The physician orders 5 mg of diazepam IM for anxiety. The vial on hand reads 5 mg/mL. How many milliliters should be administered?

The physician orders 5 mg of diazepam IM for anxiety. The vial on hand reads 5 mg/mL. How many milliliters should be administered?

• A. 0.5 mL
• B. 2 mL
• C. 1 mL
• D. 0.1 mL

Answer: (C)

Understanding how to turn a prescribed dose into a syringe volume relies on the relationship: dose (mg) = concentration (mg/mL) × volume (mL). You need 5 mg, and the vial provides 5 mg per 1 mL, so the volume required is 5 mg ÷ 5 mg/mL = 1 mL. Therefore, administer 1 mL. If you used 0.5 mL, you’d give 2.5 mg; 2 mL would be 10 mg; 0.1 mL would be 0.5 mg. None of those match the intended 5 mg.

Understanding how to turn a prescribed dose into a syringe volume relies on the relationship: dose (mg) = concentration (mg/mL) × volume (mL). You need 5 mg, and the vial provides 5 mg per 1 mL, so the volume required is 5 mg ÷ 5 mg/mL = 1 mL. Therefore, administer 1 mL.

If you used 0.5 mL, you’d give 2.5 mg; 2 mL would be 10 mg; 0.1 mL would be 0.5 mg. None of those match the intended 5 mg.