANSWER Number: 2 Units: tablets 3. Problem type: Total daily dosage Medication: Acetaminophen @ hospital ­ hypothetical Suppose Mrs. Turner’s provider updated her order for 325 mg, 2 tabs, by mouth q6h PRN temp. > 100.5 F to 325 mg, 2 tabs, by mouth q4h PRN temp. > 100.5 F. The Davis’s Drug Guide reports that acetaminophen has a maximum recommended dosage of 4 g/day. How many doses can Mrs. Turner take without exceeding the recommended maximum dosage? HINT There are 1000 mg in one gram. SAMPLE SOLUTION 1. Determine how many milligrams are in 4 grams. 4 g x 1000 mg = 4000 mg 1 g 2. Determine how many 325 mg tablets go into 4000 mg. 4000 mg x 1 tablet = 12.3 tablets 325 mg 3. Round down to the nearest whole tablet = 12 tablets 4. Divide the total number of tablets by the number tablets in a dose. 12 tablets total x 1 dose = 6 doses 2 tablets ANSWER Number: 6 Units: doses 4. Problem type: Total daily dose calculation Medication: acetaminophen @ hospital PROBLEM Suppose Mrs. Turner’s current temperature is 100.8 F. For temperatures greater than 100.5 F, the prescriber’s order allows acetaminophen, 325 mg, 2 tabs, by mouth, every 6 hours. Assume that on her first day of hospitalization, Mrs. Turner’s temperature is greater than 100.5 F three times. How many grams of acetaminophen will she have ingested on her first day of hospitalization? Round your answer to hundredths. HINT Multiply the number of taken doses by the number of tablets. SAMPLE SOLUTION 1. Multiply the number of doses taken by the number of tablets per dose. 3 doses x 2 tablets = 6 tablets 1 dose 2. Multiply the dosage of acetaminophen by the number of tablets. 6 tablets x 325 mg = 1950 mg 1 tablet 3. Convert the total daily milligrams to grams. 1950 mg x 1 g = 1.95 g 1000 mg ANSWER Number: 1.95 Units: g