In push-dose epinephrine prepared by mixing 9 mL of normal saline with 1 mL of epinephrine 0.1 mg/mL in a 10 mL syringe, how much epinephrine is delivered per dose?

• A. 0.01 mg
• B. 0.1 mg
• C. 1 mg
• D. 0.001 mg

Answer: (A)

Dilution sets the amount delivered per dose by keeping the total drug amount the same while increasing volume, which lowers concentration. Here, 1 mL of epinephrine at 0.1 mg/mL contains 0.1 mg of drug. When you add 9 mL of normal saline, you have 10 mL total with the same 0.1 mg of epinephrine. The final concentration becomes 0.1 mg / 10 mL = 0.01 mg/mL (10 micrograms per mL). If a dose is 1 mL from this syringe, you deliver 0.01 mg of epinephrine per dose. If a smaller volume is given, the amount scales accordingly (for example, 0.5 mL would deliver 0.005 mg, or 5 micrograms).