78. A patient needs 1.5 million units of penicillin G benzathine in a single IM injection. Supplied in 2 mL vials containing 1.2 million units per vial. Volume to draw?
Answer: D
The volume to draw is 2.5 mL.
To administer 1.5 million units of penicillin G benzathine, the patient will require 2.5 mL, as each vial contains 1.2 million units in 2 mL. Thus, two vials must be utilized to meet the required dosage.
A) 0.6
This option is incorrect because drawing only 0.6 mL would only provide approximately 360,000 units of penicillin G benzathine, which is significantly less than the required 1.5 million units.
B) 0.8
This choice is also incorrect as drawing 0.8 mL would yield about 480,000 units of penicillin G benzathine. This amount is still far below the necessary dosage for the patient.
C) 1.3
Option C is not correct since 1.3 mL would provide around 780,000 units of penicillin G benzathine. This quantity is insufficient for the patient's requirement of 1.5 million units.
D) 2.5
This option is correct. To achieve the required 1.5 million units, two vials must be utilized, which totals 2.5 mL since each vial contains 1.2 million units in 2 mL.
Conclusion
The correct volume to draw is 2.5 mL, as it allows for the administration of the required 1.5 million units of penicillin G benzathine. All other options fail to meet the necessary dosage, highlighting the importance of accurate medication calculations in clinical settings.