Dosage Calculations Study Guide

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Sample questions from Dosage Calculations Study Guide

This material has 10 questions with answers and rationales. Here are the first 5.

1. 1.A client is prescribed 0.75 g of an oral medication. The available tablets contain 250 mg each. How many tablets should the nurse administer?

   • A.0.3 tablet
   • B.3 tablets
   • C.1 tablet
   • D.30 tablets

   Rationale: C is correct: 0.75 g = 750 mg, and 750/250 = 3 tablets. A reflects a decimal or conversion error. B provides only 250 mg, one third of the prescribed dose. D provides 7,500 mg, ten times the prescribed dose.

2. 2.An order specifies 180 mg of an oral suspension. The label reads 120 mg/5 mL. What volume should the nurse measure?

   • A.7.5 mL
   • B.15 mL
   • C.5 mL
   • D.1.5 mL

   Rationale: B is correct: 180 mg x 5 mL/120 mg = 7.5 mL. A calculates the dose ratio but omits the labeled 5 mL quantity. C supplies only 120 mg. D supplies 360 mg, twice the prescribed dose.

3. 3.A child weighs 44 lb. A fictional medication is prescribed at 30 mg/kg/day divided into three equal doses. Use 2.2 lb = 1 kg. How many milligrams should the child receive per dose?

   • A.1,320 mg
   • B.600 mg
   • C.440 mg
   • D.200 mg

   Rationale: A is correct: 44/2.2 = 20 kg; 20 x 30 = 600 mg/day; 600/3 = 200 mg/dose. B is the daily total, not one dose. C results from using 44 as kilograms and then dividing by three. D uses pounds as kilograms and also fails to divide the daily total.

4. 4.A 16 kg child is prescribed a fictional medication at 250 mg every six hours. The supplied safe range is 40-60 mg/kg/day in four divided doses. What is the nurse's best action?

   • A.Reduce each dose to 240 mg without contacting the prescriber.
   • B.Administer because 250 mg is below 960 mg.
   • C.Hold the dose and clarify the order because the daily amount exceeds the supplied range.
   • D.Administer because the ordered daily amount is within range.

   Answer and rationale are in the full material.

5. 5.A vial contains 1 g of medication. The instructions state that adding 3.6 mL of diluent produces a final concentration of 250 mg/mL. The order is for 625 mg. What volume should the nurse withdraw?

   • A.3.6 mL
   • B.2.5 mL
   • C.4 mL
   • D.2.25 mL

   Answer and rationale are in the full material.