Med Math (Dosage Calculations)
Order: Mezlocillin 3 g IVPB in 130 mL normal saline (NS) over 1 hour. Drop factor is 10 gtt/mL. The nurse will administer how many drops per minute? (round to nearest whole number)
gtt/min = 10gtt/1mL x 130mL/1hr x 1hr/60mins = 1300gtt/60mins = 22 gtt/min
As a nurse receives an order that states "start 1,500 L 0.9% sodium chloride (NaCl) at 75 mL/hr". How many hours will this infusion run for?
hr = 1hr/75mL x 1500mL/1 = 1500hr/150 = 20 hrs
A nurse is caring for a client prescribed sertraline 50 mg PO 2 times daily. Each tablet comes as 10 mg/tab. How many tablets will the client receive per dose?
tabs/dose = 1tab/10mg x 50mg/1dose = 50tabs/10dose = 5 tabs/dose
A patient is to receive 500 mL lactated Ringer solution infused at a rate of 80 mL/hr. If the IV was started at 1900, when will it be completed? (record answer in military time)
500mL/80mL = 6.25 (convert the minutes) 60mins x 0.25mins = 15mins = 6hrs 15mins (Record in military time) 1900 + 6 hrs 15mins = 0115
Order: morphine 8 mg IM STAT Available: morphine 15 mg/mL. How many mL will the nurse administer? (round to the tenths)
mL = 1mL/15mg x 8mg/1 = 8mL/15 = 0.5 mL
A nurse is caring for a client prescribed lorazepam 800 mcg IM daily. Available is lorazepam 2 mg/1mL. Injectable solution, how many mL will the nurse administer? (round to nearest tenths)
mL = 1mL/2mg x 1mg/1000mcg x 800mg/1 = 800mL/2000 = 0.4 mL
4 teaspoons equal to how many milliliters?
mL = 5mL/1tsp x 4tsp/1 = 20mL
The prescriber orders Medication F 150 mcg PO q.12h. The pharmacy sends a bottle labeled: Medication F 0.05 mg/mL. How many milliliters will the nurse administer with each dose?
mL/dose = 1mL/0.05mg x 1mg/1000mcg x 150mcg/1dose = 150mL/50 dose = 3 mL/dose
Order: gentamicin 100 mcg IVq6h Supply: gentamicin 250 mg/mL Available: mL every 6 hrs. How many milliliters will be given per dose? (Round to nearest tenths)
mL/dose = 1mL/250mg x 100mg/1dose = 100mL/250dose = 0.4 mL/dose
A nurse is preparing to administer 0.45% sodium chloride (NaCl) 1000 mL IV to infuse over 8hrs. The nurse should set the IV pump to deliver how many mL/hr? (round to nearest whole number)
mL/hr = 1000mL/8hr = 125 mL/hr
The order is for 1,200 mL D51/2 NS every 8 hours for a client. Calculate the flow rate in milliliters per hour for the ordered medication (record in whole number)
mL/hr = 1200mL/8hrs = 150 mL/hr
The primary healthcare provider orders 1,500 mL IV therapy that runs at 150 mL/hr. What is the completion time of the IV if the nurse starts the IV at 1600? (military time)
mL/hr = 1hr/150mL x 1500mL/1= 1500hr/150 = 10hrs 1600 + 10hrs = 0200
A physician orders levothyroxine (Synthroid), 150 mcg orally daily. The medication label reads Synthroid, 0.1 mg/tablet. The nurse administers how many tablets to the client?
tabs = 1tab/0.1mg x 1mg/1000mcg x 150mcg/1 = 150tabs/100 = 1.5 tabs
A nurse practitioner prescribes Medication C 25 mg PO bid. The pharmacy supplies Medication C as 10 mg scored tablets. How many tablets should the nurse instruct the patient
tabs/dose = 1tab/10mg x 25mg/1dose = 25tab/1dose = 2.5 tabs/dose
