A patient must receive 50 units of Humulin regular insulin. The label reads 100 units = 1 ml. How many milliliters should the nurse administer?
A. 0.5 ml
B. 0.75 ml
C. 1 ml
D. 2 ml
Correct Answer: A. 0.5 ml
There are 3 primary methods for calculation of medication dosages; Dimensional Analysis, Ratio Proportion, and Formula or Desired Over Have Method. Desired Over Have or Formula Method uses a formula or equation to solve for an unknown quantity (x) much like ratio proportion.
Option B: Drug calculations require the use of conversion factors, for example, when converting from pounds to kilograms or liters to milliliters. Simplistic in design, this method allows clinicians to work with various units of measurement, converting factors to find the answer. These methods are useful in checking the accuracy of the other methods of calculation, thus acting as a double or triple check.
Option C: The Ratio and Proportion Method has been around for years and is one of the oldest methods utilized in drug calculations (as cited in Boyer, 2002)[Lindow, 2004]. Addition principals is a problem-solving technique that has no bearing on this relationship, only multiplication, and division are used to navigate through a ratio and proportion problem, not adding.
Option D: High-risk medications such as heparin and insulin often require a second check on dosage amounts by more than one provider before the administration of the drug. Follow institutional policies and recommendations on the double-checking of dose calculations by another licensed provider.