74. A prescription order is written for 40 mg of a drug. It is available in a 10 mL vial with a concentration of 25 mg/mL. How many mL are needed for the ordered dose?
Answer: B
1.6 mL are needed for the ordered dose.
To administer a dose of 40 mg from a solution with a concentration of 25 mg/mL, 1.6 mL of the solution is required.
A) 0.625
This option is incorrect because 0.625 mL would only provide 15.625 mg of the drug (0.625 mL x 25 mg/mL), which is insufficient to meet the prescribed dose of 40 mg.
B) 1.6
This is the correct answer, as 1.6 mL multiplied by the concentration of 25 mg/mL results in exactly 40 mg of the drug (1.6 mL x 25 mg/mL = 40 mg), fulfilling the prescription order.
C) 6.25
This option is incorrect because 6.25 mL would yield 156.25 mg of the drug (6.25 mL x 25 mg/mL), which exceeds the required dose of 40 mg significantly.
D) 16
This option is also incorrect; 16 mL would provide 400 mg of the drug (16 mL x 25 mg/mL), which is much more than the ordered 40 mg dose, making it an inappropriate choice.
Conclusion
The correct amount needed for the ordered dose is 1.6 mL, as this volume provides the exact 40 mg required. All other options fail to meet the dosage requirement, either falling short or exceeding the necessary amount significantly.